JP6515420B2 - Terminal device, communication control method, and program - Google Patents

Description

  The present invention relates to a terminal device, a communication control method, and a program.

  LTE-A (Advanced) is a communication standard of communication technology that is an advanced version of LTE (Long Term Evolution), which is a communication standard of the wireless communication system, and one of the technologies is a CA (Carrier Aggregation) function. The term “CA” refers to a terminal apparatus and a base station for “improvement of utilization efficiency of communication resources of the whole system (request on the base station side)” and “improvement of communication speed (request on the terminal apparatus side, request of user)”. When communicating between, it is a technology which communicates using a plurality of frequency bands simultaneously. When a terminal apparatus compatible with CA communicates with a base station in a CA compatible area, the base station requests the terminal apparatus to start CA when communication is started.

3GPP TS 36.306, Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio access capabilities, 3rd Generation Partnership Project, June 24, 2011, V 10. 2.0

  However, since the CA is started by the CA start request from the base station, when there is a CA start request from the base station, the terminal apparatus side is forced to be a CA connection. Therefore, for example, when sufficient communication resources are allocated by communication connection using one frequency band, even if there is no merit in using the CA on the terminal side, when a CA start request comes from the base station, The terminal had to force CA. As a result, the terminal apparatus can simultaneously operate a plurality of wireless communication functions although it is not necessary, and power consumption may be larger than that in the case where CA is not performed.

  The present invention has been made in view of the above points, and a terminal device, a communication control method, and a program capable of suppressing wasteful communication by simultaneously using a plurality of frequency bands and suppressing power consumption. The challenge is to provide

  The present invention has been made to solve the above-described problems, and one aspect of the present invention is a terminal apparatus capable of performing communication connection with a base station using a plurality of frequency bands simultaneously, which is used for communication. An acquisition unit for acquiring from the base station information indicating the size of the communication resource allocated to communication in the frequency band, a calculation unit for calculating the size of the communication resource necessary for communication in the own terminal device, and the acquisition unit And a communication control unit configured to control how many frequency bands are simultaneously used to perform communication connection based on the acquired information and the size of the communication resource calculated by the calculation unit.

  Further, one aspect of the present invention is a communication control method in a terminal apparatus capable of performing communication connection with a base station using a plurality of frequency bands at the same time, and an acquisition unit is assigned to communication in a frequency band used for communication. An acquisition process of acquiring information indicating the size of the communication resource from the base station, a calculation process of calculating the size of the communication resource necessary for communication in the own terminal apparatus, and the communication control section; A communication control process including controlling how many frequency bands are simultaneously used to perform communication connection based on the information acquired by the unit and the size of the communication resource calculated by the calculation unit.

  Further, according to one aspect of the present invention, a computer as a terminal device capable of performing communication connection with a base station using a plurality of frequency bands simultaneously and the size of communication resources allocated for communication in the frequency band used for communication. An acquisition procedure for acquiring information from the base station, a calculation procedure for calculating the size of communication resources necessary for communication in the own terminal device, the information acquired in the acquisition procedure, and the size of the communication resource calculated in the calculation procedure And a program for causing a communication control procedure to control how many frequency bands are simultaneously used to perform communication connection based on data.

  According to the present invention, it is possible to suppress wasteful communication by simultaneously using a plurality of frequency bands, and to reduce power consumption.

1 is a schematic block diagram showing the configuration of a mobile communication system according to an embodiment. FIG. 1 is a block diagram showing a schematic configuration of a base station according to an embodiment. The block diagram showing the schematic structure of the terminal unit by an embodiment. Explanatory drawing explaining the state of RB when the request | requirement of CA connection is denied. Explanatory drawing explaining the state of RB when the request | requirement of CA connection is permitted. The figure which shows increase of RB required by a terminal device. Explanatory drawing of the state of RB in case of releasing since CA connection is unnecessary. Explanatory drawing of the state of RB in the case of releasing since there is no effect even if CA connection is carried out. 6 is a flowchart showing an example of communication control processing according to the embodiment.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram showing the configuration of a mobile communication system 1 according to the present embodiment. The mobile communication system 1 according to the present embodiment is configured to include a plurality of base stations 10 and a terminal device 20 (mobile station device, UE (User Equipment)). Although FIG. 1 shows a base station 10-1 and a base station 10-2 as an example of a plurality of base stations 10 capable of communicating with the terminal device 20, a plurality of base stations 10 other than the illustrated base station 10 are shown. Base station 10 is present. The terminal device 20 is, for example, a multifunctional mobile phone (including a smartphone), a tablet terminal device, or the like.

  In the mobile communication system 1 of the present embodiment, as a communication method between the base station 10 and the terminal device 20, for example, the LTE-A method is adopted. In the LTE-A scheme, a cell can be regarded as a component carrier, and the terminal device 20 can perform communication by connecting to one cell, and can perform communication by performing CA connection simultaneously with a plurality of cells. Here, the cell refers to the base station 10.

  In addition, the cell at the time of the terminal device 20 performing CA connection includes one primary cell (Primary Cell; PCell) as a base and one or more secondary cells (Secondary Cell; SCell) to be added. Here, when the terminal device 20 performs CA connection, it is assumed that the base station 10-1 is a PCell, the base station 10-2 is a SCell, and radio communication is simultaneously performed using the PCell and the SCell.

  The frequency band f1 of the PCell and the frequency band f2 of the SCell may belong to the same band (band, frequency band) (such as a 2 GHz band) or may belong to different bands. In addition, collecting a plurality of cells belonging to the same band to perform CA is also called intra-band carrier aggregation, and collecting a plurality of cells belonging to different bands to perform CA It is also called inter-band carrier aggregation.

  Note that for both PCell and SCell, both the downlink that is transmission from the base station 10 to the terminal device 20 and the uplink that is transmission from the terminal device 20 to the base station 10 may be performed, or either May be performed. Moreover, although the mobile communication system 1 in the present embodiment is, for example, a frequency division duplex (FDD) system, it may be a TDD (time division duplex) system.

(Example of base station configuration)
FIG. 2 is a block diagram showing a schematic configuration of the base station 10 according to the present embodiment. The base station 10 includes a communication unit 110 and a control unit 120. The communication unit 110 includes a transmission unit 111 and a reception unit 112, and performs wireless communication with the terminal device 20 using a predetermined frequency band. For example, the communication unit 110 of the base station 10-1 and the communication unit 110 of the base station 10-2 can communicate with the terminal device 20 in different frequency bands. Here, communication of the base station 10-1 is communication using the frequency band f1, and communication of the base station 10-2 is communication using the frequency band f2. Each of the communication unit 110 of the base station 10-1 and the communication unit 110 of the base station 10-2 may communicate with the terminal device 20 in the same frequency band.

  When communication with the terminal device 20 is started via the communication unit 110, the control unit 120 responds to the connection environment (radio wave environment, number of users connected to the base station 10 (number of terminal devices), data traffic, etc.) The RB (resource block, communication resource) is allocated to the terminal device 20. RBs are not always allocated at maximum, but increase or decrease one by one according to the connection environment. Then, the control unit 120 transmits the value of the RB allocated to the terminal device 20 to the terminal device 20 via the communication unit 110.

  For example, in downlink from the base station 10 to the terminal device 20, transmission is performed using a Physical Downlink Control Channel (PDCCH). The PDCCH is used to transmit downlink control information (DCI) such as downlink assignment (also referred to as downlink assignment or downlink grant) or uplink grant. For example, the information indicating the RB to be allocated to the terminal device 20 is included in this downlink assignment, and is notified to the terminal device 20 by transmission using PDCCH.

(Example of configuration of terminal device)
FIG. 3 is a block diagram showing a schematic configuration of the terminal device 20 according to the present embodiment. The terminal device 20 includes a display unit 201, an operation reception unit 202, a terminal communication unit 210, and a terminal control unit 220.

The display unit 201 includes, for example, a liquid crystal display or an organic EL (Electro Luminescence) display, and displays a menu screen of the terminal device 20, display information received from the base station 10, and the like.
The operation reception unit 202 receives an operation input by the user, and outputs an operation input signal indicating the received operation input to the terminal control unit 220. The operation reception unit 202 may include, for example, a touch panel integrated with the display unit 201 as an operation device, in addition to various buttons and keys.

  The terminal communication unit 210 wirelessly communicates with the base station 10 using, for example, the LTE-A scheme. The terminal communication unit 210 includes, for example, N (N is a positive integer) first transmission units 211-1 to N-th transmission units 211-N and N first reception units 212-1 to 212-N reception units 212. And -N. In the following description, the first transmission unit 211-1 to the N-th transmission unit 211 -N will be referred to as a transmission unit 211 when there is no particular distinction. The first reception unit 212-1 to the N-th reception unit 212-N will be referred to as a reception unit 212 unless otherwise specified.

  The first transmission unit 211-1 to the N-th transmission unit 211-N execute transmission using different frequency bands. The first reception unit 212-1 to the N-th reception unit 212-N execute reception of different frequency bands. When performing communication by CA connection, a plurality of transmission units 211 and reception units 212 corresponding to the frequency band f1 of the PCell and the frequency band f2 of the SCell are used.

  The parts that can be shared by the first transmission unit 211-1 to the Nth transmission unit 211-N and the first reception unit 212-1 to the Nth reception unit 212-N may be shared. When transmitting and receiving using a plurality of cells in a frequency band corresponding to the transmitting unit 211 or the receiving unit 212, the transmitting unit 211 or the receiving unit 212 may be provided for each cell.

The terminal control unit 220 includes an acquisition unit 221, a calculation unit 222, and a communication control unit 223.
The acquisition unit 221 acquires, from the base station 10, information indicating the size of the RB allocated to communication in the frequency band of the cell connected for communication. For example, the acquisition unit 221 acquires, via the terminal communication unit 210, the value of the RB allocated to the terminal device 20 in the base station 10 when communication with the base station 10 is started. The calculation unit 222 calculates the value of RB necessary for communication in the terminal device 20. Here, since the value of RB necessary for communication in the terminal device 20 may change momentarily according to the amount of data transmitted or received by the terminal device 20 and may increase / decrease momentarily, it is an average value over a fixed period. . For example, the calculation unit 222 calculates the value of the RB necessary for communication in the terminal device 20 as needed at predetermined intervals, and calculates the value as an average value over a fixed period.

  The communication control unit 223 simultaneously uses several frequency bands based on the value of the RB acquired by the acquisition unit 221 and the value of the RB calculated by the calculation unit 222 (RB necessary for communication in the terminal device 20). Control whether to make communication connection. If communication connection is performed in one frequency band, does the communication control unit 223 perform CA connection based on the value of RB acquired by the acquisition unit 221 and the value of RB calculated by the calculation unit 222? Control whether or not. For example, when the communication control unit 223 determines that the RB allocated in the frequency band of one cell connected for communication is larger than the RB required for communication by the terminal device 20, a request for CA connection is received from the base station 10. Also refuse. On the other hand, if the communication control unit 223 determines that the RB allocated in the frequency band of one cell connected for communication is equal to or less than the RB required for communication by the terminal device 20, the request for CA connection from the base station 10 Allow

  When the CA connection is in progress, if the communication control unit 223 determines that the total of RBs allocated in all the frequency bands connected for communication is larger than the RB required for communication by the terminal device 20, The base station 10 rejects a request for a CA connection using more frequency bands. On the other hand, if the communication control unit 223 determines that the total of RBs allocated in all frequency bands connected for communication is equal to or less than the number of RBs required for communication by the terminal device 20, the CA connection from the base station 10 Allow the request of

  FIG. 4 is an explanatory diagram for explaining the state of the RB when the request for CA connection is rejected. “X1” indicates the number of RBs allocated to the frequency band f1 of the PCell (base station 10-1). Here, since the number of RBs to be assigned changes momentarily and momentarily increases or decreases depending on the connection environment or the like, it is an average value over a fixed period. Also, “A” indicates the number of RBs required for communication in the terminal device 20. In the illustrated example, since the number of RBs (X1) allocated to the frequency band f1 of the PCell is larger than the number of RBs required for communication (A) (X1> A), it is not necessary to perform CA. Therefore, the terminal device 20 rejects the request for CA connection from the PCell (base station 10-1), and performs communication only in the frequency band f1 of the PCell. That is, the terminal device 20 does not perform CA connection with the SCell (base station 10-2).

  FIG. 5 is an explanatory diagram for explaining the state of the RB when the request for CA connection is permitted. In the illustrated example, the number of RBs (X1) allocated to the frequency band f1 of the PCell is smaller than the number of RBs required for communication (A) (X1 <A), so there are not enough RBs. Therefore, the terminal device 20 permits the request for CA connection from the PCell (base station 10-1), adds to the frequency band f1 of the PCell, and uses the frequency band f2 of the SCell (base station 10-2) to perform CA. Make a connection. “X2” indicates the number of RBs (average value for a fixed period) allocated to the frequency band f2 of SCell. Here, the total number of RBs of the number of RBs allocated to the PCell frequency band f1 (X1) and the number of RBs allocated to the SCell frequency band f2 (X2) is required for communication by performing CA connection It becomes larger than the number of RBs (A).

  When communication control section 223 determines that the RB allocated in this frequency band during communication connection using the frequency band of one cell is equal to or less than the RB required for communication in terminal device 20, CA The connection request may be output to the base station 10. For example, the communication control unit 223 may transmit a request for CA connection to the base station 10 via the terminal communication unit 210.

  FIG. 6 is a diagram showing an increase in RB required in the terminal device 20. The illustrated example indicates that the number of RBs (A) required by the terminal device 20 has increased to (A '). For example, if the number of RBs required by the terminal device 20 (A) increases to (A ′), the communication control unit 223 may not be sufficient with the number of RBs (X1) allocated to the frequency band f1 of the PCell (X) A request for CA connection is transmitted to the base station 10 (for example, base stations 10-1 and 10-2) via X1 <A ′) and the terminal communication unit 210. As described above, when the communication control unit 223 determines that the value of the allocated RB is not sufficient because the number of RBs required by the terminal device 20 increases during the communication connection using the frequency band of one cell. , CA connection request is output to the base station 10.

  In addition, when the communication control unit 223 determines that the necessary RB is allocated only in the frequency band of a part of connected cells during the CA connection, the RB can be sufficiently secured without the CA connection. A request to release communication connection with a cell using a frequency band other than the partial frequency band is output to the base station. For example, the communication control unit 223 transmits a request for releasing the CA connection to the base station 10 via the terminal communication unit 210.

  FIG. 7 is an explanatory diagram for explaining the state of the RB in the case of releasing because the CA connection is not necessary. In the example illustrated, the connection environment and the state of the terminal device 20 change during CA connection using the number of RBs (X1) in the frequency band f1 of PCell and the number of RBs (X2) in the frequency band f2 of SCell. The case where the number of RBs (A) required for communication in the terminal device 20 is sufficient with only the number of RBs (X1) allocated to f1 (X1> A) is shown. In this case, the terminal device 20 can secure sufficient RBs only with the number of RBs (X1) allocated in the frequency band f1 of the PCell, and the need for the number of RBs allocated (X2) in the frequency band f2 of the SCell Absent. Therefore, the terminal device 20 releases the CA connection in the frequency band f2 of the SCell.

  If there is a frequency band in which the size of the allocated RB is less than a predetermined value among the frequency bands in the CA connection during the CA connection, the communication control unit 223 communicates with the cell using the frequency band. A request to release the connection may be output to the base station 10. Here, the predetermined value is, for example, the number of RBs (hereinafter also referred to as “minimum RB number (B)”) that is extremely small relative to the number of RBs necessary for communication (A) and can be almost ignored. For example, if there is a frequency band with the number of RBs smaller than the minimum number of RBs (B) among the frequency bands connected by CA, the communication control unit 223 has no effect even if CA connection is made, so the terminal communication unit A request to release the CA connection is sent to the base station 10 via 210.

  FIG. 8 is an explanatory diagram for explaining the state of the RB in the case of releasing because there is no effect even if CA connection is made. In the example shown in the figure, during the CA connection using the number of RBs (X1) in the frequency band f1 of the PCell and the number of RBs (X2) in the frequency band f2 of the SCell, the number of RBs (X2) in the frequency band f2 is the minimum number of RBs (B) shows a case smaller than (B) (X2 <B). In this case, the terminal device 20 releases the CA connection in the frequency band f2 of the SCell because the number of RBs (X2) allocated in the frequency band f2 of the SCell is so small as to be wasted as it is connected.

  When it is determined that the allocated RB is not sufficient during the CA connection, the communication control unit 223 outputs, to the base station 10, a request to simultaneously perform CA connection using another frequency band. That is, the communication control unit 223 may perform CA connection using three or more frequency bands when the terminal device 20 can not secure an RB necessary for communication during CA connection.

<Operation of communication control process>
Next, with reference to FIG. 9, the operation of the communication control process according to the present embodiment will be described.
FIG. 9 is a flowchart showing an example of communication control processing according to the present embodiment. In this figure, when the terminal device 20 receives (downloads) data from the base station 10, communication control processing for controlling whether or not to perform CA connection is shown, but the terminal device 20 sends data to the base station 10 Even when transmitting (uploading), it is possible to control whether or not to make a CA connection by replacing reception of data with transmission.

  (Step S101) First, when communication is started, the terminal device 20 determines whether there is data to be received. If there is no data to be received (step S101: NO), the terminal device 20 ends the communication. On the other hand, when there is data to be received (step S101: YES), the terminal device 20 acquires the value of the RB allocated in the frequency band f1 of the PCell from the base station 10-1 when starting communication. . For example, the terminal device 20 acquires information on the maximum number of RBs allocated and the number of RBs actually allocated (X1). Then, the process proceeds to step S102.

  For example, when LTE band 1 (2 GHz band) is 5 MHz or 10 MHz or 15 MHz or 20 MHz, the maximum number of RBs is determined to be 25, 50, 75, and 100, respectively. Among the maximum number of RBs, RBs are allocated, and the number of RBs allocated is increased or decreased depending on the connection environment. The terminal device 20 receives the information on the value of the RB from the base station 10 every about 1 msec, so it can arbitrarily determine the average value for a fixed period.

  (Step S102) The terminal device 20 compares the allocated number of RBs (X1) with the number of RBs required for communication in the terminal device 20 (A), and the allocated number of RBs (X1) is required for communication. It is determined whether it is larger than the number of RBs (A). If the terminal device 20 determines that the allocated number of RBs (X1) is larger than the number of RBs required for communication (A) (step S102: YES), the process proceeds to step S103. On the other hand, when the terminal device 20 determines that the allocated number of RBs (X1) is equal to or less than the number of RBs necessary for communication (A) (step S102: NO), the process proceeds to step S106.

  (Step S103) Since the terminal device 20 does not need to perform CA, it rejects the request for CA connection from the base station 10-1 (see FIG. 4). Thereby, the terminal device 20 executes communication in the frequency band f1 of the PCell. Then, the process proceeds to step S104.

  During communication without CA connection, the number of RBs required for communication may change momentarily depending on the operation state of the terminal device 20. For example, when the terminal device 20 newly starts downloading or uploading data or newly starts an application, additional RBs may be required. Alternatively, the application being executed may end and the RB used by the application may not be necessary.

(Step S104)
Therefore, the terminal device 20 determines the number of required RBs of the previous time (A) and the number of required RBs of the current time (A ′) in order to confirm whether the RBs necessary for communication have changed. It is determined whether or not they substantially match. When the terminal device 20 determines that the number of required RBs of the previous time (A) and the number of required RBs of the current time (A ′) substantially match (step S104: YES), the step It returns to the process of S101. On the other hand, when the terminal device 20 determines that the number of required RBs of the previous time (A) and the number of required RBs of the current time (A ′) do not substantially match (step S104: NO), The process proceeds to step S105.
(Step S105) The terminal device 20 substitutes the required RB (A ′) of the current time into (A), returns to the process of step S101, and rejects the request for CA connection by the processes of steps S101 and S102. Control whether or not

(Step S106) When the terminal device 20 determines that the allocated number of RBs (X1) is equal to or less than the number of RBs required for communication (A) (step S102: NO), the base station does not have enough RBs. Permit a request for a CA connection from 10-1 (see FIG. 5). When the terminal device 20 does not have enough RBs, the terminal device 20 may request the base station 10-1 to perform CA connection. Then, the process proceeds to step S107.
(Step S107) In addition to the frequency band f1 of the PCell, the terminal device 20 starts a CA connection for performing communication using the frequency band f2 of the SCell, and determines whether there is data to be received. If there is no data to be received (step S107: NO), the terminal device 20 ends the communication. On the other hand, when there is data to be received (step S107: YES), the terminal device 20 acquires the value of the RB allocated in the frequency band f1 of the PCell from the base station 10-1, and the frequency band f2 of the SCell. The value of the RB allocated in the above is acquired from the base station 10-2.

  Next, in steps S108 to S111, the terminal device 20 has RBs necessary for communication in the terminal device 20 only in one of the frequency bands f1 of the PCell and the frequency band f2 of the SCell during the CA connection. If assigned, release the CA connection.

  (Step S108) First, the terminal device 20 compares the number of RBs (X1) allocated in the frequency band f1 of the PCell with the number of RBs required for communication in the terminal device 20 (A), and the number of RBs allocated It is determined whether (X1) is larger than the number of RBs (A) required for communication. If the terminal device 20 determines that the allocated number of RBs (X1) is larger than the number of RBs required for communication (A) (step S108: YES), the process proceeds to step S109. On the other hand, when the terminal device 20 determines that the allocated number of RBs (X1) is equal to or less than the number of RBs required for communication (A) (step S108: NO), the process proceeds to step S110.

  (Step S109) The terminal device 20 can secure sufficient RBs only with the number of RBs (X1) allocated in the frequency band f1 of the PCell, and needs the number of RBs (X2) allocated in the frequency band f2 of the SCell There is no Therefore, the terminal device 20 releases the CA connection in the frequency band f2 of the SCell (see FIG. 7). Then, the process returns to the process of step S101.

  (Step S110) The terminal device 20 compares the number of RBs (X2) allocated in the frequency band f2 of SCell with the number of RBs (A) required for communication in the terminal device 20, and the number of RBs allocated (X2) It is determined whether or not is larger than the number of RBs required for communication (A). If the terminal device 20 determines that the allocated number of RBs (X2) is larger than the number of RBs required for communication (A) (step S110: YES), the process proceeds to step S111. On the other hand, when the terminal device 20 determines that the allocated number of RBs (X2) is equal to or less than the number of RBs required for communication (A) (step S110: NO), the process proceeds to step S112.

  (Step S111) The terminal device 20 can secure sufficient RBs only with the number of RBs (X2) allocated in the frequency band f2 of the SCell, and does not require the RB allocated in the frequency band f1 of the PCell. Therefore, the terminal device 20 releases the CA connection in the frequency band f1 of the PCell. At this time, since the frequency band f1 is a PCell, handover is performed from the frequency band f1 to the frequency band f2, and the frequency band f2 is switched to the PCell. Then, the process returns to the process of step S101.

  In steps S112 to S115, when almost no RB is allocated in any of the frequency band f1 of the PCell and the frequency band f2 of the SCell during the CA connection, the terminal device 20 in the frequency band Release the CA connection because the connection is wasted. Here, the criterion for releasing the CA connection is whether the allocated number of RBs (X2) or number of RBs (X1) is less than the minimum number of RBs (B) that is wasted as connected. is there. The minimum number of RBs (B) can be set arbitrarily.

  (Step S112) First, the terminal device 20 compares the number of RBs (X2) allocated in the frequency band f2 of SCell with the minimum number of RBs (B), and the number of RBs allocated (X2) is the minimum number of RBs (B) It is determined whether it is smaller. When the terminal device 20 determines that the allocated number of RBs (X2) is smaller than the minimum number of RBs (B) (step S112: YES), the process proceeds to step S113. On the other hand, when the terminal device 20 determines that the allocated number of RBs (X2) is equal to or more than the minimum number of RBs (B) (step S112: NO), the process proceeds to step S114.

  (Step S113) The terminal device 20 releases the CA connection in the SCell frequency band f2 because the number of RBs (X2) allocated in the SCell frequency band f2 is so small as to be wasted as it is connected (Figure 8). Then, the process returns to the process of step S101.

(Step S114) The terminal device 20 compares the number of RBs (X1) allocated in the frequency band f1 of the PCell with the minimum number of RBs (B), and the number of RBs allocated (X1) is the minimum number of RBs (B). ) Is determined. When the terminal device 20 determines that the allocated number of RBs (X1) is smaller than the minimum number of RBs (B) (step S114: YES), the process proceeds to step S115.
(Step S115) Since the number of RBs (X1) allocated in the frequency band f1 of the PCell is so small as to be wasted as it is connected, the terminal device 20 releases the CA connection in the frequency band f1 of the PCell. Then, the process returns to the process of step S101.

  On the other hand, when the terminal device 20 determines in step S114 that the allocated number of RBs (X1) is equal to or more than the minimum number of RBs (B) (step S114: NO), the CA connection is continued and the process of step S108 is performed. Back to.

  In addition, in order to release CA connection from SCell more than PCell as much as possible, the terminal device 20 determines about SCell in step S112 first, and determines about PCell in step S114 after that.

As described above, the terminal device 20 according to the present embodiment can establish communication connection (for example, CA connection) with the base station 10 simultaneously using a plurality of frequency bands, and the acquisition unit 221, the calculation unit 222, and , And a communication control unit 223. The acquisition unit 221 acquires, from the base station 10, information (the value of the RB, the number of RBs) indicating the size of the communication resource allocated to the communication in the frequency band used for the communication. The calculator 222 calculates the size of the communication resource required for communication in the terminal device 20. The communication control unit 223 controls how many frequency bands are simultaneously used for communication connection based on the value of the RB acquired by the acquisition unit 221 and the size of the communication resource calculated by the calculation unit 222.
Accordingly, the terminal device 20 can suppress useless communication by simultaneously using a plurality of frequency bands, and can reduce power consumption.

For example, when the communication control unit 223 determines that the total of communication resources (RBs) allocated in all frequency bands connected for communication is larger than the communication resources (RB) calculated by the calculation unit, more Even if a request for communication connection (for example, CA connection) using the frequency band simultaneously is received from the base station 10, the request is rejected.
As a result, when the terminal device 20 suffices to use the communication resource (RB) allocated in the frequency band in communication connection, the terminal device 20 does not use another frequency band at the same time to perform communication connection, and therefore, a plurality of frequencies is wasted. It is possible to suppress the use of bandwidth simultaneously and to reduce power consumption.

Further, when the communication control unit 223 determines that the total of the communication resources (RB) allocated in all the frequency bands connected for communication is insufficient for the communication resources (RB) calculated by the calculation unit 222 Output a request to the base station to perform communication connection (for example, CA connection) using more frequency bands simultaneously. For example, during communication connection using one frequency band, the communication control unit 223 determines that the communication resource (RB) allocated in one frequency band is equal to or less than the communication resource (RB) required for communication in the terminal device 20. If it is determined that it has not, then a request for communication connection (for example, CA connection) using a plurality of frequency bands is simultaneously output to the base station 10.
In this way, when the terminal device 20 is short of communication resources (RB) allocated in the frequency band in communication connection, communication connection is performed using other frequency bands at the same time, and a plurality of frequency bands is wasted. At the same time, it is possible to suppress the use of communication and reduce the power consumption.

In addition, when the communication control unit 223 determines that the allocated communication resource (RB) is insufficient due to an increase in the communication resource (RB) required during communication connection, communication using more frequency bands is performed. A request for connection (for example, CA connection) is output to the base station 10.
Thus, even if the terminal device 20 selects communication using one frequency band, for example, if communication resources (RB) are insufficient thereafter, the terminal device 20 simultaneously performs communication connection using a plurality of frequency bands. Can. In addition, when the terminal device 20 is simultaneously performing communication connection (for example, CA connection) using a plurality of frequency bands, when the communication resource (RB) runs short, more frequency bands can be simultaneously transmitted. It can also be used for communication connection.

Further, during communication connection using a plurality of frequency bands (for example, CA connection) at the same time, communication control section 223 uses the communication resource (RB) calculated by calculation section 222 only in part of the frequency bands in communication connection. If it is determined that allocation is performed, a request to release communication connection using a frequency band other than the partial frequency band is output to the base station.
Thereby, the terminal device 20 can reduce the frequency band used for communication if it is not necessary even during communication connection (for example, CA connection) using a plurality of frequency bands simultaneously. Therefore, the terminal device 20 can suppress useless communication by simultaneously using a plurality of frequency bands, and can reduce power consumption.

In addition, during communication connection (for example, CA connection) simultaneously using a plurality of frequency bands, the size of the communication resource (RB) allocated is less than a predetermined value (for example, the minimum number of RBs). When there is a frequency band in communication connection, a request to release communication connection using the frequency band is output to the base station 10.
Thus, the terminal device 20 does not use an ineffective frequency band, and therefore, it is possible to suppress wasteful communication by simultaneously using a plurality of frequency bands, and to suppress power consumption.

  In addition, when it is determined that the allocated communication resource (RB) is insufficient during communication connection (for example, CA connection) simultaneously using a plurality of frequency bands, the communication control unit 223 uses another frequency band. It outputs a request for simultaneously performing the communication connection to the base station 10. Thereby, the terminal device 20 can use three frequency bands when communication resources (RB) are insufficient in communication connection (for example, CA connection) using two frequency bands, for example. If not, four or more frequency bands can be used.

  A part of the terminal device 20 in the embodiment described above, for example, the function of the terminal control unit 220 may be realized by a computer. In that case, a program for realizing this function may be recorded in a computer readable recording medium, and the program recorded in the recording medium may be read and executed by a computer system. Here, the “computer system” is a computer system built in the terminal device 20, and includes an OS and hardware such as peripheral devices. The term "computer-readable recording medium" refers to a storage medium such as a flexible disk, a magneto-optical disk, a ROM, a portable medium such as a ROM or a CD-ROM, or a hard disk built in a computer system. Furthermore, the “computer-readable recording medium” is one that holds a program dynamically for a short time, like a communication line in the case of transmitting a program via a network such as the Internet or a communication line such as a telephone line. In such a case, a volatile memory in a computer system serving as a server or a client may be included, which holds a program for a predetermined time. The program may be for realizing a part of the functions described above, or may be realized in combination with the program already recorded in the computer system.

  As mentioned above, although one embodiment of this invention was described in detail with reference to drawings, a specific structure is not restricted to the above-mentioned thing, Various design changes etc. in the range which does not deviate from the summary of this invention It is possible to For example, although CA (carrier aggregation) in LTE-A has been described as an example in the above embodiment, the present invention is not limited thereto. For example, link aggregation (LTE, WiFi (registered trademark), different networks such as 3G Can also be applied under heterogeneous network environments (in which various networks coexist).

  DESCRIPTION OF SYMBOLS 1 mobile communication system, 10 base stations, 20 terminal devices, 110 communication units, 111 transmission units, 112 reception units, 120 control units, 201 display units, 202 operation reception units, 210 terminal communication units, 211 transmission units, 212 receptions Unit, 220 terminal control unit, 221 acquisition unit, 222 calculation unit, 223 communication control unit

Claims (6)

A terminal device capable of performing communication connection with a base station using a plurality of frequency bands simultaneously,
An acquisition unit that acquires, from a base station, information indicating the size of communication resources allocated to communication in a frequency band used for communication;
A calculation unit that calculates the size of communication resources required for communication in the own terminal device;
A communication control unit configured to control how many frequency bands are simultaneously used to perform communication connection based on the information acquired by the acquisition unit and the size of the communication resource calculated by the calculation unit;
Equipped with
The communication control unit
When it is determined that the total of communication resources allocated in all frequency bands connected for communication is larger than the communication resource calculated by the calculation unit, the communication connection request simultaneously using more frequency bands is the base station also come from to refuse terminal equipment. The communication control unit
If it is determined that the total of the communication resources allocated in all the communication-connected frequency bands is insufficient for the communication resources calculated by the calculation unit, the communication connection using more frequency bands simultaneously is performed. Output the request to the base station,
The terminal device according to claim 1 . The communication control unit
If it is determined that the communication resource calculated by the calculation unit is allocated only in a part of the frequency bands in communication connection during the communication connection using the plurality of frequency bands simultaneously, frequencies other than the part of the frequency bands Output to the base station a request to release the communication connection using the band,
The terminal device according to claim 1 or 2 . The communication control unit
During the communication connection using a plurality of frequency bands at the same time, when there is a frequency band in communication connection where the size of the allocated communication resource is less than a predetermined value, a request to release the communication connection using the frequency band is Output to the base station
The terminal device according to any one of claims 1 to 3 . A communication control method in a terminal apparatus capable of communication connection with a base station using a plurality of frequency bands simultaneously,
An acquisition process in which an acquisition unit acquires, from a base station, information indicating the size of a communication resource allocated to communication in a frequency band used for communication;
A calculation process in which the calculation unit calculates the size of communication resources required for communication in the own terminal device;
A communication control process in which a communication control unit controls how many frequency bands are simultaneously used for communication connection based on the information acquired by the acquisition unit and the size of the communication resource calculated by the calculation unit;
If it is determined that the total of the communication resources allocated in all frequency bands connected for communication is larger than the communication resource calculated in the calculation process, the communication connection request simultaneously using more frequency bands is the base station The refusal process to reject even if it comes from,
Communication control method including: A computer as a terminal device capable of communication connection with a base station using a plurality of frequency bands simultaneously;
An acquisition procedure for acquiring, from a base station, information indicating the size of a communication resource allocated to communication in a frequency band used for communication;
A calculation procedure for calculating the size of communication resources required for communication in the own terminal device;
A communication control procedure for controlling how many frequency bands are simultaneously used for communication connection based on the information acquired in the acquisition procedure and the size of the communication resource calculated in the calculation procedure;
If it is determined that the total of communication resources allocated in all frequency bands connected for communication is larger than the communication resource calculated in the calculation procedure, the communication connection request simultaneously using more frequency bands is the base station The refusal procedure to reject even if it comes from,
A program to run a program.

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