JP5327490B2 - COMMUNICATION SYSTEM, RADIO BASE STATION DEVICE, RADIO TERMINAL DEVICE, COMMUNICATION CONTROL METHOD, AND COMMUNICATION CONTROL PROGRAM - Google Patents

Description

  The present invention relates to a communication system, a radio base station apparatus, a radio terminal apparatus, a communication control method, and a communication control program, and in particular, an operation in which the radio terminal apparatus intermittently stops monitoring communication control information from the radio base station apparatus. The present invention relates to a communication system, a radio base station apparatus, a radio terminal apparatus, a communication control method, and a communication control program in a communication system that can be performed.

  Conventionally, in a mobile communication system, a communication service is provided by a radio base station apparatus (hereinafter also referred to as a macro base station) that forms an area in which a cell having a radius of several hundred meters to several tens of kilometers, that is, a radio terminal apparatus can communicate. It was.

  In recent years, due to a dramatic increase in the number of subscribers of mobile communication services and an increase in the amount of communication traffic due to data communication, subscribers and communication traffic are distributed by forming smaller radius cells, and a certain level of communication It is desirable to provide speed to users in a stable manner. In addition, in order to deal with dead zones associated with the increase in the number of buildings, it is desired to install radio base station devices on the corporate floor and in ordinary households.

  Together with these demands, the processing capability of various devices used in the radio base station apparatus has been dramatically improved, and the miniaturization of the radio base station apparatus has progressed. Collecting.

  The femto cell formed by the femto base station, which is a kind of small base station, has a small radius of around 10 meters, so the femto base station is outside the range of the macro cell formed by the macro base station. It may be used in places such as indoors and underground malls where it is difficult to install base stations.

  In addition, since many femto base stations are installed in a specific area, it is difficult to connect the femto base stations directly to the core network. For this reason, it is conceivable that a large number of femto base stations installed in a specific area are once connected to a gateway device such as a HeNB-GW, and the femto base station and the core network are connected via the HeNB-GW.

  In addition to the femto base station, a pico base station that forms a pico cell having a radius of, for example, 100 meters to 200 meters is also developed as a kind of small base station based on a macro base station.

  Here, the DRX (Discontinuous Reception) operation in which the wireless terminal device intermittently stops monitoring the PDCCH (Physical Downlink Control Channel) including the communication control information from the wireless base station device is a 3GPP TS 36.321 V10.4.0 2011.12 (non- Patent Document 1) discloses this. By performing the DRX operation, the wireless terminal device does not need to continuously monitor the PDCCH, so that power consumption can be reduced.

3GPP TS 36.321 V10.4.0 2011.12

  For example, the radio base station apparatus determines the execution of the handover operation of the radio terminal apparatus based on a measurement result notification (Measurement Report) indicating the reception power of the radio signal from the radio base station apparatus in the radio terminal apparatus.

  Here, when the DRX operation is performed, the radio terminal apparatus cannot transmit the measurement result notification to the radio base station apparatus except during the ON period in which the PDCCH is monitored. For this reason, the timing of the handover operation is too late “Too Late HO”, that is, before the handover starts or during the handover process, a radio link failure (RLF) occurs in the handover source radio base station apparatus. May occur.

  Therefore, in the technique described in Non-Patent Document 1, in order to suppress the occurrence of “Too Late HO”, in addition to the long DRX using the normal DRX cycle, a short DRX having a shorter period than the long DRX is provided. .

  On the other hand, in a heterogeneous network that is a communication system in which femto base stations, pico base stations, and macro base stations are mixed as described above, for example, a plurality of femto cells or pico cells are formed in a macro cell. For this reason, handover of the wireless terminal device is likely to occur, and the situation of performing handover is complicated. That is, in a heterogeneous network, the optimal handover timing differs depending on the combination of various base stations, and therefore it is difficult to set an optimal DRX cycle fixedly. When an inappropriate DRX cycle is set, various problems such as an increased frequency of failed handover operations and an increase in power consumption of the wireless terminal device occur.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to enable communication in which a wireless terminal device can intermittently stop monitoring communication control information from a wireless base station device. In the system, a communication system, a radio base station apparatus, a radio terminal apparatus, a communication control method, and a communication capable of achieving a stable balance of communication and suppressing power consumption of the radio terminal apparatus by appropriately performing the operation It is to provide a control program.

  (1) In order to solve the above-described problem, a communication system according to an aspect of the present invention is a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus, The wireless terminal device communicates with the wireless base station device based on the communication control information received from the wireless base station device, and does not have to monitor the ON period during which the communication control information should be monitored and the communication control information. It is possible to perform an intermittent monitoring operation that periodically repeats a good off-period, and the cycle that can be set as the cycle of the intermittent monitoring operation is different from the first cycle and shorter than the first cycle. There are a plurality of second periods that can be set so that the wireless base station apparatus is in a state where the wireless terminal apparatus performs the intermittent monitoring operation in the first period, As the period of the serial intermittent monitoring operation, the settings corresponding to the second cycle selected from the plurality of second periodic requests to said wireless terminal.

  With such a configuration, it is possible to perform an intermittent monitoring operation by selecting an appropriate period and to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner. In addition, since the radio base station apparatus is configured to select the period of the intermittent monitor operation, it is not necessary to acquire information used for selection determination of the period of the intermittent monitor operation in the radio terminal apparatus. It is no longer necessary to transmit the information.

  (2) Preferably, the radio base station apparatus is configured in a state where a predetermined condition regarding a communication state of the radio terminal apparatus is satisfied in a state where the radio terminal apparatus performs the intermittent monitoring operation in the first period. Corresponding to the second period selected from the plurality of second periods based on information on other radio base station apparatuses other than the self reported as being present from the radio terminal apparatus as the period of the intermittent monitoring operation The wireless terminal device is requested to set to be performed.

  In this way, with the configuration in which the cycle of the intermittent monitoring operation is selected based on the information about the neighboring base station that is a wireless base station device other than itself, for example, even when the optimum handover timing is different in each base station, An intermittent monitoring operation can be performed. In addition, the configuration in which the period of the intermittent monitoring operation is selected in the radio base station apparatus eliminates the need for the radio terminal apparatus to acquire information on neighboring base stations. No need to send.

  (3) More preferably, the radio base station apparatus is selected from the plurality of second periods based on a type of a radio base station apparatus other than the self reported to be present from the radio terminal apparatus A setting corresponding to the second period is requested to the wireless terminal device.

  With such a configuration, it is possible to select the period of the intermittent monitoring operation based on an appropriate reference based on the type of the surrounding base station.

  (4) More preferably, the radio base station device has selected from the plurality of second periods based on an operation setting of another radio base station device other than the radio base station device whose presence is reported from the radio terminal device A setting corresponding to the second period is requested to the wireless terminal device.

  With such a configuration, the cycle of the intermittent monitoring operation can be selected based on an appropriate reference based on the operation settings of the neighboring base stations.

  (5) More preferably, the radio base station apparatus has selected from the plurality of second periods based on installation conditions of other radio base station apparatuses other than the radio base station apparatus whose presence is reported from the radio terminal apparatus A setting corresponding to the second period is requested to the wireless terminal device.

  With such a configuration, it is possible to select the period of the intermittent monitoring operation based on an appropriate reference based on the installation status of the surrounding base stations.

  (6) More preferably, the radio base station device uses the radio terminal device to report the presence of another radio base station device other than itself as the predetermined condition.

  With such a configuration, for example, when the possibility that the handover operation of the wireless terminal apparatus is performed becomes high to some extent, switching from the first period to the second period can be appropriately performed.

  (7) More preferably, the communication system includes a small base station and a macro base station as the radio base station apparatus, and the radio base station apparatus is the other of which the existence is reported from the radio terminal apparatus. When a small base station is included in the wireless base station apparatus, the wireless terminal apparatus is requested to set the second period shorter than in the case where the small base station is not included.

  With such a configuration, when the neighboring base station is a small base station such as a femto base station or a pico base station, a shorter appropriate cycle can be selected as the cycle of the intermittent monitoring operation.

  (8) More preferably, the radio base station apparatus performs the predetermined process when the transmission power of the radio signal of the other radio base station apparatus reported to be present from the radio terminal apparatus is less than a predetermined threshold. The wireless terminal device is requested to set the second period, which is shorter than the case where it is equal to or greater than the threshold value.

  With such a configuration, when the transmission power of the neighboring base station is small, a shorter appropriate cycle can be selected as the cycle of the DRX operation.

  (9) More preferably, when the distance between base stations of the other radio base station apparatus reported to be present from the radio terminal apparatus is less than a predetermined threshold, the radio base station apparatus The wireless terminal device is requested to set the second period which is shorter than the case where the value is equal to or greater than the threshold.

  With such a configuration, a shorter appropriate cycle can be selected as the cycle of the intermittent monitoring operation when the distance between the base stations between the neighboring base station and the other radio base station device is small.

  (10) Preferably, the radio base station apparatus transmits the communication control information to the radio terminal apparatus so that the radio base station apparatus arrives at the radio terminal apparatus during the ON period in the selected second period.

  With such a configuration, even if the cycle of the intermittent monitoring operation is changed, the wireless terminal device that is performing the intermittent monitoring operation can reliably receive the communication control information, and communication with the wireless terminal device can be satisfactorily continued. .

  (11) Preferably, the wireless terminal apparatus restarts the intermittent monitoring operation in the first period when a predetermined time has elapsed after starting the intermittent monitoring operation in the second period, and the wireless base station apparatus Transmits the communication control information to the wireless terminal so as to arrive at the wireless terminal device during the on-period in the first period when the predetermined time has elapsed since the start of the intermittent monitoring operation in the second period. Send to device.

  With such a configuration, even when the wireless terminal device autonomously switches from the second cycle to the first cycle, the wireless terminal device that is intermittently monitoring operates to reliably receive communication control information, and the wireless terminal device Communication with can be continued well.

  (12) Preferably, the wireless base station device communicates with itself or in the wireless terminal device as a cycle of the intermittent monitoring operation in a state where the wireless terminal device performs the intermittent monitoring operation in the first cycle. A setting corresponding to the second period selected from the plurality of second periods based on traffic is requested to the wireless terminal device.

  As described above, with the configuration in which the cycle of the intermittent monitoring operation is selected based on the communication data traffic in the radio base station device or the radio terminal device, the cycle of the intermittent monitoring operation can be appropriately set according to various traffics. it can. Therefore, stable communication and suppression of power consumption of the wireless terminal device can be achieved with a good balance.

  (13) More preferably, the wireless terminal device reports communication traffic from itself to the wireless base station device to the wireless base station device, and the wireless base station device reports the wireless terminal device reported from the wireless terminal device. A setting corresponding to the second period selected from the plurality of second periods based on communication traffic is requested to the wireless terminal device.

  With such a configuration, it is possible to acquire uplink communication traffic in the wireless terminal device and appropriately set the period of the intermittent monitoring operation according to the uplink communication traffic in the wireless terminal device.

  (14) In order to solve the above-described problem, a radio base station apparatus according to an aspect of the present invention is a radio base station apparatus capable of communicating with a radio terminal apparatus, and the radio terminal apparatus includes the radio base station apparatus Intermittent monitor that communicates with the radio base station apparatus based on communication control information received from the terminal and periodically repeats an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored The period that can be set as the period of the intermittent monitoring operation is different from the first period, and a plurality of second periods that can be set to be shorter than the first period. A communication control unit for transmitting the communication control information to the wireless terminal device, and the wireless terminal device performing the intermittent monitoring operation in the first cycle. As the period of the intermittent monitoring operation, and a monitor period setting unit for setting corresponding to the second cycle selected from the plurality of second periodic requests to said wireless terminal.

  With such a configuration, it is possible to perform an intermittent monitoring operation by selecting an appropriate period and to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner. In addition, since the radio base station apparatus is configured to select the period of the intermittent monitor operation, it is not necessary to acquire information used for selection determination of the period of the intermittent monitor operation in the radio terminal apparatus. It is no longer necessary to transmit the information.

  (15) In order to solve the above problem, a radio terminal apparatus according to an aspect of the present invention is a radio terminal apparatus capable of communicating with a radio base station apparatus, and monitors communication control information from the radio base station apparatus. A monitor control unit capable of performing an intermittent monitoring operation that periodically repeats an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored, and the monitor control unit. A communication control unit for communicating with the radio base station apparatus based on the monitored communication control information, and the period that can be set as the period of the intermittent monitoring operation is the same as the first period. There are a plurality of second periods that are different and can be set to be shorter than the first period, and the monitor control unit performs the first period according to a request from the radio base station apparatus. Others perform the intermittent monitoring operation in the second period, sets the one of the plurality of second periods in response to a request from the radio base station apparatus.

  With such a configuration, it is possible to perform an intermittent monitoring operation by selecting an appropriate period and to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner. In addition, since the radio base station apparatus is configured to select the period of the intermittent monitor operation, it is not necessary to acquire information used for selection determination of the period of the intermittent monitor operation in the radio terminal apparatus. It is no longer necessary to transmit the information.

  (16) A radio terminal apparatus according to another aspect of the present invention is a radio terminal apparatus capable of communicating with a radio base station apparatus, and monitors communication control information from the radio base station apparatus, and the communication control information A monitor control unit capable of performing an intermittent monitoring operation that periodically repeats an on period in which to monitor and an off period in which the communication control information need not be monitored, and the communication control monitored by the monitor control unit A communication control unit for communicating with the radio base station apparatus based on the information, and a radio base station apparatus other than the serving base station that is the radio base station apparatus selected by the radio terminal apparatus as a communication partner A base station detection unit for detecting a neighboring base station, and the period that the monitor control unit can set as the period of the intermittent monitoring operation is The first period that is set when the predetermined condition related to the communication state is not satisfied and the first period that is set when the predetermined condition is satisfied can be set to be different from each other and shorter than the first period. A plurality of second periods, and the plurality of second periods is a macro base station period that is set when the base station detector does not detect the presence of a small base station as the peripheral base station. And a small base station cycle that is set when the presence is detected and is shorter than the macro base station cycle.

  As described above, for example, when the optimum handover timing is different in each base station by a configuration in which a period having a different length can be set based on whether or not the neighboring base station is a small base station as the period of the intermittent monitoring operation. However, the intermittent monitoring operation can be performed at an appropriate period, so that the communication can be stabilized and the power consumption of the wireless terminal device can be well balanced.

  (17) A radio terminal apparatus according to another aspect of the present invention is a radio terminal apparatus capable of communicating with a radio base station apparatus, and monitors communication control information from the radio base station apparatus, and the communication control information A monitor control unit capable of performing an intermittent monitoring operation that periodically repeats an on period in which to monitor and an off period in which the communication control information need not be monitored, and the communication control monitored by the monitor control unit A communication control unit for communicating with the radio base station apparatus based on the information, and a radio base station apparatus other than the serving base station that is the radio base station apparatus selected by the radio terminal apparatus as a communication partner A base station detection unit for detecting a neighboring base station, and the period that the monitor control unit can set as the period of the intermittent monitoring operation is The first period that is set when the predetermined condition related to the communication state is not satisfied and the first period that is set when the predetermined condition is satisfied can be set to be different from each other and shorter than the first period. A plurality of second cycles, and the plurality of second cycles is a high power cycle set when the transmission power of the neighboring base station detected by the base station detection unit is equal to or greater than a predetermined threshold. And a low-power cycle that is set when it is less than the predetermined threshold and is shorter than the high-power cycle.

  Thus, the intermittent monitoring operation period can be set to a period with different lengths based on the transmission power of neighboring base stations. Intermittent monitoring operations can be performed at periodic intervals to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner.

  (18) A radio terminal apparatus according to another aspect of the present invention is a radio terminal apparatus capable of communicating with a radio base station apparatus, and monitors communication control information from the radio base station apparatus, and the communication control information A monitor control unit capable of performing an intermittent monitoring operation that periodically repeats an on period in which to monitor and an off period in which the communication control information need not be monitored, and the communication control monitored by the monitor control unit A communication control unit for communicating with the radio base station apparatus based on the information, and a radio base station apparatus other than the serving base station that is the radio base station apparatus selected by the radio terminal apparatus as a communication partner A base station detection unit for detecting a neighboring base station, and the period that the monitor control unit can set as the period of the intermittent monitoring operation is The first period that is set when the predetermined condition related to the communication state is not satisfied and the first period that is set when the predetermined condition is satisfied can be set to be different from each other and shorter than the first period. A plurality of second periods, and the plurality of second periods are for long distances set when the distance between base stations of the neighboring base stations detected by the base station detection unit is equal to or greater than a predetermined threshold. A cycle and a short-distance cycle that is set when it is less than the predetermined threshold and is shorter than the long-distance cycle.

  As described above, for example, an optimal handover timing can be set for each base station with a configuration in which a period of different lengths can be set as a reference period based on the distance between base stations between a neighboring base station and another base station as the period of the intermittent monitoring operation. Even in the case where the stations are different, intermittent monitoring operation can be performed at an appropriate cycle to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner.

  (19) A radio terminal apparatus according to another aspect of the present invention is a radio terminal apparatus capable of communicating with a radio base station apparatus, and monitors communication control information from the radio base station apparatus, and the communication control information A monitor control unit capable of performing an intermittent monitoring operation that periodically repeats an on period in which to monitor and an off period in which the communication control information need not be monitored, and the communication control monitored by the monitor control unit A communication control unit for communicating with the radio base station apparatus based on the information, and the period that the monitor control unit can set as the period of the intermittent monitoring operation is different from the first period in length. And a plurality of second periods that can be set to be shorter than the first period, and the plurality of second periods are communication in the radio base station apparatus or the radio terminal apparatus. And low traffic for the period that is set when traffic is low, is set when the communication traffic is large, and includes the above-described low traffic for periods shorter than high-traffic for the period.

  As described above, the intermittent monitoring operation cycle can be appropriately set according to various traffics by using a configuration in which a cycle having a different length with respect to the communication traffic can be set as the cycle of the intermittent monitoring operation. Therefore, stable communication and suppression of power consumption of the wireless terminal device can be achieved with a good balance.

  (20) A radio terminal apparatus according to another aspect of the present invention is a radio terminal apparatus capable of communicating with a radio base station apparatus, and monitors communication control information from the radio base station apparatus, and the communication control information A monitor control unit capable of performing an intermittent monitoring operation that periodically repeats an on period in which to monitor and an off period in which the communication control information need not be monitored, and the communication control monitored by the monitor control unit A communication control unit for communicating with the radio base station apparatus based on the information, and a radio base station apparatus other than the serving base station that is the radio base station apparatus selected by the radio terminal apparatus as a communication partner And a base station detector for detecting a neighboring base station, and the period that can be set as the period of the intermittent monitoring operation is different from the first period in length, and There are a plurality of second periods that can be set to be shorter than the first period, and the monitor control unit performs the intermittent monitoring operation in the first period from the serving base station. Upon receiving a setting request for two cycles, the intermittent monitoring operation is performed in the second cycle, and the length of the second cycle is selected based on information on the neighboring base stations detected by the base station detector.

  As described above, the intermittent monitoring operation cycle is selected based on the information on the neighboring base stations, so that even if the optimum handover timing is different in each base station, the intermittent monitoring operation is performed at an appropriate cycle to stabilize communication. And power consumption of the wireless terminal device can be well balanced. Further, the configuration in which the length of the second cycle is selected in the wireless terminal device eliminates the need for the wireless base station device to create a different command and transmit it to the wireless terminal device in the request for intermittent monitoring operation in the second cycle.

  (21) A radio terminal apparatus according to another aspect of the present invention is a radio terminal apparatus capable of communicating with a radio base station apparatus, and monitors communication control information from the radio base station apparatus, and the communication control information A monitor control unit capable of performing an intermittent monitoring operation that periodically repeats an on period in which to monitor and an off period in which the communication control information need not be monitored, and the communication control monitored by the monitor control unit A communication control unit for communicating with the radio base station apparatus based on the information, and a radio base station apparatus other than the serving base station that is the radio base station apparatus selected by the radio terminal apparatus as a communication partner And a base station detector for detecting a neighboring base station, and the period that can be set as the period of the intermittent monitoring operation is different from the first period in length, and There are a second period and a third period that can be set to be shorter than the first period, and the monitor control unit performs the intermittent monitoring operation in the first period from the serving base station. When receiving the setting request for the second period, the intermittent monitoring operation is performed in the second period or the third period selected based on the information on the neighboring base station detected by the base station detection unit.

  As described above, the intermittent monitoring operation cycle is selected based on the information on the neighboring base stations, so that even if the optimum handover timing is different in each base station, the intermittent monitoring operation is performed at an appropriate cycle to stabilize communication. And power consumption of the wireless terminal device can be well balanced. Further, the configuration in which the second period or the third period is selected in the wireless terminal apparatus eliminates the need for the wireless base station apparatus to create a different command and transmit it to the wireless terminal apparatus in the request for the intermittent monitoring operation in the second period.

  (22) A radio base station apparatus according to another aspect of the present invention is a radio base station apparatus capable of communicating with a radio terminal apparatus, wherein the radio terminal apparatus receives communication control information from the radio base station apparatus. Can perform intermittent monitoring operation that periodically communicates with the radio base station apparatus based on the ON period during which the communication control information should be monitored and the OFF period during which the communication control information need not be monitored The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period. A terminal communication state determination unit for determining whether or not a predetermined condition relating to a communication state of the wireless terminal device is satisfied, and the wireless terminal device performs the intermittent monitoring operation in the first period. In the state, when the predetermined condition is satisfied for the wireless terminal device, a monitoring cycle setting unit for requesting the wireless terminal device to set the second cycle as a cycle of the intermittent monitoring operation, Based on the information about the neighboring base station, which is another wireless base station device other than itself, reported from the wireless terminal device, the length of the second period when the wireless terminal device performs the intermittent monitoring operation is estimated. A communication control unit for transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device during the on period in the second period of the estimated length.

  As described above, the intermittent monitoring operation cycle is selected based on the information on the neighboring base stations, so that even if the optimum handover timing is different in each base station, the intermittent monitoring operation is performed at an appropriate cycle to stabilize communication. And power consumption of the wireless terminal device can be well balanced. Further, the configuration in which the length of the second cycle is selected in the wireless terminal device eliminates the need for the wireless base station device to create a different command and transmit it to the wireless terminal device in the request for intermittent monitoring operation in the second cycle. Further, even if the cycle of the intermittent monitoring operation is changed in the wireless terminal device, the wireless terminal device that is performing the intermittent monitoring operation can reliably receive the communication control information, and the communication with the wireless terminal device can be continued satisfactorily. .

  (23) Preferably, the wireless terminal device restarts the intermittent monitoring operation in the first cycle when a predetermined time has elapsed after starting the intermittent monitoring operation in the second cycle, and the communication control unit When the predetermined time elapses after the intermittent monitoring operation in the second period starts, the communication control information is transmitted to the wireless terminal apparatus in the on-period in the first period. Send to.

  With such a configuration, even when the wireless terminal device autonomously switches from the second cycle to the first cycle, the wireless terminal device that is intermittently monitoring operates to reliably receive communication control information, and the wireless terminal device Communication with can be continued well.

  (24) A radio base station apparatus according to another aspect of the present invention is a radio base station apparatus capable of communicating with a radio terminal apparatus and operating according to a communication protocol having a plurality of layers, wherein the radio terminal apparatus includes: Based on communication control information received from the radio base station apparatus, the communication is performed with the radio base station apparatus, and an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored The intermittent monitoring operation can be performed repeatedly, and the period that can be set as the period of the intermittent monitoring operation can be set to be different from the first period and shorter than the first period. A plurality of second periods and a third period that can be set to be shorter than the second period, and according to the first layer of the plurality of layers, the wireless terminal A first setting unit capable of switching the first period, the second period, and the third period as the requested period, And a second setting unit capable of selecting the length of the second period according to a second layer higher than the first layer.

  In this way, by effectively utilizing lower layer information, it is possible to perform a quick and appropriate switching process of intermittent monitoring operation that follows changes in the communication environment of the wireless terminal device and the wireless base station device. Therefore, the intermittent monitoring operation can be performed at an appropriate period, and communication can be stabilized and the power consumption of the wireless terminal device can be well balanced.

  (25) Preferably, the first layer is a MAC (Media Access Control) layer defined by 3GPP (Third Generation Partnership Project), and the second layer is an RRC (Radio Resource) defined by 3GPP. Control) layer.

  With such a configuration, in a radio base station apparatus that operates in accordance with a communication protocol defined by 3GPP, intermittent monitoring operation is performed at an appropriate period to stabilize communication and reduce power consumption of the radio terminal apparatus in a well-balanced manner. Can do.

  (26) Preferably, each of the plurality of radio base station devices includes a small base station and a macro base station, and the first setting unit is a radio other than itself that is reported from the radio terminal device. When a small base station is included in the base station device, the wireless terminal device is requested to set the third period.

  With such a configuration, when the neighboring base station is a small base station such as a femto base station or a pico base station, a shorter appropriate cycle can be selected as the cycle of the intermittent monitoring operation.

  (27) Preferably, the first setting unit performs the first setting when the transmission power of the radio signal of another radio base station apparatus other than the self reported from the radio terminal apparatus is less than a predetermined threshold. The wireless terminal device is requested to set three cycles.

  With such a configuration, when the transmission power of the neighboring base station is small, a shorter appropriate cycle can be selected as the cycle of the intermittent monitoring operation.

  (28) Preferably, the first setting unit performs the third setting when a distance between base stations of other radio base station apparatuses other than the radio base station apparatus whose presence is reported from the radio terminal apparatus is less than a predetermined threshold. Requests the wireless terminal device to set the period.

  With such a configuration, a shorter appropriate cycle can be selected as the cycle of the intermittent monitoring operation when the distance between the base stations between the neighboring base station and the other radio base station device is small.

  (29) Preferably, the first setting unit requests the wireless terminal device to set the third period when there is a lot of communication traffic in the own wireless base station device or the wireless terminal device.

  With such a configuration, when there is a lot of communication traffic in the radio base station apparatus or the radio terminal apparatus, a shorter appropriate period can be selected as the period of the intermittent monitoring operation.

  (30) Preferably, the intermittent monitoring operation is DRX (Discontinuous Reception) defined by 3GPP (Third Generation Partnership Project), and the communication control information is communication control information (Physical Downlink Control Channel defined by 3GPP). ).

  With such a configuration, in a communication system defined by 3GPP, intermittent monitoring operation can be performed at an appropriate period, and communication can be stabilized and power consumption of the wireless terminal device can be well balanced.

  (31) Preferably, the intermittent monitoring operation is DRX (Discontinuous Reception) defined by 3GPP (Third Generation Partnership Project), and the communication control information is communication control information (Physical Downlink Control Channel defined by 3GPP). ).

  With such a configuration, in a communication system defined by 3GPP, intermittent monitoring operation can be performed at an appropriate period, and communication can be stabilized and power consumption of the wireless terminal device can be well balanced.

  (32) Preferably, the intermittent monitoring operation is DRX (Discontinuous Reception) defined by 3GPP (Third Generation Partnership Project), and the communication control information is communication control information (Physical Downlink Control Channel defined by 3GPP). ).

  With such a configuration, in a communication system defined by 3GPP, intermittent monitoring operation can be performed at an appropriate period, and communication can be stabilized and power consumption of the wireless terminal device can be well balanced.

  (33) In order to solve the above-described problem, a communication control method according to an aspect of the present invention is a communication control method in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus. The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and determines an on period and the communication control information to monitor the communication control information. It is possible to perform an intermittent monitoring operation that periodically repeats an off period that does not need to be monitored. The cycle that can be set as the cycle of the intermittent monitoring operation is different from the first cycle in length, and There are a plurality of second periods that can be set to be shorter than the first period, and the wireless terminal device performs the intermittent monitoring operation in the first period; The base station apparatus, as the cycle of the intermittent monitoring operation, and a step of requesting the setting corresponding to the second cycle selected from the plurality of second cycle to said wireless terminal.

  With such a configuration, it is possible to perform an intermittent monitoring operation by selecting an appropriate period and to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner. In addition, since the radio base station apparatus is configured to select the period of the intermittent monitor operation, it is not necessary to acquire information used for selection determination of the period of the intermittent monitor operation in the radio terminal apparatus. It is no longer necessary to transmit the information.

  (34) A communication control method according to another aspect of the present invention is a communication control method in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus, The terminal apparatus communicates with the radio base station apparatus based on the communication control information received from the radio base station apparatus, and does not have to monitor the ON period during which the communication control information should be monitored and the communication control information. It is possible to perform an intermittent monitoring operation that periodically repeats the off period, and the cycle that can be set as the cycle of the intermittent monitoring operation is different from the first cycle and shorter than the first cycle. There are a plurality of second periods that can be set as described above, and the wireless terminal apparatus performs the intermittent monitoring operation in the first period; Detecting a neighboring base station that is a radio base station apparatus other than a serving base station that is a radio base station apparatus selected as a counterpart, and reporting the detected neighboring base station to the serving base station; and A step in which the serving base station determines whether or not a predetermined condition relating to a communication state of the wireless terminal device is satisfied; and the intermittent operation when the serving base station satisfies the predetermined condition for the wireless terminal device. Requesting the wireless terminal device to set the second cycle as a monitoring operation cycle; and when the wireless terminal device receives the setting request for the second cycle from the serving base station, Performing the intermittent monitoring operation and selecting the length of the second period based on the detected information on the neighboring base stations; Base station estimates the length of the second period selected by the wireless terminal device based on the information on the neighboring base station reported from the wireless terminal device, and the second period of the estimated length Transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device during the ON period.

  As described above, the intermittent monitoring operation cycle is selected based on the information on the neighboring base stations, so that even if the optimum handover timing is different in each base station, the intermittent monitoring operation is performed at an appropriate cycle to stabilize communication. And power consumption of the wireless terminal device can be well balanced. Further, the configuration in which the length of the second cycle is selected in the wireless terminal device eliminates the need for the wireless base station device to create a different command and transmit it to the wireless terminal device in the request for intermittent monitoring operation in the second cycle. Further, even if the cycle of the intermittent monitoring operation is changed in the wireless terminal device, the wireless terminal device that is performing the intermittent monitoring operation can reliably receive the communication control information, and the communication with the wireless terminal device can be continued satisfactorily. .

  (35) A communication control method according to another aspect of the present invention is a communication control method in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus, The terminal apparatus communicates with the radio base station apparatus based on the communication control information received from the radio base station apparatus, and does not have to monitor the ON period during which the communication control information should be monitored and the communication control information. It is possible to perform an intermittent monitoring operation that periodically repeats the off period, and the cycle that can be set as the cycle of the intermittent monitoring operation is different from the first cycle and shorter than the first cycle. A second period and a third period that can be set as described above, wherein the wireless terminal device performs the intermittent monitoring operation in the first period, and the wireless terminal device comprises: A step of detecting a neighboring base station that is a radio base station apparatus other than a serving base station that is a radio base station apparatus that is selected as a communication partner and reporting the detected neighboring base station to the serving base station And when the serving base station determines whether or not a predetermined condition related to a communication state of the wireless terminal device is satisfied, and when the serving base station satisfies the predetermined condition for the wireless terminal device. Requesting the wireless terminal apparatus to set the second period as a period of the intermittent monitoring operation; and detecting when the wireless terminal apparatus receives the second period setting request from the serving base station. Performing the intermittent monitoring operation in the second period or the third period selected based on the information related to the neighboring base stations, The serving base station estimates which of the second period and the third period the wireless terminal apparatus selects based on the information on the neighboring base station reported from the wireless terminal apparatus, and the estimated Transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device in the on period in the second period or the third period.

  As described above, the intermittent monitoring operation cycle is selected based on the information on the neighboring base stations, so that even if the optimum handover timing is different in each base station, the intermittent monitoring operation is performed at an appropriate cycle to stabilize communication. And power consumption of the wireless terminal device can be well balanced. Further, the configuration in which the second period or the third period is selected in the wireless terminal apparatus eliminates the need for the wireless base station apparatus to create a different command and transmit it to the wireless terminal apparatus in the request for the intermittent monitoring operation in the second period. Further, even if the cycle of the intermittent monitoring operation is changed in the wireless terminal device, the wireless terminal device that is performing the intermittent monitoring operation can reliably receive the communication control information, and the communication with the wireless terminal device can be continued satisfactorily. .

  (36) In order to solve the above problem, a communication control program according to an aspect of the present invention is a communication used in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus. A control program, wherein the radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and monitors the communication control information and the communication control information. It is possible to perform an intermittent monitoring operation that periodically repeats an off period that does not require monitoring of information, and the cycle that can be set as the cycle of the intermittent monitoring operation differs from the first cycle in length. And there are a plurality of second periods that can be set to be shorter than the first period, and the wireless terminal device is connected to the computer in the first period. A step of performing a monitoring operation, and the radio base station apparatus requests the radio terminal apparatus to set a period corresponding to the second period selected from the plurality of second periods as the period of the intermittent monitoring operation. Is a program for executing the steps to be performed.

  With such a configuration, it is possible to perform an intermittent monitoring operation by selecting an appropriate period and to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner. In addition, since the radio base station apparatus is configured to select the period of the intermittent monitor operation, it is not necessary to acquire information used for selection determination of the period of the intermittent monitor operation in the radio terminal apparatus. It is no longer necessary to transmit the information.

  (37) A communication control program according to another aspect of the present invention is a communication control program used in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus, The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor the ON period during which the communication control information should be monitored and the communication control information. It is possible to perform an intermittent monitoring operation that periodically repeats a good off period, and the cycle that can be set as the cycle of the intermittent monitoring operation is different from the first cycle and has a length different from that of the first cycle. There are a plurality of second periods that can be set to be shorter, and the wireless terminal device performs the intermittent monitoring operation in the first period on the computer. And the wireless terminal device detects a neighboring base station that is a wireless base station device other than a serving base station that is a wireless base station device that is selected as a communication partner, and the detected neighboring base station Reporting a station to the serving base station, the serving base station determining whether a predetermined condition relating to a communication state of the wireless terminal apparatus is satisfied, and the serving base station including the wireless terminal apparatus When the predetermined condition is satisfied, the step of requesting the wireless terminal device to set the second period as the period of the intermittent monitoring operation, and the wireless terminal device from the serving base station to the first Upon receiving a setting request for two cycles, the intermittent monitoring operation is performed in the second cycle, and the second cycle is performed based on the detected information on the neighboring base stations. And the serving base station estimates the length of the second period selected by the wireless terminal device based on information about the neighboring base station reported from the wireless terminal device. A program for executing the step of transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device during the ON period in the second period of the estimated length.

  As described above, the intermittent monitoring operation cycle is selected based on the information on the neighboring base stations, so that even if the optimum handover timing is different in each base station, the intermittent monitoring operation is performed at an appropriate cycle to stabilize communication. And power consumption of the wireless terminal device can be well balanced. Further, the configuration in which the length of the second cycle is selected in the wireless terminal device eliminates the need for the wireless base station device to create a different command and transmit it to the wireless terminal device in the request for intermittent monitoring operation in the second cycle. Further, even if the cycle of the intermittent monitoring operation is changed in the wireless terminal device, the wireless terminal device that is performing the intermittent monitoring operation can reliably receive the communication control information, and the communication with the wireless terminal device can be continued satisfactorily. .

  (38) A communication control program according to another aspect of the present invention is a communication control program used in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus, The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor the ON period during which the communication control information should be monitored and the communication control information. It is possible to perform an intermittent monitoring operation that periodically repeats a good off period, and the cycle that can be set as the cycle of the intermittent monitoring operation is different from the first cycle and has a length different from that of the first cycle. There are a second period and a third period that can be set to be short, and the wireless terminal device performs the intermittent monitoring operation in the first period. And detecting the neighboring base station that is a wireless base station device other than the serving base station that is the wireless base station device that the wireless terminal device has selected as a communication partner, Reporting the base station to the serving base station, the serving base station determining whether a predetermined condition relating to a communication state of the wireless terminal device is satisfied, and the serving base station comprising the wireless terminal Requesting the wireless terminal device to set the second cycle as a cycle of the intermittent monitoring operation when the predetermined condition is satisfied for the device, and the wireless terminal device from the serving base station When the second cycle setting request is received, the second cycle or the third cycle selected based on the detected information on the neighboring base stations is increased. The step of performing an intermittent monitoring operation, and the serving base station selects either the second period or the third period based on the information on the neighboring base station reported from the wireless terminal apparatus And transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device in the on period in the estimated second period or third period. It is a program.

  As described above, the intermittent monitoring operation cycle is selected based on the information on the neighboring base stations, so that even if the optimum handover timing is different in each base station, the intermittent monitoring operation is performed at an appropriate cycle to stabilize communication. And power consumption of the wireless terminal device can be well balanced. Further, the configuration in which the second period or the third period is selected in the wireless terminal apparatus eliminates the need for the wireless base station apparatus to create a different command and transmit it to the wireless terminal apparatus in the request for the intermittent monitoring operation in the second period. Further, even if the cycle of the intermittent monitoring operation is changed in the wireless terminal device, the wireless terminal device that is performing the intermittent monitoring operation can reliably receive the communication control information, and the communication with the wireless terminal device can be continued satisfactorily. .

  According to the present invention, in a communication system in which a wireless terminal device can perform an operation of intermittently stopping monitoring of communication control information from a wireless base station device, communication stability can be achieved by appropriately performing the operation. And power consumption of the wireless terminal device can be well balanced.

It is a figure which shows the structure of the radio | wireless communications system which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the radio base station apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the radio | wireless terminal apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the mode of the hand-over operation | movement in the radio | wireless communications system which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the sequence of the hand-over operation | movement in the radio | wireless communications system which concerns on the 1st Embodiment of this invention. It is a figure which shows DRX operation | movement of the radio | wireless terminal apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the detail of DRX operation | movement of the radio | wireless terminal apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows long DRX and short DRX which the radio | wireless terminal apparatus which concerns on the 1st Embodiment of this invention performs. It is a figure which shows an example of the setting parameter of DRX operation | movement of the radio | wireless terminal apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the difference in the transmission interval of the measurement result notification by the difference in the DRX cycle. It is a figure which shows the simulation result of the reception quality of the radio | wireless terminal apparatus in the radio | wireless communications system which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the control part in the radio base station apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the control part in the radio | wireless terminal apparatus which concerns on the 1st Embodiment of this invention. It is the sequence diagram which defined the procedure of the change process of the DRX period in the radio | wireless communications system which concerns on the 1st Embodiment of this invention. 3 is a flowchart defining a procedure of DRX operation in the wireless terminal device according to the first embodiment of the present invention. 7 is a flowchart defining an operation procedure when the radio base station apparatus according to the first embodiment of the present invention performs a setting request process for a DRX operation. It is a figure which shows an example of the setting parameter of DRX operation | movement of the radio | wireless terminal apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the header information of the packet which the radio base station apparatus which concerns on the 1st Embodiment of this invention transmits to a radio | wireless terminal apparatus. It is a figure which shows the response | compatibility with DRX operation | movement by each radio | wireless base station apparatus which concerns on the 1st Embodiment of this invention, and each layer in a communication protocol. It is a figure which shows the structure of the control part in the radio base station apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the control part in the radio | wireless terminal apparatus which concerns on the 2nd Embodiment of this invention. It is the flowchart which defined the procedure of DRX operation | movement in the radio | wireless terminal apparatus which concerns on the 2nd Embodiment of this invention. It is the flowchart which defined the operation | movement procedure at the time of the radio base station apparatus which concerns on the 2nd Embodiment of this invention performing the setting request | requirement process of DRX operation | movement. It is a figure which shows the structure of the control part in the radio base station apparatus which concerns on the 3rd Embodiment of this invention. It is a figure which shows the structure of the control part in the radio | wireless terminal apparatus which concerns on the 3rd Embodiment of this invention. It is the sequence diagram which defined the procedure of the change process of the DRX period in the radio | wireless communications system which concerns on the 3rd Embodiment of this invention. It is the flowchart which defined the operation | movement procedure at the time of the radio base station apparatus which concerns on the 3rd Embodiment of this invention performing the setting request | requirement process of DRX operation | movement. It is the sequence diagram which defined the procedure of the change process of the DRX period in the radio | wireless communications system which concerns on the 3rd Embodiment of this invention. It is the flowchart which defined the operation | movement procedure at the time of the radio base station apparatus which concerns on the 3rd Embodiment of this invention performing the setting request | requirement process of DRX operation | movement. It is a figure which shows the change process of the DRX period according to the communication traffic by the wireless base station apparatus which concerns on the 3rd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  The radio base station apparatus notifies the radio terminal apparatus of information about the cell and the neighboring cell that it forms, that is, the frequency of the radio signal and the ID (identification) of the neighboring cell. The wireless terminal device detects and measures neighboring cells based on information notified from the wireless base station device. Based on this measurement result, movement of the wireless terminal device to the neighboring cells is started. Here, “movement” of the wireless terminal device means not only handover but also through which cell the wireless terminal device in an idle state starts communication in the future, that is, when a call or data communication is started. This means selecting whether to perform communication.

  For example, when the wireless terminal device is communicating with the wireless base station device, the destination of the wireless terminal device is determined by the wireless base station device or a higher-level device in the core network. For example, when the wireless terminal device is not communicating with the wireless base station device, the wireless terminal device determines the destination of the wireless terminal device.

  In addition, handover means that a radio base station apparatus that is a communication partner of a radio terminal apparatus during a call or data communication is switched.

  The wireless terminal device is located in a cell means that the wireless terminal device selects a wireless base station device forming the cell as a communication destination and can communicate with the wireless base station device. This means that communication is in progress.

  The femtocell and access mode are described in 3GPP (Third Generation Partnership Project) SPEC TS 22.22 as follows. That is, a femto base station is a customer premises apparatus that connects a wireless terminal device connected via a wireless interface to a mobile communication carrier network using an IP backhaul.

  Further, in the femtocell access mode, the femto base station in the closed access mode provides a service only to related CSG (Closed Subscriber Group) members. The hybrid mode femto base station also provides services to the associated CSG members and CSG non-members. The femto base station in the open access mode operates as a normal base station.

  Such a 3GPP definition may also be applied to the wireless communication system according to the embodiment of the present invention.

  Further, the following definitions can be applied together with or separately from the above definitions.

  The macro base station and the pico base station are wireless base station devices that are under the management of the operator and can communicate with the wireless base station device that has contracted with the operator. Further, it is considered that the macro base station and the pico base station are basically not turned off.

  A femto base station is a radio base station apparatus that is installed mainly in an individual or corporate building and may move or be turned off depending on the circumstances of the user.

  Further, the femto base station operates in one of open / hybrid / closed access modes. When the femto base station operates in the closed access mode, only registered members (terminals) can be connected. When operating in the closed access mode, the service is provided only to registered members. When operating in the hybrid mode, the service is provided to both registered members and unregistered members, that is, non-members. When operating in the open access mode, the same operation as that of the macro base station and the pico base station is performed.

<First Embodiment>
[Configuration and basic operation]
FIG. 1 is a diagram showing a configuration of a wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 1, a wireless communication system 301 is a mobile communication system that complies with, for example, LTE (Long Term Evolution) standardized by 3GPP (Third Generation Partnership Project), and includes femto base stations 101A, 101B, and 101C. A pico base station 101D, a macro base station 101E, and a gateway device 203 are provided.

  Hereinafter, each of the femto base stations 101A, 101B, and 101C, the pico base station 101D, and the macro base station 101E may be referred to as a radio base station apparatus 101. In FIG. 1, one macro base station, one pico base station, and three femto base stations are representatively shown, but the combination and number thereof are not limited thereto.

  The femto base stations 101A, 101B, and 101C form femtocells FCA, FCB, and FCC having a radius of several tens of meters, for example. Further, the pico base station 101D forms a picocell PC having a radius of 100 meters to 200 meters. Further, the macro base station 101E forms a macro cell MC having a radius of several kilometers, for example.

  The femto base stations 101A, 101B, and 101C are installed in places where it is difficult for the wireless terminal device 202 to receive wireless signals from the macro base station 101E and the pico base station 101D, such as an underground shopping center, and are installed in the femtocells FCA, FCB, and FCC, respectively. It is possible to communicate with the wireless terminal device 202 by transmitting and receiving wireless signals to and from the existing wireless terminal device 202.

  The pico base station 101D can communicate with the radio terminal device 202 by transmitting and receiving radio signals to and from the radio terminal device 202 existing in the pico cell PC. The macro base station 101E can communicate with the wireless terminal device 202 by transmitting and receiving wireless signals to and from the wireless terminal device 202 existing in the macro cell MC.

  The gateway device 203 performs relay processing of various communication data transmitted between the femto base stations 101A, 101B, and 101C and the host device 205 in the core network 204.

  The host device 205 is, for example, an MME (Mobility Management Entity), and manages information on the entire wireless communication system 301. For example, the upper device 205 acquires and stores information on each radio base station device in the radio communication system 301.

  Here, the direction from the wireless terminal device 202 to the core network 204 is referred to as an uplink direction, and the direction from the core network 204 to the wireless terminal device 202 is referred to as a downlink direction.

  FIG. 2 is a diagram illustrating the configuration of the radio base station apparatus according to the first embodiment of the present invention.

  Referring to FIG. 2, radio base station apparatus 101 includes antenna 91, circulator 92, radio reception unit 93, radio transmission unit 94, signal processing unit 95, and control unit 98. The signal processing unit 95 includes a reception signal processing unit 96 and a transmission signal processing unit 97. The signal processing unit 95 and the control unit 98 are realized by a CPU (Central Processing Unit) or a DSP (Digital Signal Processor).

  The circulator 92 outputs the radio signal from the radio terminal device 202 received by the antenna 91 to the radio reception unit 93 and outputs the radio signal received from the radio transmission unit 94 to the antenna 91.

  Radio receiving section 93 converts the radio signal received from circulator 92 into a baseband signal or IF (Intermediate Frequency) signal, converts the frequency-converted signal into a digital signal, and outputs the digital signal to received signal processing section 96.

  The received signal processing unit 96 performs signal processing such as despreading in the CDMA (Code Division Multiple Access) method on the digital signal received from the wireless receiving unit 93, and part or all of the digital signal after this signal processing is performed. The data is converted into a predetermined frame format and transmitted to the core network side.

  The transmission signal processing unit 97 performs IFFT (Inverse Fast Fourier Transform) in an OFDM (Orthogonal Frequency Division Multiplex) method on communication data obtained by converting communication data received from the core network side into a predetermined frame format or communication data generated by itself. The digital signal after the signal processing is output to the wireless transmission unit 94.

  The radio transmission unit 94 converts the digital signal received from the transmission signal processing unit 97 into an analog signal, converts the frequency of the converted analog signal into a radio signal, and outputs the radio signal to the circulator 92.

  The control unit 98 exchanges various information with each unit and the core network side in the radio base station apparatus 101.

  FIG. 3 is a diagram showing the configuration of the wireless terminal device according to the first embodiment of the present invention.

  With reference to FIG. 3, the wireless terminal device 202 includes an antenna 81, a circulator 82, a wireless reception unit 83, a wireless transmission unit 84, a signal processing unit 85, a control unit 88, and an input / output unit 89. Prepare. The signal processing unit 85 includes a reception signal processing unit 86 and a transmission signal processing unit 87. The signal processing unit 85 and the control unit 88 are realized by a CPU (Central Processing Unit), a DSP (Digital Signal Processor), or the like.

  Circulator 82 outputs the radio signal received from antenna 81 from radio base station apparatus 101 to radio reception unit 83, and outputs the radio signal received from radio transmission unit 84 to antenna 81.

  Radio receiving section 83 converts the radio signal received from circulator 82 into a baseband signal or IF (Intermediate Frequency) signal, converts the frequency-converted signal into a digital signal, and outputs the digital signal to received signal processing section 86.

  The received signal processing unit 86 performs signal processing such as FFT (Fast Fourier Transform) in the OFDM (Orthogonal Frequency Division Multiplex) method on the digital signal received from the wireless receiving unit 83, and outputs one of the digital signals after the signal processing. Part or all of the data is output to the control unit 88.

  The control unit 88 converts the digital signal received from the reception signal processing unit 86 into, for example, audio data and video data, and converts it into an analog signal as necessary. And the control part 88 outputs to the input-output part 89 containing a speaker, a microphone, a display, a key input device, etc.

  Further, the control unit 88 receives, for example, voice data and a control signal for controlling the wireless terminal device 202 received by the key input device from the input / output unit 89. Control unit 88 performs predetermined signal processing on the audio data and control signal received from input / output unit 89 to generate communication data, and outputs the communication data to transmission signal processing unit 87.

  The transmission signal processing unit 87 performs signal processing such as spreading processing in the CDMA (Code Division Multiple Access) system on the communication data received from the control unit 88 or communication data generated by itself, and the digital signal after this signal processing Is output to the wireless transmission unit 84.

  The wireless transmission unit 84 converts the digital signal received from the transmission signal processing unit 87 into an analog signal, converts the frequency of the converted analog signal into a wireless signal, and outputs the radio signal to the circulator 82.

  The radio base station apparatus and the radio terminal apparatus in the radio communication system according to the embodiment of the present invention read and execute a program including each step of the following sequences from a memory (not shown). This program can be installed externally. The installed program is distributed in a state stored in a recording medium, for example.

  FIG. 4 is a diagram illustrating a handover operation in the wireless communication system according to the first embodiment of the present invention. FIG. 4 shows a state in which the cells CA and CB formed by the radio base station apparatus A and the radio base station apparatus B, which are the radio base station apparatuses 101, are partially overlapped.

  FIG. 5 is a diagram showing an exemplary sequence of a handover operation in the wireless communication system according to the first embodiment of the present invention.

  Here, as shown in FIG. 4, it is assumed that the wireless terminal device 202 is located in the cell CA and is in communication with the wireless base station device A, and moves to the overlapping area of the cell CA and the cell CB. To do.

  Referring to FIG. 5, first, radio base station apparatus A sets a frequency to be measured by radio terminal apparatus 202 in communication with itself and another radio base station apparatus that transmits a radio signal of the frequency. (Step S1).

  Next, the radio base station apparatus A sends a measurement start request (Measurement Configuration) for causing the radio terminal apparatus 202 to measure the reception level of the radio signal transmitted from the other radio base station apparatus that has been set. Send. This measurement start request includes neighboring cell information, that is, the cell ID of the radio base station apparatus to be measured. Further, the measurement start request includes the transmission frequency of each radio base station device (step S2).

  Next, the radio terminal apparatus 202 receives the measurement start request from the radio base station apparatus A and starts the power measurement process (Measurement), that is, the radio indicated by the measurement start request at the frequency indicated by the received measurement start request. The received power of the radio signal transmitted from the base station apparatus is measured (step S3).

  Next, the wireless terminal device 202 transmits a measurement result notification (Measurement Report) indicating the measurement result of the received power to the wireless base station device A. For example, the wireless terminal device 202 periodically measures the received power, and when the communication state with the wireless base station device A deteriorates, and with other wireless base station devices other than the wireless base station device A When the state becomes better, a measurement result notification is transmitted to the radio base station apparatus A (step S4).

  Next, the radio base station apparatus A acquires measurement information indicating the measurement result for each cell ID based on the measurement result notification received from the radio terminal apparatus 202, and stores it in a storage unit (not shown) (step S5).

  Next, on the basis of the measurement result notification received from the wireless terminal device 202, the wireless base station device A determines whether or not the wireless terminal device 202 should be handed over. For example, the radio base station apparatus B is determined as a handover destination with reference to the information (step S6).

  Next, the radio base station apparatus A transmits a handover request indicating the radio base station apparatus B to the higher-level apparatus 205 (step S7).

  Next, the host device 205 receives the handover request from the radio base station device A, and transmits the handover request to the radio base station device B (step S8).

  Next, the radio base station apparatus B receives the handover request from the higher order apparatus 205 and transmits a handover response to the handover request to the higher order apparatus 205 (step S9).

  Next, the host device 205 receives the handover response from the radio base station device B, and transmits a handover instruction to the radio base station device A (step S10).

  Next, the radio base station apparatus A receives a handover instruction from the host apparatus 205 and transmits an RRC (Radio Resource Control) connection reconfiguration instruction (RRC Connection Reconfiguration) to the radio terminal apparatus 202 (step S11).

  Next, the radio base station apparatus A transmits a status notification indicating its own communication status to the higher level apparatus 205 (step S12).

  Next, the host device 205 receives the status notification from the radio base station device A, and transmits a status notification indicating the communication contents and the like with the radio terminal device 202 to the radio base station device B (step S13).

  Further, when the RRC connection is established between the wireless terminal device 202 and the wireless base station device B, the wireless terminal device 202 transmits an RRC connection reconfiguration complete notification (RRC Connection Reconfiguration Complete) to the wireless base station device B ( Step S14).

  Next, the radio base station apparatus B receives the RRC connection reconfiguration completion notification from the radio terminal apparatus 202 and transmits a handover completion notification to the higher-level apparatus 205 (step S15).

  Next, the host device 205 receives the handover completion notification from the radio base station device B, and transmits a terminal information release instruction to the radio base station device A (step S16).

  Next, the radio base station apparatus A receives a terminal information release instruction from the higher-level apparatus 205, releases information related to the radio terminal apparatus 202, and transmits a terminal information release completion notification to the higher-level apparatus 205 (step S17).

[DRX operation]
In the wireless communication system 301, the wireless terminal device 202 communicates with the wireless base station device 101 based on communication control information received from the wireless base station device 101, for example, PDCCH. The wireless terminal device 202 can perform an intermittent monitoring operation, for example, a DRX operation, which periodically repeats an on period in which communication control information should be monitored and an off period in which communication control information need not be monitored.

  FIG. 6 is a diagram illustrating DRX operation of the wireless terminal device according to the first embodiment of the present invention.

  Referring to FIG. 6, for example, radio terminal apparatus 202 receives a DRX operation execution instruction from radio base station apparatus 101 and monitors PDCCH from radio base station apparatus 101 for each DRX cycle Tdrx. More specifically, the radio terminal apparatus 202 monitors the PDCCH in the on period Ton and stops monitoring the PDCCH in the off period Toff in the DRX cycle Tdrx. The on period Ton corresponds to “Active Time” in LTE. Further, for example, the period in which uplink data that the wireless terminal apparatus 202 desires to transmit is “Active Time”.

  The radio base station apparatus 101 sets appropriate parameters regarding the DRX operation, for example, according to the application used by the radio terminal apparatus 202.

  For example, as a result of monitoring the PDCCH, the wireless terminal device 202 stops the operation of the transmission circuit when it is not necessary to communicate with the wireless base station device 101. That is, by executing the DRX operation, it is not necessary to continuously monitor the PDCCH, so that power consumption including the transmission circuit can be reduced.

  FIG. 7 is a diagram illustrating details of the DRX operation of the wireless terminal device according to the first embodiment of the present invention.

  Referring to FIG. 7, radio terminal apparatus 202 includes an on-period timer, a stop timer, and a retransmission timer. More specifically, the wireless terminal device 202 monitors the PDCCH until the time TM1 elapses after the on-period timer is activated. In addition, the wireless terminal device 202 monitors the PDCCH until the time TM2 elapses after the stop timer is activated. In addition, the wireless terminal device 202 monitors the PDCCH until the time TM3 elapses after the retransmission timer is activated.

  The period from the start of these timers until the time TM1, TM2 or TM3 has elapsed and timed out corresponds to the ON period.

  The on period timer is started at the start of the DRX cycle for each DRX cycle. The stop timer is started when PDCCH is received and there is uplink data or downlink data scheduled by the PDCCH, that is, transmission timing is specified, and the data is not retransmission data. Further, the retransmission timer is started regardless of whether or not uplink data or downlink data scheduled by the PDCCH, that is, transmission timing is specified, is present when the PDCCH is received, and the data is retransmission data.

  With the stop timer and the retransmission timer, it is possible to continue monitoring the PDCCH when there is a high possibility that new data to be transmitted / received is generated.

  In LTE, the on-period timer corresponds to “onDurationTimer”, the stop timer corresponds to “drx-InactivityTimer”, and the retransmission timer corresponds to “drx-RetransmissionTimer”.

  In the wireless communication system according to the first embodiment of the present invention, in the same manner as the technique described in Non-Patent Document 1, in order to suppress the occurrence of “Too Late HO”, long DRX using a normal DRX cycle is used. In addition, a short DRX having a shorter period than the long DRX is provided.

  FIG. 8 is a diagram illustrating long DRX and short DRX executed by the wireless terminal device according to the first embodiment of the present invention.

  Referring to FIG. 8, DRX operation includes long DRX and short DRX having different periods. More specifically, the long DRX cycle is LTdrx, and the short DRX cycle is STdrx smaller than LTdrx. The length of the on period of long DRX and short DRX is time TM1.

  The radio terminal apparatus 202 normally operates in long DRX, and when receiving a DRX command from the radio base station apparatus 101, the radio terminal apparatus 202 immediately switches to short DRX. The wireless terminal device 202 includes a short DRX cycle timer that is activated when a DRX command is received, and continues short DRX until the time TM4 elapses after the short DRX cycle timer is activated.

  In LTE, the short DRX cycle timer corresponds to “drxShortCycleTimer”. “DrxShortCycleTimer” can be set in the RRC layer. Once the short DRX is started, it cannot be returned to the long DRX until the short DRX cycle timer expires.

  FIG. 9 is a diagram illustrating an example of setting parameters for the DRX operation of the wireless terminal device according to the first embodiment of the present invention.

  Referring to FIG. 9, for example, radio base station apparatus 101 provides radio terminal apparatus 202 with various setting parameters related to DRX operation.

  The radio base station apparatus 101 sets “setup” when the radio terminal apparatus 202 performs the DRX operation, and sets “release” when the DRX operation is not performed.

  The length of time TM1 is set by selecting psf1 to psf200 in “onDurationTimer”. Specifically, for example, psf1 is the length of one subframe in which PDCCH exists, and the length of the subframe is 1 millisecond. That is, when PDCCH exists in each subframe, time TM1 can be set between 1 millisecond and 200 milliseconds.

  The length of time TM2 is set by selecting psf1 to psf2560 in “drx-InactivityTimer”. Specifically, when the PDCCH exists in each subframe, the time TM2 can be set between 1 ms and 2560 ms.

  The length of the time TM3 is set by selecting psf1 to psf33 in “drx-RetransmissionTimer”. Specifically, when the PDCCH exists in each subframe, the time TM3 can be set between 1 millisecond and 33 milliseconds, and is usually set to a smaller value than the time TM2.

  By selecting sf10 to sf2560 in “longDRX-CycleStartOffset”, the length of the long DRX cycle LTdrx and the subframe number at which the long DRX cycle is started are set. Specifically, the length of the long DRX cycle LTdrx can be set between 10 milliseconds and 2560 milliseconds, and the subframe number where the long DRX is started can be set between 0 and 2559. is there.

  The length of the cycle STdrx of the short DRX is set by selecting sf2 to sf640 in “shortDRX-Cycle”. Specifically, the length of the short DRX cycle STdrx can be set between 2 milliseconds and 640 milliseconds.

  By selecting 1 to 16 in “drxShortCycleTimer”, the length of the short DRX duration TM4 is set. Specifically, the length of the duration TM4 can be set between 1 cycle and 16 cycles of the short DRX.

  FIG. 10 is a diagram illustrating the difference in the transmission interval of the measurement result notification due to the difference in the DRX cycle.

  Referring to FIG. 10, in a state where the DRX operation is not performed, for example, when a measurement result notification is periodically transmitted to radio base station apparatus 101, transmission can be performed three times in a period corresponding to long DRX cycle LTdrx. Suppose that On the other hand, in the state in which long DRX is performed, since there is an off period, only one transmission in the on period can be performed.

  On the other hand, in short DRX, it is possible to report a measurement result notification once for each short DRX cycle shorter than the long DRX cycle. That is, by executing the short DRX, the transmission interval of the measurement result notification can be shortened compared to the long DRX.

[Handover issues during DRX operation in heterogeneous networks]
As described above, in the heterogeneous network, the optimum handover timing differs depending on the combination of various base stations. For example, if the short DRX cycle STdrx is lengthened, the timing of the handover operation is delayed. Therefore, the short DRX cycle STdrx needs to be adjusted to an optimal value according to the installation environment of the radio base station apparatus.

  In the technique described in Non-Patent Document 1, since there is only one setting frame for the short DRX cycle STdrx prepared in one radio base station apparatus, for example, between macro base stations or between macro base stations and pico base stations It is not possible to set a separate short DRX cycle for the handover operation.

  For this reason, in a heterogeneous network, an optimal DRX cycle cannot be set, and the frequency of handover operation failures increases, and various problems arise, such as an increase in power consumption of the wireless terminal device. Specifically, for example, if the short DRX cycle is set to be short in accordance with the femto base station or the pico base station, it becomes too short for the macro base station, and the effect of reducing power consumption becomes small.

  FIG. 11 is a diagram illustrating a reception quality simulation result of the wireless terminal device in the wireless communication system according to the first embodiment of the present invention.

  FIG. 11 shows RSSI (Received Signal Strength Indication) of the wireless terminal device 202 for 100 seconds until the wireless terminal device 202 passes near the pico base station at a speed of 30 km / hour and passes near the macro base station.

  In FIG. 11, graphs G1 and G3 indicate RSSIs of radio signals transmitted from the macro base station, and graphs G2 and G4 indicate RSSIs of radio signals transmitted from the pico base station. The graphs G1 and G2 take into account the temporal change in the received power of the radio signal in the radio terminal device 202 caused by shadowing, that is, the relative position change between the radio terminal device 202 and other objects. Simulation results, and graphs G3 and G4 are simulation results that do not consider shadowing.

  Referring to FIG. 11, the change in received power is abrupt near the radio base station apparatus, and the change in received power is gradual at a location away from the radio base station apparatus. Also, the change in received power at the cell edge is larger in the pico base station than in the macro base station.

  Therefore, in order to avoid the occurrence of “Too Late HO”, it is necessary to advance the timing of the handover operation between the macro base station and the small base station, for example, rather than the timing of the handover operation between the macro base stations.

[Detailed configuration and detailed operation]
In the radio communication system according to the first embodiment of the present invention, the above-described problem is solved by the following configuration and operation.

  In the wireless communication system 301, the period that can be set as the period of the DRX operation includes a long DRX period and a plurality of short DRX periods that have different lengths and can be set to be shorter than the long DRX period.

  That is, in the wireless communication system 301, for example, the DRX specification defined in 3GPP is expanded, and in addition to the existing short DRX, for example, an E- having a short period for small base stations such as femto base stations and pico base stations Short DRX can be set.

  FIG. 12 is a diagram illustrating a configuration of a control unit in the radio base station apparatus according to the first embodiment of the present invention.

  Referring to FIG. 12, control unit 98 includes terminal communication state determination unit 11, monitor cycle setting unit (first setting unit and second setting unit) 12, communication control unit 13, and received power information acquisition unit 14. Including.

  The monitor cycle setting unit 12 sets a setting corresponding to a short DRX cycle selected from a plurality of short DRX cycles as a cycle of the DRX operation in a state where the wireless terminal device 202 performs a DRX operation with a long DRX cycle. A request is made to the wireless terminal device 202.

  More specifically, the received power information acquisition unit 14 acquires a measurement result notification from the wireless terminal device 202 and outputs the measurement result notification to the terminal communication state determination unit 11 and the monitor cycle setting unit 12.

  Based on the measurement result notification received from the received power information acquisition unit 14, the terminal communication state determination unit 11 determines whether or not a predetermined condition regarding the communication state of the wireless terminal device 202 is satisfied, and sets the determination result as a monitor cycle Notify unit 12. For example, the terminal communication state determination unit 11 sets the predetermined condition that the presence of a radio base station apparatus 101 other than its own radio base station apparatus 101 is reported from the radio terminal apparatus 202.

  Based on the measurement result notification received from the received power information acquisition unit 14, the monitor cycle setting unit 12 sets other radio base station devices 101 other than its own radio base station device 101 to be reported from the radio terminal device 202. The wireless terminal device 202 is recognized as a neighboring base station.

  The monitor cycle setting unit 12 is used when the terminal communication state determination unit 11 determines that the predetermined condition is satisfied for the wireless terminal device 202 in a state where the wireless terminal device 202 performs the DRX operation in the long DRX cycle. Then, based on the information about the base station around the wireless terminal device 202, one of the plurality of short DRX cycles is selected. Then, the monitor cycle setting unit 12 requests the wireless terminal device 202 to set corresponding to the selected short DRX cycle as the cycle of the DRX operation.

  Specifically, for example, the monitor cycle setting unit 12 is included when the peripheral base station whose presence is reported from the wireless terminal device 202 includes small base stations such as femto base stations and pico base stations. The wireless terminal device 202 is requested to set a short DRX cycle that is shorter than the case where the wireless terminal device 202 is not connected.

  The communication control unit 13 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 during the on period in the short DRX cycle selected by the monitor cycle setting unit 12.

  Further, as described above, when time TM4 has elapsed since the start of the DRX operation with the short DRX cycle, the wireless terminal apparatus 202 resumes the DRX operation with the long DRX cycle. Accordingly, the communication control unit 13 transmits the PDCCH to the wireless terminal device so that the wireless terminal device 202 arrives in the ON period in the long DRX cycle when the time TM4 has elapsed since the start of the DRX operation of the short DRX cycle. Send to device 202.

  Note that the monitor cycle setting unit 12 is not limited to the configuration of selecting the length of the short DRX cycle based on the type of the neighboring base station, but the configuration of selecting the length of the short DRX cycle based on some information about the neighboring base station. If it is.

  For example, the monitor cycle setting unit 12 can select the length of the short DRX cycle based on the operation settings of the neighboring base stations.

  That is, the monitor cycle setting unit 12 sets a setting corresponding to a short DRX cycle selected from a plurality of short DRX cycles based on an operation setting of a neighboring base station whose presence is reported from the wireless terminal device 202. Request to 202. Specifically, for example, when the transmission power of the neighboring base station is less than a predetermined threshold, the monitor cycle setting unit 12 sets a short short DRX cycle compared to the case where the transmission power of the neighboring base station is greater than or equal to the predetermined threshold. A request is made to the wireless terminal device 202.

  Further, for example, the monitor cycle setting unit 12 can select the length of the short DRX cycle based on the installation status of the neighboring base stations.

  That is, the monitor cycle setting unit 12 sets a setting corresponding to the short DRX cycle selected from a plurality of short DRX cycles based on the installation status of the neighboring base stations whose presence is reported from the wireless terminal device 202. Request to 202. Specifically, for example, the monitor cycle setting unit 12 is equal to or greater than the predetermined threshold when the distance between the base stations of the neighboring base stations reported to be present from the wireless terminal device 202 is less than the predetermined threshold. The wireless terminal device 202 is requested to set a short DRX cycle that is shorter than the case. Here, the inter-base station distance is a distance between the surrounding base station and at least one of the other radio base station apparatuses 101 including the own radio base station apparatus 101. When the inter-base station distance is greater than or equal to a predetermined threshold, the monitor cycle setting unit 12 performs short DRX because the change in the received power of the radio terminal device 202 of the radio signal transmitted from the neighboring base station is gradual. When the distance between the base stations is less than the predetermined threshold, the received power changes rapidly, and therefore the E-short DRX is selected.

  Further, the monitor cycle setting unit 12 combines the selection criteria for the short DRX and the E-short DRX by combining all or any two of the types of the neighboring base stations, the operation settings of the neighboring base stations and the installation status of the neighboring base stations. It is also possible to do.

  FIG. 13 is a diagram illustrating a configuration of a control unit in the wireless terminal device according to the first embodiment of the present invention.

  Referring to FIG. 13, control unit 88 includes a monitor control unit 21, a communication control unit 22, a base station detection unit 23, and a received power information creation unit 24.

  The monitor control unit 21 monitors communication control information such as PDCCH from the radio base station apparatus 101, and intermittently repeats an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored. Monitor operation such as DRX operation is performed.

  The communication control unit 22 communicates with the radio base station apparatus 101 based on communication control information monitored by the monitor control unit 21, for example, PDCCH.

  In addition, the monitor control unit 21 performs a DRX operation in a long DRX cycle or a short DRX cycle according to a request from the radio base station device 101, and performs a DRX operation in a short DRX cycle according to a request from the radio base station device 101. One of a plurality of short DRX periods is set.

  More specifically, the base station detection unit 23 is a neighboring base station that is a radio base station apparatus 101 other than the serving base station that is the radio base station apparatus 101 selected by the radio terminal apparatus 202 as a communication partner. And the detected neighboring base stations are reported to the serving base station.

  Specifically, for example, the base station detection unit 23 has a reception power of a radio signal transmitted from another radio base station apparatus 101, for example, not less than −6 dB compared to a reception power of a radio signal transmitted from the serving base station. The radio base station apparatus 101 is handled as “detected”. Then, the reception power information creation unit 24 includes the reception power of the radio base station apparatus 101 detected by the base station detection unit 23 in the measurement result notification, and serves as a peripheral base station detected by the own radio terminal apparatus 202. Report to the base station.

  When performing the short DRX, the monitor control unit 21 selects any one of a plurality of short DRX periods according to a request from the serving base station based on information on the neighboring base stations detected by the base station detection unit 23. To do.

  More specifically, the period that can be set as the period of the DRX operation by the monitor control unit 21 includes the long DRX period that is set when a predetermined condition regarding the communication state of the wireless terminal device 202 is not satisfied, and the predetermined period. There are a plurality of short DRX cycles that are set when the condition is satisfied and that are different in length and can be set to be shorter than the long DRX cycle.

  The plurality of short DRX cycles include a macro base station cycle set when the base station detection unit 23 has not detected the presence of a small base station such as a femto base station or a pico base station as a neighboring base station, And a small base station cycle that is set when the presence is detected and is shorter than the macro base station cycle.

  Note that, as described in FIG. 12, the plurality of short DRX cycles are not limited to being selected based on the type of the neighboring base station, but may be selected based on some information regarding the neighboring base station.

  That is, for example, the plurality of short DRX cycles are set when the transmission power of the neighboring base stations is equal to or greater than a predetermined threshold, and when the transmission power is less than the predetermined threshold, Low power DRX cycle shorter than the power DRX cycle.

  Alternatively, for example, the plurality of short DRX cycles are set when the distance between the base stations of the neighboring base stations is equal to or greater than a predetermined threshold and when the distance is less than the predetermined threshold, And a short distance DRX cycle shorter than the long distance DRX cycle.

  FIG. 14 is a sequence diagram defining the procedure of the DRX cycle changing process in the wireless communication system according to the first embodiment of the present invention.

  Referring to FIG. 14, for example, in a state where wireless terminal apparatus 202 is performing a short DRX operation, first, wireless terminal apparatus 202 transmits a measurement result notification to a serving base station (step S51).

  Next, the serving base station refers to the measurement result notification received from the wireless terminal device 202, and based on whether the peripheral base station of the wireless terminal device 202 includes a femto base station or a pico base station, A DRX cycle setting change process is performed (step S52).

  That is, when the peripheral base station of the wireless terminal device 202 includes a femto base station or a pico base station, the serving base station indicates E (Enhanced) indicating a request for setting a short DRX cycle for a small base station. ) -DRX command is transmitted to the wireless terminal device 202. On the other hand, if the neighboring base station of the wireless terminal device 202 does not include a femto base station or a pico base station, the serving base station sends a DRX command indicating a request to set a short DRX cycle for the macro base station. It transmits to the said radio | wireless terminal apparatus 202 (step S53).

  Next, the radio | wireless terminal apparatus 202 changes a short DRX period according to the DRX command or E-DRX command received from the serving base station (step S54).

  Next, the wireless terminal device 202 transmits a measurement result notification to the serving base station. For example, when the E-DRX command is received, the wireless terminal device 202 sets the short DRX cycle STdrx to be shorter than when the DRX command is received. S55).

  Next, the serving base station determines whether or not to execute the handover operation of the wireless terminal device 202 based on the measurement result notification received from the wireless terminal device 202. The target base station that is the handover destination radio base station apparatus 101 is determined with reference to the cell information (step S56).

  Next, the serving base station transmits a handover request to the target base station via the higher-level device 205 (step S57).

  Next, the target base station receives a handover request from the serving base station via the higher-level device 205, and transmits a handover response to the handover request to the serving base station via the higher-level device 205 (step S58).

  Next, the serving base station receives a handover response from the target base station via the higher-level device 205, and transmits an RRC (Radio Resource Control) connection reconfiguration instruction (RRC Connection Reconfiguration) to the wireless terminal device 202 (step S59). ).

  FIG. 15 is a flowchart defining the procedure of the DRX operation in the wireless terminal device according to the first embodiment of the present invention.

  Referring to FIG. 15, control unit 88 performs long DRX until receiving an E-DRX command or a DRX command (NO in step S22 and NO in step S23) in a state in which the DRX operation is performed (step S21). Is continued (step S29).

  When receiving the DRX command (NO in step S22 and YES in step S23), control unit 88 starts short DRX and sets a short DRX cycle timer (step S24).

  Next, when the short DRX cycle timer expires (YES in step S25), the control unit 88 resumes long DRX (step S28).

  On the other hand, when the control unit 88 receives the E-DRX command (YES in step S22), the control unit 88 starts the E-short DRX and sets the E-short DRX cycle timer. Note that the wireless terminal device 202 is not limited to the configuration including the E-short DRX cycle timer separately, but may be configured to switch the initial value between the short DRX and the E-short DRX and share the short DRX cycle timer (step S26). ).

  Next, when the E-short DRX cycle timer expires (YES in step S27), the control unit 88 resumes long DRX (step S28).

  FIG. 16 is a flowchart defining an operation procedure when the radio base station apparatus according to the first embodiment of the present invention performs a setting request process for the DRX operation.

  Referring to FIG. 16, when receiving a measurement result notification from, for example, wireless terminal apparatus 202, control unit 98 receives a recent measurement result notification, for example, a measurement result notification received from wireless terminal apparatus 202 a predetermined time before the present time. It is confirmed whether or not the wireless base station apparatus 101 other than its own wireless base station apparatus 101, that is, the neighboring base stations are included (step S61). When a neighboring base station is included in the recent measurement result notification from the wireless terminal device 202, the control unit 98 determines that the possibility of the handover operation of the wireless terminal device 202 occurring to some extent.

  Then, the control unit 98 is a case where a neighboring base station is included in the recent measurement result notification (YES in step S61), and a small base station such as a femto base station or a pico base station is included in the neighboring base station. If not included (NO in step S62), a DRX command is transmitted to the wireless terminal device 202 (step S63).

  Next, for example, the control unit 98 sets the operation state of the wireless terminal device 202 managed in a storage unit (not shown) to short DRX. That is, the control unit 98 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 during the on period in the short DRX cycle (step S64).

  Also, the radio base station apparatus 101 includes a short DRX cycle timer as with the radio terminal apparatus 202, and the control unit 98 sets the short DRX cycle timer of the own radio base station apparatus 101 (step S65).

  Next, when the short DRX cycle timer of its own radio base station apparatus 101 expires (YES in step S65), the control unit 98 determines the operation state of the radio terminal apparatus 202 managed in a storage unit (not shown), for example. Set to long DRX. That is, the control unit 98 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 in the on period in the long DRX cycle (step S69).

  On the other hand, the control unit 98 is a case where a peripheral base station is included in the recent measurement result notification (YES in step S61), and a small base station such as a femto base station or a pico base station is included in the peripheral base station. If it is included (YES in step S62), the E-DRX command is transmitted to the wireless terminal device 202 (step S66).

  Next, the control unit 98 sets, for example, the operation state of the wireless terminal device 202 managed in a storage unit (not shown) to E-short DRX. That is, the control unit 98 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 during the on period in the short DRX cycle (step S67).

  Also, the radio base station apparatus 101 includes an E-short DRX cycle timer as in the radio terminal apparatus 202, and the control unit 98 sets the E-short DRX cycle timer of its own radio base station apparatus 101 ( Step S67).

  Next, when its own E-short DRX cycle timer expires (YES in step S68), the control unit 98 sets the operation state of the wireless terminal device 202 managed in, for example, a storage unit (not shown) to long DRX. To do. That is, the control unit 98 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 in the on period in the long DRX cycle (step S69).

  When the control unit 98 requests the wireless terminal device 202 to perform the same DRX operation as the DRX operation currently being executed by the wireless terminal device 202 for the short DRX or the E-short DRX, Set again. On the other hand, when requesting the DRX operation different from the DRX operation currently being executed by the wireless terminal device 202 to the wireless terminal device 202, the control unit 98 stops the timer in use and newly requests it. A timer corresponding to the DRX operation is set, and a command corresponding to the wireless terminal device 202 is transmitted.

  As described above, the configuration in which the wireless base station device 101 requests the setting related to the short DRX operation for the small base station eliminates the need for the wireless terminal device 202 to recognize the type of the wireless base station device 101. For example, the serving base station Therefore, it is not necessary to transmit a list indicating the types of neighboring base stations to the wireless terminal device 202.

  FIG. 17 is a diagram illustrating an example of setting parameters for the DRX operation of the wireless terminal device according to the first embodiment of the present invention.

  In the setting parameters shown in FIG. 17, “enhancedshortDRX-Cycle” and “drxenhanced ShortCycleTimer”, which are parameters for E-short DRX, are added to the setting parameters shown in FIG. 9.

  The length of the period STdrx of the E-short DRX is set by selecting sf2 to sf640 in “enhancedshortDRX-Cycle”. Specifically, the length of the period STdrx of the E-short DRX can be set between 2 milliseconds and 640 milliseconds.

  The length of the duration TM4 of the E-short DRX is set by selecting 1 to 16 in “drxenhanced ShortCycleTimer”. Specifically, the length of the duration TM4 can be set between 1 cycle and 16 cycles of the E-short DRX.

  The settable values of the above two parameters are the same as those of “shortDRX-Cycle” and “drxShortCycleTimer”, which are parameters for short DRX, but are set smaller than the parameters for short DRX. Further, a configuration in which a settable value at which the E-short DRX parameter is smaller than the short DRX parameter may be provided from the beginning.

  FIG. 18 is a diagram illustrating an example of header information of a packet transmitted from the wireless base station device according to the first embodiment of the present invention to the wireless terminal device.

  Referring to FIG. 18, control unit 98, for example, reserves bits in the header of the MAC packet indicated in “Values of LCID for DL-SCH” in 3GPP TS36.321 v10.4 Table 6.2.1-1. Assign for E-DRX command. Specifically, an E-DRX command is assigned to Index “11010”.

  FIG. 19 is a diagram illustrating a correspondence between the DRX operation and each layer in the communication protocol by the radio base station apparatus according to the first embodiment of the present invention.

  Referring to FIG. 19, radio base station apparatus 101 has, for example, an RRC layer, a PDCP (Packet Data Convergence Protocol) layer, an RLC (Radio Link Control) layer, a MAC layer, a PHY layer, and an RF (Radio Frequency) layer. Operates according to the communication protocol. Here, the RRC layer is the highest layer and the RF layer is the lowest layer.

  That is, the monitor cycle setting unit 12 requests the wireless terminal device 202 to set the cycle of the DRX operation according to the MAC layer, and the long DRX cycle, the short DRX cycle, and the E-short DRX cycle as the requested cycle. Can be switched. Further, the monitor cycle setting unit 12 can select the short DRX cycle and the E-short DRX cycle length according to the RRC layer higher than the MAC layer.

  Since the setting value changing process of the cycle STdrx of the short DRX and the E-short DRX corresponds to the RRC layer, the radio base station apparatus 101 performs the RRC layer, the PDCP layer, the RLC layer, the MAC layer, the PHY as indicated by the arrow R1. Messages such as requests and responses are exchanged with the wireless terminal device 202 in the layer and the RF layer, respectively.

  Also, the long DRX, short DRX, and E-short DRX switching processing for the wireless terminal device 202 corresponds to the MAC layer. For this reason, the radio base station apparatus 101 exchanges messages such as requests and responses with the radio terminal apparatus 202 in the MAC layer, the PHY layer, and the RF layer, respectively, as indicated by the arrow R2.

  For this reason, the switching process of long DRX, short DRX, and E-short DRX for wireless terminal apparatus 202 does not require time as compared with the setting value changing process of cycle STdrx of short DRX and E-short DRX, and in a short cycle. Can be changed.

  As described above, by effectively utilizing lower layer information, it is possible to perform a quick and appropriate DRX operation switching process following a change in the communication environment of the wireless terminal device 202 and the wireless base station device 101.

  By the way, in a heterogeneous network that is a communication system in which femto base stations, pico base stations, and macro base stations are mixed, for example, a plurality of femto cells or pico cells are formed in a macro cell. For this reason, handover of the wireless terminal device is likely to occur, and the situation of performing handover is complicated. That is, in a heterogeneous network, the optimal handover timing differs depending on the combination of various base stations, and therefore it is difficult to set an optimal DRX cycle fixedly. When an inappropriate DRX cycle is set, various problems such as an increased frequency of failed handover operations and an increase in power consumption of the wireless terminal device occur.

  On the other hand, in the radio base station apparatus according to the first embodiment of the present invention, the period that can be set as the period of the DRX operation is different from the long DRX period and shorter than the long DRX period. There are a plurality of short DRX periods that can be set as follows. The radio base station apparatus 101 sets a setting corresponding to a short DRX cycle selected from a plurality of short DRX cycles as a cycle of the DRX operation in a state where the radio terminal device 202 performs a DRX operation with a long DRX cycle. A request is made to the wireless terminal device 202.

  With such a configuration, it is possible to perform DRX operation by selecting an appropriate cycle, and to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner. In addition, the configuration in which the radio base station apparatus 101 selects the DRX operation cycle eliminates the need for the radio terminal apparatus 202 to acquire information used for the DRX cycle selection determination. It is no longer necessary to transmit the information.

  In the radio communication system according to the first embodiment of the present invention, the radio base station apparatus 101 communicates with the radio terminal apparatus 202 in a state where the radio terminal apparatus 202 performs the DRX operation in the long DRX cycle. When a predetermined condition related to the state is satisfied, the DRX operation period is determined based on information on the radio base station apparatus 101 other than the self that is reported from the radio terminal apparatus 202, among a plurality of short DRX periods. A setting corresponding to the short DRX cycle selected from is requested to the wireless terminal device 202.

  As described above, the configuration in which the cycle of the DRX operation is selected based on the information related to the neighboring base station that is the radio base station device 101 other than itself, for example, even when the optimum handover timing is different in each base station, at an appropriate cycle. DRX operation can be performed. In addition, the configuration in which the radio base station apparatus 101 selects the cycle of the DRX operation eliminates the need for the radio terminal apparatus 202 to acquire information on neighboring base stations. There is no need to transmit the information.

  Further, in the radio communication system according to the first embodiment of the present invention, radio base station apparatus 101 is based on the type of radio base station apparatus 101 other than itself that is reported from radio terminal apparatus 202. A setting corresponding to the short DRX cycle selected from the plurality of short DRX cycles is requested to the wireless terminal device 202.

  With such a configuration, it is possible to select a DRX operation cycle based on an appropriate reference based on the type of the surrounding base station.

  Further, in the radio communication system according to the first embodiment of the present invention, radio base station apparatus 101 is based on the operation settings of other radio base station apparatus 101 other than itself, whose existence is reported from radio terminal apparatus 202. The wireless terminal device 202 is requested to set corresponding to the short DRX cycle selected from the plurality of short DRX cycles.

  With this configuration, it is possible to select a DRX operation cycle based on an appropriate reference based on the operation settings of neighboring base stations.

  Further, in the radio communication system according to the first embodiment of the present invention, the radio base station apparatus 101 is based on the installation status of other radio base station apparatuses 101 other than the radio base station apparatus 202 whose existence is reported from the radio terminal apparatus 202. The wireless terminal device 202 is requested to set corresponding to the short DRX cycle selected from the plurality of short DRX cycles.

  With such a configuration, it is possible to select the period of the DRX operation based on an appropriate standard based on the installation status of the neighboring base stations.

  Also, in the radio communication system according to the first embodiment of the present invention, the radio base station apparatus 101 reports that the radio terminal apparatus 202 reports the presence of another radio base station apparatus 101 other than itself. Condition.

  With such a configuration, when the possibility that the handover operation of the wireless terminal device 202 is executed becomes high to some extent, switching from long DRX to short DRX or E-short DRX can be appropriately performed.

  Further, in the radio communication system according to the first embodiment of the present invention, radio base station apparatus 101 has a case where a small base station is included in the neighboring base stations whose existence is reported from radio terminal apparatus 202. The wireless terminal device 202 is requested to set a short DRX cycle that is shorter than the case where it is not included.

  With such a configuration, when the neighboring base station is a small base station such as a femto base station or a pico base station, a shorter appropriate period can be selected as the period of the DRX operation.

  Also, in the radio communication system according to the first embodiment of the present invention, the radio base station apparatus 101 has a predetermined transmission power of radio signals of other radio base station apparatuses 101 reported to exist by the radio terminal apparatus 202. Is less than the predetermined threshold, the wireless terminal device 202 is requested to set a short DRX cycle that is shorter than that when the predetermined threshold is exceeded.

  With such a configuration, when the transmission power of the neighboring base station is small, a shorter appropriate cycle can be selected as the cycle of the DRX operation.

  Further, in the radio communication system according to the first embodiment of the present invention, the radio base station apparatus 101 has a predetermined distance between base stations of other radio base station apparatuses 101 whose existence is reported from the radio terminal apparatus 202. When it is less than the threshold value, the wireless terminal device 202 is requested to set a short DRX cycle that is shorter than when it is equal to or greater than the predetermined threshold value.

  With such a configuration, a shorter appropriate cycle can be selected as the cycle of the DRX operation when the inter-base station distance between the neighboring base station and another radio base station device is small.

  Further, in the radio communication system according to the first embodiment of the present invention, radio base station apparatus 101 transmits the PDCCH to the radio terminal apparatus 202 so as to arrive at radio terminal apparatus 202 during the ON period in the selected short DRX cycle. 202.

  With such a configuration, even if the cycle of the DRX operation is changed, the wireless terminal device 202 during the DRX operation can reliably receive the PDCCH, and communication with the wireless terminal device 202 can be favorably continued.

  Also, the radio base station apparatus according to the first embodiment of the present invention arrives at radio terminal apparatus 202 in the on period in the long DRX cycle when time TM4 has elapsed since the start of the DRX operation in the short DRX cycle. As described above, the PDCCH is transmitted to the wireless terminal device 202.

  With this configuration, even when the wireless terminal device 202 autonomously switches from short DRX to long DRX, the wireless terminal device 202 during DRX operation can reliably receive the PDCCH, and Communication can be continued well.

  Further, in the radio base station apparatus according to the first embodiment of the present invention, the monitor cycle setting unit 12 performs the DRX operation cycle when the radio terminal device 202 performs the DRX operation in the long DRX cycle. A setting corresponding to the short DRX cycle selected from the plurality of short DRX cycles is requested to the wireless terminal device 202.

  With such a configuration, it is possible to perform DRX operation by selecting an appropriate cycle, and to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner. In addition, the configuration in which the radio base station apparatus 101 selects the DRX operation cycle eliminates the need for the radio terminal apparatus 202 to acquire information used for the DRX cycle selection determination. It is no longer necessary to transmit the information.

  Further, in the radio terminal apparatus according to the first embodiment of the present invention, the monitor control unit 21 performs DRX operation with a long DRX cycle or a short DRX cycle according to a request from the radio base station device 101, and with a short DRX cycle. When performing the DRX operation, one of a plurality of short DRX cycles is set according to a request from the radio base station apparatus 101.

  With such a configuration, it is possible to perform DRX operation by selecting an appropriate cycle, and to stabilize communication and suppress power consumption of the wireless terminal device in a well-balanced manner. In addition, the configuration in which the radio base station apparatus 101 selects the DRX operation cycle eliminates the need for the radio terminal apparatus 202 to acquire information used for the DRX cycle selection determination. It is no longer necessary to transmit the information.

  In the wireless terminal device according to the first embodiment of the present invention, the period that can be set as the DRX operation period by the monitor control unit 21 satisfies a predetermined condition regarding the communication state of the wireless terminal device 202 of itself. There are a long DRX cycle that is set when there is not, and a plurality of short DRX cycles that are set when the predetermined condition is satisfied and that are different in length and can be set to be shorter than the long DRX cycle. The plurality of short DRX cycles are the macro base station cycle set when the base station detection unit 23 does not detect the presence of a small base station as a neighboring base station, and the presence of the macro DR. And a cycle for a small base station that is shorter than the cycle for a macro base station.

  As described above, even when the optimum handover timing is different in each base station, the DRX operation period can be set as a period having different lengths based on whether or not the neighboring base station is a small base station. Therefore, the DRX operation can be performed at an appropriate period to stabilize the communication and suppress the power consumption of the wireless terminal device in a well-balanced manner.

  In the wireless terminal device according to the first embodiment of the present invention, the period that can be set as the DRX operation period by the monitor control unit 21 satisfies a predetermined condition regarding the communication state of the wireless terminal device 202 of itself. There are a long DRX cycle that is set when there is not, and a plurality of short DRX cycles that are set when the predetermined condition is satisfied and that are different in length and can be set to be shorter than the long DRX cycle. The plurality of short DRX cycles are less than the predetermined threshold and the high power DRX cycle set when the transmission power of the neighboring base station detected by the base station detection unit 23 is equal to or higher than the predetermined threshold. A low power DRX cycle that is set in some cases and shorter than the high power DRX cycle.

  As described above, the DRX operation cycle can be set to a cycle having different lengths based on the magnitude of the transmission power of the neighboring base stations. For example, even when the optimum handover timing is different in each base station, an appropriate cycle can be set. Therefore, the DRX operation can be performed to stabilize the communication and suppress the power consumption of the wireless terminal device in a well-balanced manner.

  In the wireless terminal device according to the first embodiment of the present invention, the period that can be set as the DRX operation period by the monitor control unit 21 satisfies a predetermined condition regarding the communication state of the wireless terminal device 202 of itself. There are a long DRX cycle that is set when there is not, and a plurality of short DRX cycles that are set when the predetermined condition is satisfied and that are different in length and can be set to be shorter than the long DRX cycle. The plurality of short DRX cycles include the long-distance DRX cycle set when the distance between the base stations of the neighboring base stations detected by the base station detector 23 is equal to or greater than a predetermined threshold, and the predetermined threshold. And a short-distance DRX cycle shorter than the long-distance DRX cycle.

  In this way, the DRX operation cycle can be set to have different lengths based on the distance between the base stations between the neighboring base stations and other base stations. Even if different, the DRX operation can be performed at an appropriate period to stabilize the communication and suppress the power consumption of the wireless terminal device in a well-balanced manner.

  Moreover, in the radio base station apparatus according to the first embodiment of the present invention, the monitor cycle setting unit 12 sets the DRX operation cycle for the radio terminal device 202 according to the first layer of the plurality of layers. The long DRX cycle, the short DRX cycle, and the E-short DRX cycle can be switched as the requested cycle. Then, the monitor cycle setting unit 12 can select the short DRX cycle and the E-short DRX cycle length according to the second layer higher than the first layer among the plurality of layers.

  As described above, by effectively utilizing lower layer information, it is possible to perform a quick and appropriate DRX operation switching process following a change in the communication environment of the wireless terminal device 202 and the wireless base station device 101. Therefore, the DRX operation can be performed at an appropriate period, and communication can be stabilized and the power consumption of the wireless terminal device can be well balanced.

  In the radio base station apparatus according to the first embodiment of the present invention, the first layer is a MAC (Media Access Control) layer defined by 3GPP (Third Generation Partnership Project), and the second layer This layer is an RRC (Radio Resource Control) layer defined by 3GPP.

  With such a configuration, in a radio base station apparatus that operates in accordance with a communication protocol defined by 3GPP, DRX operation is performed at an appropriate period to achieve a stable balance of communication and suppression of power consumption of the radio terminal apparatus. it can.

  Further, in the wireless terminal device according to the first embodiment of the present invention, the monitor cycle setting unit 12 transmits to the other wireless base station device 101 other than itself, the presence of which is reported from the wireless terminal device 202 according to the MAC layer. When a small base station is included, the wireless terminal apparatus 202 is requested to set the period of the E-short DRX.

  With such a configuration, when the neighboring base station is a small base station such as a femto base station or a pico base station, a shorter appropriate period can be selected as the period of the DRX operation.

  Further, in the wireless terminal device according to the first embodiment of the present invention, the monitor cycle setting unit 12 of the wireless base station device 101 other than itself, whose presence is reported from the wireless terminal device 202, according to the MAC layer. When the transmission power of the radio signal is less than a predetermined threshold, the radio terminal apparatus 202 is requested to set the E-short DRX cycle.

  With such a configuration, when the transmission power of the neighboring base station is small, a shorter appropriate cycle can be selected as the cycle of the DRX operation.

  Further, in the wireless terminal device according to the first embodiment of the present invention, the monitor cycle setting unit 12 of the wireless base station device 101 other than itself, whose presence is reported from the wireless terminal device 202, according to the MAC layer. When the distance between base stations is less than a predetermined threshold, the wireless terminal device 202 is requested to set the short DRX cycle for small base stations.

  With such a configuration, a shorter appropriate cycle can be selected as the cycle of the DRX operation when the inter-base station distance between the neighboring base station and another radio base station device is small.

  In the radio communication system, radio base station apparatus, and radio terminal apparatus according to the first embodiment of the present invention, a DRX (Discontinuous Reception) operation defined by 3GPP (Third Generation Partnership Project) is performed as an intermittent monitor operation. PDCCH (Physical Downlink Control Channel) defined by 3GPP is used as communication control information.

  With such a configuration, in the communication system defined by 3GPP, DRX operation can be performed at an appropriate period, and communication can be stabilized and power consumption of the wireless terminal device can be well balanced.

  In the wireless communication system according to the first embodiment of the present invention, a plurality of lengths can be selected as the cycle of the short DRX and the cycle of the E-short DRX, but the present invention is not limited to this. is not. The E-short DRX cycle may be set shorter than the short DRX cycle, and a plurality of lengths may not be selectable. For example, a plurality of lengths may be selected for the cycle of the short DRX, while a plurality of lengths may not be selected for the cycle of the E-short DRX.

  Further, in the wireless communication system according to the first embodiment of the present invention, the DRX operation is configured such that long DRX, short DRX, and E-short DRX can be selected. However, the present invention is not limited to this. . In addition to these DRX operations, a configuration in which DRX operations having different period lengths can be selected may be employed. For example, the configuration may be such that a DRX operation with a different period length can be selected in a pico base station and a femto base station.

  Further, in the radio communication system according to the first embodiment of the present invention, radio terminal apparatus 202 is configured to resume long DRX after a predetermined time has elapsed since the start of short DRX or E-short DRX. However, the present invention is not limited to this. For example, radio terminal apparatus 202 may be configured to switch from short DRX or E-short DRX to long DRX in accordance with an instruction from radio base station apparatus 101.

  In the radio communication system according to the first embodiment of the present invention, the radio base station apparatus 101 is configured to determine the length of the long DRX cycle. However, the present invention is not limited to this. The wireless terminal device 202 may be configured to determine the length of the long DRX cycle.

  In the radio communication system according to the first embodiment of the present invention, the radio base station apparatus 101 sets the long DRX cycle LTdrx to a value larger than the short DRX and E-short DRX cycle STdrx. Although there is, it is not limited to this. It is also possible to set the long DRX cycle LTdrx to a value smaller than the cycle STdrx of the short DRX and the E-short DRX.

  Further, in the wireless communication system according to the first embodiment of the present invention, the femto base station and the pico base station are illustrated as the small base stations, but a type of base station other than the femto base station and the pico base station is small. You may treat as a base station.

  Further, in the radio communication system according to the first embodiment of the present invention, the radio base station apparatus 101 reports that the existence of another radio base station apparatus 101 other than itself is reported from the radio terminal apparatus 202. Although the configuration is such that the switching condition is from DRX to short DRX or E-short DRX, the present invention is not limited to this. The radio base station apparatus 101 may be configured such that a certain condition regarding the communication state of itself or the radio terminal apparatus 202 is set as the switching condition.

  In the radio communication system according to the first embodiment of the present invention, the radio terminal apparatus 202 is configured to report the presence of a neighboring base station to the radio base station apparatus 101 using the measurement result notification. However, the present invention is not limited to this. The wireless terminal device 202 is not limited to the notification of the measurement result, and may be configured to transmit some information indicating the presence of the wireless base station device 101 to the wireless base station device 101.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Second Embodiment>
The present embodiment relates to a radio communication system in which a radio terminal device autonomously selects the length of a DRX cycle as compared with the radio communication system according to the first embodiment. The contents other than those described below are the same as those of the wireless communication system according to the first embodiment.

  FIG. 20 is a diagram illustrating a configuration of a control unit in the radio base station apparatus according to the second embodiment of the present invention.

  Referring to FIG. 20, control unit 98 includes a terminal communication state determination unit 11, a monitor cycle setting unit 12, a communication control unit 13, and a received power information acquisition unit 14.

  The reception power information acquisition unit 14 acquires a measurement result notification from the wireless terminal device 202 and outputs the measurement result notification to the terminal communication state determination unit 11, the monitor cycle setting unit 12, and the communication control unit 13.

  Based on the measurement result notification received from the received power information acquisition unit 14, the terminal communication state determination unit 11 determines whether or not a predetermined condition regarding the communication state of the wireless terminal device 202 is satisfied, and sets the determination result as a monitor cycle Notify unit 12. For example, the terminal communication state determination unit 11 sets the predetermined condition that the presence of a radio base station apparatus 101 other than its own radio base station apparatus 101 is reported from the radio terminal apparatus 202.

  The monitor cycle setting unit 12 and the communication control unit 13, based on the measurement result notification received from the received power information acquisition unit 14, other radios other than the own radio base station device 101 whose presence is reported from the radio terminal device 202. The base station apparatus 101 is recognized as a peripheral base station of the wireless terminal apparatus 202.

  When the wireless terminal device 202 performs the DRX operation in the long DRX cycle and the predetermined condition is satisfied for the wireless terminal device 202, the monitor cycle setting unit 12 sets the wireless terminal device as the DRX operation cycle. 202 is requested to set a normal short DRX cycle, that is, a DRX command is transmitted to the wireless terminal apparatus 202.

  FIG. 21 is a diagram illustrating a configuration of a control unit in the wireless terminal device according to the second embodiment of the present invention.

  Referring to FIG. 21, control unit 88 includes a monitor control unit 21, a communication control unit 22, a base station detection unit 23, and a received power information creation unit 24.

  The monitor control unit 21 monitors communication control information such as PDCCH from the radio base station apparatus 101, and intermittently repeats an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored. A monitor operation such as a DRX operation can be performed.

  The communication control unit 22 communicates with the radio base station apparatus 101 based on communication control information monitored by the monitor control unit 21, for example, PDCCH.

  The base station detection unit 23 detects a neighboring base station that is a radio base station apparatus 101 other than the serving base station that is the radio base station apparatus 101 selected by the radio terminal apparatus 202 as a communication partner.

  In a state where the DRX operation is performed in the long DRX cycle, when the monitor control unit 21 receives a normal short DRX cycle setting request, that is, a DRX command from the serving base station, the monitor control unit 21 performs the DRX operation in the short DRX cycle. In addition, the monitor control unit 21 selects the length of the short DRX cycle based on the information regarding the neighboring base stations detected by the base station detection unit 23.

  That is, when the monitor control unit 21 receives the setting request of the normal short DRX cycle from the serving base station in the state of performing the DRX operation with the long DRX cycle, the peripheral base station detected by the base station detection unit 23 The DRX operation is performed in the normal short DRX cycle or the E-short DRX cycle selected based on the information regarding.

  Referring to FIG. 20 again, the communication control unit 13 determines the length of the short DRX cycle when the wireless terminal device 202 performs the DRX operation based on the information about the neighboring base station reported from the wireless terminal device 202. presume. Then, the communication control unit 13 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 in the on period in the short DRX cycle having the estimated length.

  In addition, the communication control unit 13 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 in the on period in the long DRX cycle when the time TM4 has elapsed after starting the DRX operation of the short DRX cycle. Send.

  FIG. 22 is a flowchart defining the procedure of the DRX operation in the wireless terminal device according to the second embodiment of the present invention.

  Referring to FIG. 22, control unit 88 continues long DRX (step S39) until a DRX command is received (NO in step S32) in a state in which a DRX operation is performed (step S31).

  When the control unit 88 receives the DRX command (YES in step S32), the control unit 88 transmits the latest measurement result notification, for example, the measurement result notification created before the predetermined time from the present to the wireless base station apparatus 101 other than the serving base station. It is confirmed whether or not the base station is included and the peripheral base station includes small base stations such as femto base stations and pico base stations (step S33).

  When the recent measurement result notification does not include a small base station as a neighboring base station (NO in step S33), the control unit 88 starts short DRX and sets a short DRX cycle timer (step S33). S34).

  Next, when the short DRX cycle timer expires (YES in step S35), the control unit 88 resumes long DRX (step S38).

  If the recent measurement result notification includes a small base station as a neighboring base station (YES in step S33), the control unit 88 starts E-short DRX and sets the E-short DRX cycle timer. Set (step S36).

  Next, when the E-short DRX cycle timer expires (YES in step S37), the control unit 88 resumes long DRX (step S38).

  For example, the wireless terminal device 202 acquires a list indicating the types of neighboring base stations from the serving base station. When receiving a DRX command from the serving base station, the wireless terminal device 202 autonomously performs E-short DRX when detecting a small base station in the latest measurement result notification.

  This eliminates the need for the radio base station apparatus 101 to create and transmit an E-DRX command separately from the DRX command.

  FIG. 23 is a flowchart defining an operation procedure when the radio base station apparatus according to the second embodiment of the present invention performs a DRX operation setting request process.

  Referring to FIG. 23, when control unit 98 receives a measurement result notification from, for example, wireless terminal device 202, control unit 98 receives the latest measurement result notification, for example, the measurement result notification received from wireless terminal device 202 a predetermined time before now. It is confirmed whether or not the wireless base station apparatus 101 other than its own wireless base station apparatus 101, that is, the neighboring base stations are included (step S41). When a neighboring base station is included in the recent measurement result notification from the wireless terminal device 202, the control unit 98 determines that the possibility of the handover operation of the wireless terminal device 202 occurring to some extent.

  Then, the control unit 98 is a case where a neighboring base station is included in the recent measurement result notification (YES in step S41), and a small base station such as a femto base station or a pico base station is included in the neighboring base station. If not included (NO in step S42), a DRX command is transmitted to the wireless terminal device 202 (step S43).

  Next, for example, the control unit 98 sets the operation state of the wireless terminal device 202 managed in a storage unit (not shown) to short DRX. That is, the control unit 98 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 during the on period in the short DRX cycle (step S44).

  Further, the radio base station apparatus 101 includes a short DRX cycle timer as with the radio terminal apparatus 202, and the control unit 98 sets the short DRX cycle timer of its own radio base station apparatus 101 (step S45).

  Next, when the short DRX cycle timer of its own radio base station apparatus 101 expires (YES in step S45), the control unit 98 determines the operation state of the radio terminal apparatus 202 managed in a storage unit (not shown), for example. Set to long DRX. That is, the control unit 98 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 during the on period in the long DRX cycle (step S49).

  On the other hand, the control unit 98 is a case where a neighboring base station is included in the recent measurement result notification (YES in step S41), and a small base station such as a femto base station or a pico base station is included in the neighboring base station. Even if it is included (YES in step S42), a DRX command is transmitted to the wireless terminal device 202 (step S46).

  Next, the control unit 98 sets, for example, the operation state of the wireless terminal device 202 managed in a storage unit (not shown) to E-short DRX. That is, the control unit 98 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 during the on period in the short DRX cycle (step S47).

  Also, the radio base station apparatus 101 includes an E-short DRX cycle timer as in the radio terminal apparatus 202, and the control unit 98 sets the E-short DRX cycle timer of its own radio base station apparatus 101 ( Step S48).

  Next, when its own E-short DRX cycle timer expires (YES in step S48), the control unit 98 sets the operating state of the wireless terminal device 202 managed in, for example, a storage unit (not shown) to long DRX. To do. That is, the control unit 98 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 during the on period in the long DRX cycle (step S49).

  Note that the control unit 98 uses the same DRX operation as the DRX operation currently being executed by the wireless terminal device 202 for the short DRX or the E-short DRX when the wireless terminal device 202 re-executes the DRX operation. Set the timer inside again. On the other hand, when it is predicted that a DRX operation different from the DRX operation currently being executed by the wireless terminal device 202 is newly executed in the wireless terminal device 202, the control unit 98 stops the timer in use, A timer corresponding to the newly executed DRX operation is set.

  As described above, in the wireless terminal device according to the second embodiment of the present invention, the base station detection unit 23 is a serving serving as the wireless base station device 101 selected by the wireless terminal device 202 as a communication partner. A neighboring base station that is a radio base station apparatus 101 other than the base station is detected. When the monitor control unit 21 receives the setting request for the short DRX cycle from the serving base station in the state in which the DRX operation is performed in the long DRX cycle, the monitor control unit 21 performs the DRX operation in the short DRX cycle and detects by the base station detection unit 23 The length of the short DRX cycle is selected based on the information on the received neighboring base station. That is, when the monitor control unit 21 receives the setting request of the normal short DRX cycle from the serving base station in the state of performing the DRX operation with the long DRX cycle, the peripheral base station detected by the base station detection unit 23 The DRX operation is performed in the normal short DRX cycle or the E-short DRX cycle selected based on the information related to.

  As described above, the configuration in which the cycle of the DRX operation is selected based on the information on the neighboring base stations allows the DRX operation to be performed at an appropriate cycle, for example, even when the optimum handover timing is different in each base station. The power consumption of the wireless terminal device can be suppressed with a good balance.

  In addition, with the configuration in which short DRX and E-short DRX are selected in radio terminal apparatus 202, radio base station apparatus 101 creates different instructions for the short DRX request and E-short DRX request, and transmits them to radio terminal apparatus 202 There is no need to do it.

  Further, in the radio base station apparatus according to the second embodiment of the present invention, terminal communication state determining section 11 determines whether or not a predetermined condition regarding the communication state of wireless terminal apparatus 202 is satisfied. When the wireless terminal device 202 performs the DRX operation in the long DRX cycle and the predetermined condition is satisfied for the wireless terminal device 202, the monitor cycle setting unit 12 sets the wireless terminal device as the DRX operation cycle. 202 is requested to set a short DRX cycle. Then, the communication control unit 13 estimates the length of the short DRX cycle when the wireless terminal device 202 performs the DRX operation based on the information about the neighboring base station reported from the wireless terminal device 202, and the estimated length The PDCCH is transmitted to the wireless terminal apparatus 202 so that the wireless terminal apparatus 202 arrives during the ON period in the short DRX cycle.

  As described above, the configuration in which the cycle of the DRX operation is selected based on the information on the neighboring base stations allows the DRX operation to be performed at an appropriate cycle, for example, even when the optimum handover timing is different in each base station. The power consumption of the wireless terminal device can be suppressed with a good balance.

  In addition, with the configuration in which short DRX and E-short DRX are selected in radio terminal apparatus 202, radio base station apparatus 101 creates different instructions for the short DRX request and E-short DRX request, and transmits them to radio terminal apparatus 202 There is no need to do it.

  Further, even if the cycle of the DRX operation is changed in the wireless terminal device 202, the wireless terminal device 202 during the DRX operation can reliably receive the PDCCH, and communication with the wireless terminal device 202 can be continued favorably.

  Moreover, in the radio base station apparatus according to the second embodiment of the present invention, the communication control unit 13 starts the short DRX cycle DRX operation, and when the time TM4 has elapsed, The PDCCH is transmitted to the wireless terminal device 202 so as to arrive at the wireless terminal device 202.

  With this configuration, even when the wireless terminal device 202 autonomously switches from short DRX to long DRX, the wireless terminal device 202 during DRX operation can reliably receive the PDCCH, and Communication can be continued well.

  Since other configurations and operations are the same as those of the wireless communication system according to the first embodiment, detailed description thereof will not be repeated here.

  Next, another embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

<Third Embodiment>
The present embodiment relates to a radio communication system in which the DRX cycle selection criterion is changed as compared with the radio communication system according to the first embodiment. The contents other than those described below are the same as those of the wireless communication system according to the first embodiment.

  In recent years, with the spread of smartphones, various forms of communication traffic have been generated between wireless terminal devices and core networks. For example, as described in 3GPP R2-1114937 (traffic modeling), a smartphone equipped with an iOS and an Android OS may randomly generate bursty traffic. This is different from the case where traffic with a constant rate like conventional VoIP (Voice over IP) and large traffic occurs only once like FTP (File Transfer Protocol).

  Therefore, in the radio communication system according to the third embodiment of the present invention, the DRX cycle is changed according to communication traffic in radio base station apparatus 101, for example, the amount or frequency of packets arriving at radio base station apparatus 101.

  FIG. 24 is a diagram illustrating a configuration of a control unit in the radio base station apparatus according to the third embodiment of the present invention.

  Referring to FIG. 24, control unit 98 includes a monitor cycle setting unit (first setting unit and second setting unit) 12, communication control unit 13, and traffic information acquisition unit 15.

  The traffic information acquisition unit 15 monitors communication traffic in its own radio base station apparatus 101 and notifies the monitoring period setting unit 12 of the monitoring result.

  The monitor cycle setting unit 12 is one of a plurality of short DRX cycles based on the monitoring result notified from the traffic information acquisition unit 15 in a state where the wireless terminal device 202 performs the DRX operation in the long DRX cycle. Select one. Then, the monitor cycle setting unit 12 requests the wireless terminal device 202 to set corresponding to the selected short DRX cycle as the cycle of the DRX operation.

  The communication control unit 13 transmits the PDCCH to the wireless terminal device 202 so as to arrive at the wireless terminal device 202 during the on period in the short DRX cycle selected by the monitor cycle setting unit 12.

  FIG. 25 is a diagram illustrating a configuration of a control unit in the wireless terminal device according to the third embodiment of the present invention.

  Referring to FIG. 25, control unit 88 includes a monitor control unit 21 and a communication control unit 22. Note that, similarly to the radio terminal apparatus according to the first embodiment of the present invention, the control unit 88 may include a base station detection unit 23 and a reception power information creation unit 24.

  The monitor control unit 21 monitors communication control information such as PDCCH from the radio base station apparatus 101, and intermittently repeats an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored. Monitor operation such as DRX operation is performed.

  The communication control unit 22 communicates with the radio base station apparatus 101 based on communication control information monitored by the monitor control unit 21, for example, PDCCH.

  In addition, the monitor control unit 21 performs a DRX operation with a long DRX cycle or a short DRX cycle according to a request from the radio base station device 101, and also performs a DRX operation with a short DRX cycle, from the radio base station device 101 One of a plurality of short DRX periods is selected according to the request.

  The plurality of short DRX cycles are a low traffic cycle that is set when the communication traffic in the radio base station apparatus 101 is low, and a high traffic cycle that is set when the communication traffic is high and shorter than the low traffic cycle. Including.

  FIG. 26 is a sequence diagram defining the procedure of DRX cycle change processing in the wireless communication system according to the third embodiment of the present invention.

  Referring to FIG. 26, for example, in a state where radio terminal apparatus 202 is performing a short DRX operation, radio base station apparatus 101 transmits a downlink address to radio terminal apparatus 202 from an S-GW (Serving Gateway) in core network 204. A packet is received (step S71).

  Next, radio base station apparatus 101 performs a DRX cycle setting change process based on, for example, the data amount or frequency of the downlink packet obtained by the statistical process (step S72).

  That is, the radio base station apparatus 101 transmits an E-DRX command to the radio terminal apparatus 202 when the data amount or arrival frequency of the downlink packet is large. Also, the radio base station apparatus 101 transmits a DRX command to the radio terminal apparatus 202 when the data amount or the arrival frequency of the downlink packet is medium. On the other hand, when the data amount or arrival frequency of the downlink packet is small, the radio base station apparatus 101 does not transmit the DRX command and the E-DRX command (step S73).

  Next, the radio | wireless terminal apparatus 202 changes a DRX period according to the DRX command or E-DRX command received from the serving base station (step S74).

  FIG. 27 is a flowchart defining an operation procedure when the radio base station apparatus according to the third embodiment of the present invention performs the setting request process for the DRX operation.

  Referring to FIG. 27, when a downlink packet arrives from S-GW (step S81), control unit 98 in radio base station apparatus 101 stores the data buffer corresponding to radio terminal apparatus 202 that is the destination of the downlink packet. The downstream packet is stored, and the accumulation amount of the data buffer is confirmed (step S82).

  When the storage amount of the data buffer is equal to or less than the predetermined threshold A1 (NO in step S82), the control unit 98 has a small amount of communication traffic to the wireless terminal device 202. It is determined that DRX should be executed. In this case, the control unit 98 does not transmit the DRX command and the E-DRX command (step S83).

  On the other hand, when the storage amount of the data buffer is larger than the predetermined threshold A1 (YES in step S82) and not more than the threshold A2 (NO in step S84), the control unit 98 sends data to the wireless terminal device 202. Since the communication traffic is medium, the wireless terminal device 202 determines that the short DRX should be executed, and transmits a DRX command to the wireless terminal device 202 (step S85). Here, the threshold value A2 is larger than the threshold value A1.

  In addition, when the storage amount of the data buffer is larger than the predetermined threshold A1 (YES in step S82) and larger than the threshold A2 (YES in step S84), the control unit 98 communicates with the wireless terminal device 202. Since there is a lot of traffic, the wireless terminal device 202 determines that E-short DRX should be executed, and transmits an E-DRX command to the wireless terminal device 202 (step S86).

  In addition to the operation of each step shown in FIG. 27, the control unit 98 sets the operation state of the wireless terminal device 202 regarding the short DRX and the E-short DRX, as in the first embodiment of the present invention. And switching to long DRX by the DRX cycle timer (steps S64 to S69 in FIG. 16).

  The data buffer may be a reception buffer or a transmission buffer. In the case of the transmission buffer, for example, the downlink packet created by the radio base station apparatus 101 is included in the communication traffic determination target.

  Further, the control unit 98 may be configured to change the cycle of the DRX operation based on not only downlink traffic but also uplink traffic. In this case, for example, the traffic information acquisition unit 15 acquires information on uplink communication traffic in the wireless terminal device 202 from the wireless terminal device 202 and notifies the monitoring cycle setting unit 12 of the information.

  The monitor cycle setting unit 12 then selects one of a plurality of short DRX cycles based on the information notified from the traffic information acquisition unit 15 in a state where the wireless terminal device 202 performs the DRX operation with the long DRX cycle. Select one. Then, the monitor cycle setting unit 12 requests the wireless terminal device 202 to set corresponding to the selected short DRX cycle as the cycle of the DRX operation.

  FIG. 28 is a sequence diagram defining the procedure of the DRX cycle changing process in the wireless communication system according to the third embodiment of the present invention.

  Referring to FIG. 28, first, radio terminal apparatus 202 reports communication traffic from itself to radio base station apparatus 101 to radio base station apparatus 101. Specifically, in a state where the short DRX operation is performed, the wireless terminal device 202 calculates the data amount or frequency of the uplink packet by, for example, statistical processing, and transmits the uplink traffic information indicating the calculation result to the wireless base station device 101. Send. The transmission of the uplink traffic information may be regular or irregular. Further, the uplink traffic information corresponds to “Buffer Status Report” in LTE. (Step S91).

  Next, the radio base station apparatus 101 performs a DRX cycle setting change process based on the uplink traffic information received from the radio terminal apparatus 202 (step S92).

  That is, the radio base station apparatus 101 transmits an E-DRX command to the radio terminal apparatus 202 when the data amount or occurrence frequency of the uplink packet in the radio terminal apparatus 202 is large. Also, the radio base station apparatus 101 transmits a DRX command to the radio terminal apparatus 202 when the data amount or occurrence frequency of the uplink packet is medium. On the other hand, the radio base station apparatus 101 does not transmit the DRX command and the E-DRX command when the data amount or the occurrence frequency of the uplink packet is low (step S93).

  Next, the radio | wireless terminal apparatus 202 changes a DRX period according to the DRX command or E-DRX command received from the serving base station (step S94).

  FIG. 29 is a flowchart defining an operation procedure when the radio base station apparatus according to the third embodiment of the present invention performs the setting request processing for the DRX operation.

  Referring to FIG. 29, when an uplink packet occurs, the control unit 88 in the wireless terminal device 202 stores the uplink packet in the data buffer for the uplink packet, confirms the accumulation amount of the data buffer, and displays the confirmation result. It transmits to the radio base station apparatus 101 as uplink traffic information (step S101).

  Next, the control unit 98 in the radio base station apparatus 101, when the accumulation amount of the data buffer indicated by the uplink traffic information received from the radio terminal apparatus 202 is equal to or less than the predetermined threshold A1 (NO in step S102), Since there is little communication traffic in the wireless terminal device 202, the wireless terminal device 202 determines that long DRX should be executed. In this case, the control unit 98 does not transmit the DRX command and the E-DRX command (step S103).

  On the other hand, when the accumulated amount of the data buffer indicated by the uplink traffic information received from the wireless terminal device 202 is larger than the predetermined threshold A1 (YES in Step S102) and is equal to or smaller than the threshold A2 (Step S104). NO), since the communication traffic in the wireless terminal device 202 is medium, the wireless terminal device 202 determines that the short DRX should be executed, and transmits a DRX command to the wireless terminal device 202 ( Step S105). Here, the threshold value A2 is larger than the threshold value A1.

  The control unit 98 also determines that the accumulated amount of the data buffer indicated by the uplink traffic information received from the wireless terminal device 202 is larger than the predetermined threshold A1 (YES in step S102) and larger than the threshold A2 (in step S104). YES) Since there is a lot of communication traffic in the wireless terminal device 202, the wireless terminal device 202 determines that E-short DRX should be executed, and transmits an E-DRX command to the wireless terminal device 202 ( Step S106).

  In addition to the operation of each step shown in FIG. 29, the control unit 98 sets the operation state of the wireless terminal device 202 for the short DRX and the E-short DRX, as in the first embodiment of the present invention. And switching to long DRX by the DRX cycle timer (steps S64 to S69 in FIG. 16).

  FIG. 30 is a diagram illustrating DRX cycle change processing according to communication traffic by the radio base station device according to the third embodiment of the present invention.

  Referring to FIG. 30, radio base station apparatus 101 selects long DRX as the DRX operation performed by radio terminal apparatus 202 in a state where the data amount or frequency of downlink packets or uplink packets is small. The radio base station apparatus 101 selects the short DRX as the DRX operation performed by the radio terminal apparatus 202 when the data amount or frequency of the downlink packet or the uplink packet becomes medium. Then, when the data amount or frequency of the downlink packet or the uplink packet increases, the radio base station apparatus 101 selects the E-short DRX as the DRX operation performed by the radio terminal apparatus 202.

  Note that the operation of each layer in the radio base station apparatus according to the first embodiment of the present invention applies similarly to the radio base station apparatus according to the third embodiment of the present invention.

  That is, the monitor cycle setting unit 12 can select the short DRX cycle and the E-short DRX cycle length according to the RRC layer higher than the MAC layer.

  The monitor cycle setting unit 12 requests the wireless terminal device 202 to set the cycle of the DRX operation according to the MAC layer, and the long DRX cycle, the short DRX cycle for low traffic, that is, the cycle of the short DRX and the high The traffic short DRX cycle, that is, the E-short DRX cycle can be switched. Specifically, the monitor cycle setting unit 12 sets the E-short DRX cycle according to the MAC layer when the communication traffic in the radio base station device 101 or the radio terminal device 202 is large. To request.

  As described above, the radio base station apparatus according to the third embodiment of the present invention, as the period of the DRX operation, in the state where the radio terminal apparatus 202 performs the DRX operation in the long DRX cycle, A request corresponding to the short DRX cycle selected from a plurality of short DRX cycles based on communication traffic in the terminal device 202 is requested to the wireless terminal device 202.

  As described above, with the configuration in which the cycle of the DRX operation is selected based on the communication data traffic in the radio base station device 101 or the radio terminal device 202, the cycle of the DRX operation can be appropriately set according to various traffics. it can. Therefore, stable communication and suppression of power consumption of the wireless terminal device can be achieved with a good balance.

  Further, in the radio communication system according to the third embodiment of the present invention, radio terminal apparatus 202 reports communication traffic from itself to radio base station apparatus 101 to radio base station apparatus 101. The radio base station apparatus 101 performs a plurality of short-circuits based on the communication traffic reported from the radio terminal apparatus 202 as the DRX operation period in a state where the radio terminal apparatus 202 performs the DRX operation with the long DRX period. A setting corresponding to the short DRX cycle selected from the DRX cycle is requested to the wireless terminal device 202.

  With such a configuration, it is possible to acquire uplink communication traffic in the wireless terminal device 202 and appropriately set the DRX operation cycle according to the uplink communication traffic in the wireless terminal device 202.

  Further, in the wireless terminal device according to the third embodiment of the present invention, the plurality of short DRX cycles includes the low traffic cycle set when the communication traffic in itself or the wireless base station device 101 is low, and the communication It is set when there is a lot of traffic and includes a cycle for high traffic shorter than a cycle for low traffic.

  As described above, the DRX operation cycle can be appropriately set according to various traffics by using a configuration in which a cycle having a different length with respect to communication traffic can be set as the DRX operation cycle. Therefore, stable communication and suppression of power consumption of the wireless terminal device can be achieved with a good balance.

  Further, in the radio base station apparatus according to the third embodiment of the present invention, the monitor cycle setting unit 12 follows the MAC layer when there is a lot of communication traffic in the radio base station apparatus 101 or the radio terminal apparatus 202, The wireless terminal device 202 is requested to set the cycle of the E-short DRX.

  As described above, by effectively utilizing lower layer information, it is possible to perform a quick and appropriate DRX operation switching process following a change in the communication environment of the wireless terminal device 202 and the wireless base station device 101. Therefore, the DRX operation can be performed at an appropriate period, and communication can be stabilized and the power consumption of the wireless terminal device can be well balanced. In addition, when there is a lot of communication traffic in the radio base station apparatus 101 or the radio terminal apparatus 202, a shorter appropriate period can be selected as the period of the DRX operation.

  Note that it is also possible to combine communication traffic and information on neighboring base stations as selection criteria for the DRX cycle.

  Since other configurations and operations are the same as those of the wireless communication system according to the first embodiment, detailed description thereof will not be repeated here.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

11 Terminal communication state determination unit 12 Monitor cycle setting unit (first setting unit and second setting unit)
DESCRIPTION OF SYMBOLS 13 Communication control part 14 Reception power information acquisition part 15 Traffic information acquisition part 21 Monitor control part 22 Communication control part 23 Base station detection part 24 Reception power information creation part 81 Antenna 82 Circulator 83 Radio | wireless reception part 84 Radio | wireless transmission part 85 Signal processing part 86 reception signal processing unit 87 transmission signal processing unit 88 control unit 89 input / output unit 91 antenna 92 circulator 93 wireless reception unit 94 wireless transmission unit 95 signal processing unit 96 reception signal processing unit 97 transmission signal processing unit 98 control unit 101A, 101B, 101C femto base station 101D pico base station 101E macro base station 203 gateway device 301 wireless communication system

Claims (38)

A radio base station device;
A communication system comprising a wireless terminal device capable of communicating with the wireless base station device,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
The radio base station device selects the second cycle selected from the plurality of second cycles as the cycle of the intermittent monitor operation in a state where the radio terminal device performs the intermittent monitor operation in the first cycle. A communication system that requests a setting corresponding to a period to the wireless terminal device.   The wireless base station device performs the intermittent monitoring operation when a predetermined condition regarding a communication state of the wireless terminal device is satisfied in a state where the wireless terminal device performs the intermittent monitoring operation in the first period. As a period, a setting corresponding to the second period selected from the plurality of second periods based on information on another radio base station apparatus other than the self that is reported from the radio terminal apparatus is set as the period. The communication system according to claim 1, wherein a request is made to the apparatus.   The radio base station apparatus is configured to correspond to the second period selected from the plurality of second periods based on a type of a radio base station apparatus other than itself that is reported from the radio terminal apparatus. The communication system according to claim 2, wherein the wireless terminal device is requested.   The radio base station apparatus corresponds to the second period selected from the plurality of second periods based on operation settings of other radio base station apparatuses other than the radio base station apparatus whose presence is reported from the radio terminal apparatus The communication system according to claim 2 or 3, wherein a setting is requested to the wireless terminal device.   The radio base station apparatus corresponds to the second period selected from the plurality of second periods based on an installation status of other radio base station apparatuses other than the radio base station apparatus whose presence is reported from the radio terminal apparatus. The communication system according to any one of claims 2 to 4, wherein a setting is requested to the wireless terminal device.   The radio base station apparatus according to any one of claims 2 to 5, wherein the predetermined condition is that the presence of a radio base station apparatus other than itself is reported from the radio terminal apparatus. Communications system. The communication system includes a small base station and a macro base station as the radio base station device,
The radio base station apparatus has a shorter second period when a small base station is included in the other radio base station apparatus whose presence is reported from the radio terminal apparatus compared to a case where a small base station is not included. The communication system according to claim 2 or 3, wherein the wireless terminal device is requested to set the following.   The radio base station apparatus has a case where the transmission power of the radio signal of the other radio base station apparatus reported to be present from the radio terminal apparatus is less than a predetermined threshold, and is greater than or equal to the predetermined threshold. The communication system according to claim 2 or 4, wherein the wireless terminal device is requested to set the second period that is shorter than the second period.   When the distance between base stations of the other radio base station apparatus reported to be present from the radio terminal apparatus is less than a predetermined threshold, the radio base station apparatus is more than the predetermined threshold. The communication system according to claim 2, wherein the wireless terminal device is requested to set the second cycle that is short.   The radio base station apparatus transmits the communication control information to the radio terminal apparatus so that the radio base station apparatus arrives at the radio terminal apparatus during the ON period in the selected second period. The communication system according to claim 1. The wireless terminal device resumes the intermittent monitoring operation of the first cycle when a predetermined time has elapsed since the intermittent monitoring operation of the second cycle was started,
The radio base station apparatus is configured to control the communication so that the radio terminal apparatus arrives at the radio terminal apparatus during the ON period in the first period when the predetermined time has elapsed since the intermittent monitoring operation in the second period has started. The communication system according to any one of claims 1 to 10, wherein information is transmitted to the wireless terminal device.   In the state where the wireless terminal device is performing the intermittent monitoring operation in the first cycle, the wireless base station device is configured as the intermittent monitoring operation cycle based on communication traffic in itself or the wireless terminal device. The communication system according to any one of claims 1 to 11, wherein a setting corresponding to the second period selected from the second period is requested to the wireless terminal device. The wireless terminal device reports communication traffic from itself to the wireless base station device to the wireless base station device,
The radio base station apparatus requests the radio terminal apparatus to set corresponding to the second period selected from the plurality of second periods based on the communication traffic reported from the radio terminal apparatus. The communication system according to claim 12. A wireless base station device capable of communicating with a wireless terminal device,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
A communication control unit for transmitting the communication control information to the wireless terminal device;
In a state where the wireless terminal device performs the intermittent monitoring operation in the first cycle, a setting corresponding to the second cycle selected from the plurality of second cycles is set as the cycle of the intermittent monitoring operation. A radio base station apparatus comprising: a monitor cycle setting unit for making a request to the radio terminal apparatus. A wireless terminal device capable of communicating with a wireless base station device,
The communication control information from the radio base station apparatus is monitored, and an intermittent monitoring operation of periodically repeating an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored is performed. Possible monitor controls,
A communication control unit for communicating with the radio base station apparatus based on the communication control information monitored by the monitor control unit;
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
The monitor control unit performs the intermittent monitoring operation in the first period or the second period according to a request from the radio base station apparatus, and among the plurality of second periods according to a request from the radio base station apparatus A wireless terminal device that sets one of them. A wireless terminal device capable of communicating with a wireless base station device,
The communication control information from the radio base station apparatus is monitored, and an intermittent monitoring operation of periodically repeating an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored is performed. Possible monitor controls,
A communication control unit for communicating with the radio base station apparatus based on the communication control information monitored by the monitor control unit;
A base station detector for detecting a neighboring base station other than a serving base station that is a wireless base station device that is selected by the wireless terminal device as a communication partner;
The period that can be set as the period of the intermittent monitoring operation by the monitor control unit is a first period that is set when a predetermined condition relating to a communication state of its own wireless terminal device is not satisfied, and the predetermined condition is satisfied. And a plurality of second periods that are set to be different from each other and set to be shorter than the first period,
The plurality of second periods include a macro base station period that is set when the base station detection unit does not detect the presence of a small base station as the neighboring base station, and a case where the presence is detected. A wireless terminal device including a small base station cycle which is set and shorter than the macro base station cycle. A wireless terminal device capable of communicating with a wireless base station device,
The communication control information from the radio base station apparatus is monitored, and an intermittent monitoring operation of periodically repeating an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored is performed. Possible monitor controls,
A communication control unit for communicating with the radio base station apparatus based on the communication control information monitored by the monitor control unit;
A base station detector for detecting a neighboring base station other than a serving base station that is a wireless base station device that is selected by the wireless terminal device as a communication partner;
The period that can be set as the period of the intermittent monitoring operation by the monitor control unit is a first period that is set when a predetermined condition relating to a communication state of its own wireless terminal device is not satisfied, and the predetermined condition is satisfied. And a plurality of second periods that are set to be different from each other and set to be shorter than the first period,
The plurality of second periods are a period for high power set when the transmission power of the neighboring base station detected by the base station detection unit is equal to or greater than a predetermined threshold, and when the transmission period is less than the predetermined threshold A wireless terminal device including a low power cycle that is set and shorter than the high power cycle. A wireless terminal device capable of communicating with a wireless base station device,
The communication control information from the radio base station apparatus is monitored, and an intermittent monitoring operation of periodically repeating an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored is performed. Possible monitor controls,
A communication control unit for communicating with the radio base station apparatus based on the communication control information monitored by the monitor control unit;
A base station detector for detecting a neighboring base station other than a serving base station that is a wireless base station device that is selected by the wireless terminal device as a communication partner;
The period that can be set as the period of the intermittent monitoring operation by the monitor control unit is a first period that is set when a predetermined condition relating to a communication state of its own wireless terminal device is not satisfied, and the predetermined condition is satisfied. And a plurality of second periods that are set to be different from each other and set to be shorter than the first period,
The plurality of second periods are a long-distance period that is set when a distance between base stations of the neighboring base stations detected by the base station detection unit is equal to or greater than a predetermined threshold, and less than the predetermined threshold. And a short-distance cycle shorter than the long-distance cycle. A wireless terminal device capable of communicating with a wireless base station device,
The communication control information from the radio base station apparatus is monitored, and an intermittent monitoring operation of periodically repeating an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored is performed. Possible monitor controls,
A communication control unit for communicating with the radio base station apparatus based on the communication control information monitored by the monitor control unit;
The period that can be set as the period of the intermittent monitoring operation by the monitor control unit includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period. ,
The plurality of second periods are set when the communication traffic in the radio base station apparatus or the radio terminal apparatus is low, and are set when the communication traffic is high, and the low traffic period A wireless terminal device including a shorter period for high traffic. A wireless terminal device capable of communicating with a wireless base station device,
The communication control information from the radio base station apparatus is monitored, and an intermittent monitoring operation of periodically repeating an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored is performed. Possible monitor controls,
A communication control unit for communicating with the radio base station apparatus based on the communication control information monitored by the monitor control unit;
A base station detector for detecting a neighboring base station other than a serving base station that is a wireless base station device that is selected by the wireless terminal device as a communication partner;
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
The monitor control unit performs the intermittent monitoring operation in the second cycle when receiving the setting request for the second cycle from the serving base station in the state of performing the intermittent monitoring operation in the first cycle, A wireless terminal device that selects a length of the second period based on information on the neighboring base stations detected by a base station detector. A wireless terminal device capable of communicating with a wireless base station device,
The communication control information from the radio base station apparatus is monitored, and an intermittent monitoring operation of periodically repeating an on period in which the communication control information should be monitored and an off period in which the communication control information need not be monitored is performed. Possible monitor controls,
A communication control unit for communicating with the radio base station apparatus based on the communication control information monitored by the monitor control unit;
A base station detector for detecting a neighboring base station other than a serving base station that is a wireless base station device that is selected by the wireless terminal device as a communication partner;
The period that can be set as the period of the intermittent monitoring operation includes a first period and a second period and a third period that are different from each other in length and can be set to be shorter than the first period.
When the monitoring control unit receives the setting request for the second period from the serving base station in the state where the intermittent monitoring operation is performed in the first period, the neighboring base station detected by the base station detection unit A wireless terminal device that performs the intermittent monitoring operation in the second period or the third period selected based on information related to a station. A wireless base station device capable of communicating with a wireless terminal device,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
A terminal communication state determination unit for determining whether or not a predetermined condition related to the communication state of the wireless terminal device is satisfied;
In a state where the wireless terminal device is performing the intermittent monitoring operation in the first period, when the predetermined condition is satisfied for the wireless terminal device, the period of the intermittent monitoring operation is set to the wireless terminal device. A monitor cycle setting unit for requesting the setting of the second cycle;
Estimating the length of the second period when the wireless terminal device performs the intermittent monitoring operation based on information about a neighboring base station that is another wireless base station device other than itself reported from the wireless terminal device And a communication control unit for transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device during the ON period in the second period of the estimated length. apparatus. The wireless terminal device resumes the intermittent monitoring operation of the first cycle when a predetermined time has elapsed since the intermittent monitoring operation of the second cycle was started,
The communication control unit is configured to transmit the communication control information so as to arrive at the wireless terminal device during the ON period in the first cycle when the predetermined time has elapsed since the intermittent monitoring operation in the second cycle has started. 23. The radio base station apparatus according to claim 22, wherein the radio base station apparatus transmits a message to the radio terminal apparatus. A wireless base station device capable of communicating with a wireless terminal device and operating according to a communication protocol having a plurality of layers,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation is shorter than the first period and a plurality of second periods that are different in length from each other and can be set to be shorter than the first period. There is a third period that can be set to
According to the first layer of the plurality of layers, the wireless terminal apparatus is requested to set the period of the intermittent monitoring operation, and the first period, the second period, and the third period are requested as the periods. A first setting unit capable of switching between,
A radio base station apparatus comprising: a second setting unit capable of selecting a length of the second period in accordance with a second layer higher than the first layer among the plurality of layers. The first layer is a MAC (Media Access Control) layer defined by 3GPP (Third Generation Partnership Project),
The radio base station apparatus according to claim 24, wherein the second layer is an RRC (Radio Resource Control) layer defined by 3GPP. The plurality of radio base station devices include a small base station and a macro base station,
The first setting unit sets the setting of the third period to the wireless terminal device when a small base station is included in another wireless base station device other than the wireless base station device whose presence is reported from the wireless terminal device. 26. The radio base station apparatus according to claim 24 or claim 25, which makes a request to the radio base station apparatus.   The first setting unit sets the third period when the transmission power of a radio signal of a radio base station apparatus other than the radio base station apparatus whose presence is reported from the radio terminal apparatus is less than a predetermined threshold. The radio base station apparatus according to any one of claims 24 to 26, which makes a request to a radio terminal apparatus.   The first setting unit sets the third period when the distance between base stations of other radio base station apparatuses other than the self reported from the radio terminal apparatus is less than a predetermined threshold. The radio base station apparatus according to any one of claims 24 to 27, which requests the terminal apparatus.   The first setting unit requests the wireless terminal device to set the third period when there is a large amount of communication traffic in its own wireless base station device or the wireless terminal device. The radio base station apparatus according to any one of the above. The intermittent monitoring operation is DRX (Discontinuous Reception) defined by 3GPP (Third Generation Partnership Project),
The communication system according to any one of claims 1 to 13, wherein the communication control information is a PDCCH (Physical Downlink Control Channel) defined by 3GPP. The intermittent monitoring operation is DRX (Discontinuous Reception) defined by 3GPP (Third Generation Partnership Project),
The communication control information is a PDCCH (Physical Downlink Control Channel) defined by 3GPP, claim 14, claim 22, claim 23, claim 24, claim 25, claim 26, claim 27, claim, 30. The radio base station apparatus according to any one of items 28 and 29. The intermittent monitoring operation is DRX (Discontinuous Reception) defined by 3GPP (Third Generation Partnership Project),
The wireless terminal apparatus according to any one of claims 15 to 21, wherein the communication control information is a PDCCH (Physical Downlink Control Channel) defined by 3GPP. A communication control method in a communication system comprising a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
The wireless terminal device performing the intermittent monitoring operation in the first period;
The wireless base station device requesting the wireless terminal device to make a setting corresponding to the second cycle selected from the plurality of second cycles as the cycle of the intermittent monitoring operation. Control method. A communication control method in a communication system comprising a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
The wireless terminal device performing the intermittent monitoring operation in the first period;
The wireless terminal device detects a neighboring base station that is a wireless base station device other than a serving base station that is a wireless base station device that is selected as a communication partner, and the detected neighboring base station is the serving Reporting to the base station;
The serving base station determining whether a predetermined condition relating to a communication state of the wireless terminal device is satisfied;
The serving base station, when the predetermined condition is satisfied for the wireless terminal device, requesting the wireless terminal device to set the second period as the period of the intermittent monitoring operation;
When the wireless terminal device receives the setting request for the second period from the serving base station, the wireless terminal device performs the intermittent monitoring operation in the second period, and determines the length of the second period based on the detected information on the neighboring base stations. A step of selecting
The serving base station estimates the length of the second period selected by the wireless terminal device based on the information on the neighboring base station reported from the wireless terminal device, and the second of the estimated length Transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device during the ON period in a cycle. A communication control method in a communication system comprising a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a second period and a third period that are different from each other in length and can be set to be shorter than the first period.
The wireless terminal device performing the intermittent monitoring operation in the first period;
The wireless terminal device detects a neighboring base station that is a wireless base station device other than a serving base station that is a wireless base station device that is selected as a communication partner, and the detected neighboring base station is the serving Reporting to the base station;
The serving base station determining whether a predetermined condition relating to a communication state of the wireless terminal device is satisfied;
The serving base station, when the predetermined condition is satisfied for the wireless terminal device, requesting the wireless terminal device to set the second period as the period of the intermittent monitoring operation;
When the wireless terminal device receives the setting request for the second period from the serving base station, the intermittent monitoring operation is performed in the second period or the third period selected based on the detected information on the neighboring base stations. Performing steps,
Based on the information about the neighboring base station reported from the wireless terminal device, the serving base station estimates whether the wireless terminal device selects the second period or the third period. Transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device during the ON period in the second period or the third period. A communication control program used in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
On the computer,
The wireless terminal device performing the intermittent monitoring operation in the first period;
For causing the radio base station apparatus to request the radio terminal apparatus to make a setting corresponding to the second period selected from the plurality of second periods as the period of the intermittent monitoring operation. Communication control program. A communication control program used in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a plurality of second periods that are different in length and can be set to be shorter than the first period.
On the computer,
The wireless terminal device performing the intermittent monitoring operation in the first period;
The wireless terminal device detects a neighboring base station that is a wireless base station device other than a serving base station that is a wireless base station device that is selected as a communication partner, and the detected neighboring base station is the serving Reporting to the base station;
The serving base station determining whether a predetermined condition relating to a communication state of the wireless terminal device is satisfied;
The serving base station, when the predetermined condition is satisfied for the wireless terminal device, requesting the wireless terminal device to set the second period as the period of the intermittent monitoring operation;
When the wireless terminal device receives the setting request for the second period from the serving base station, the wireless terminal device performs the intermittent monitoring operation in the second period, and determines the length of the second period based on the detected information on the neighboring base stations. A step of selecting
The serving base station estimates the length of the second period selected by the wireless terminal device based on the information on the neighboring base station reported from the wireless terminal device, and the second of the estimated length A communication control program for executing the step of transmitting the communication control information to the wireless terminal device so that the wireless terminal device arrives at the wireless terminal device in the ON period in a cycle. A communication control program used in a communication system including a radio base station apparatus and a radio terminal apparatus capable of communicating with the radio base station apparatus,
The radio terminal apparatus communicates with the radio base station apparatus based on communication control information received from the radio base station apparatus, and does not monitor an ON period in which the communication control information should be monitored and the communication control information. It is possible to perform intermittent monitoring operation that periodically repeats a good off period,
The period that can be set as the period of the intermittent monitoring operation includes a first period and a second period and a third period that are different from each other in length and can be set to be shorter than the first period.
On the computer,
The wireless terminal device performing the intermittent monitoring operation in the first period;
The wireless terminal device detects a neighboring base station that is a wireless base station device other than a serving base station that is a wireless base station device that is selected as a communication partner, and the detected neighboring base station is the serving Reporting to the base station;
The serving base station determining whether a predetermined condition relating to a communication state of the wireless terminal device is satisfied;
The serving base station, when the predetermined condition is satisfied for the wireless terminal device, requesting the wireless terminal device to set the second period as the period of the intermittent monitoring operation;
When the wireless terminal device receives the setting request for the second period from the serving base station, the intermittent monitoring operation is performed in the second period or the third period selected based on the detected information on the neighboring base stations. Performing steps,
Based on the information about the neighboring base station reported from the wireless terminal device, the serving base station estimates whether the wireless terminal device selects the second period or the third period. A communication control program for executing the step of transmitting the communication control information to the wireless terminal device so as to arrive at the wireless terminal device during the ON period in the second period or the third period.

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