JP4928486B2 - Wireless communication method, wireless communication system, and wireless terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption in a radio terminal by reducing traffic in random access. <P>SOLUTION: A base station 30 determines the next polling timing to the radio terminal 40 for each radio terminal 40, and notifies the radio terminal 40 of the determined next polling timing. The radio terminal 40 selects one of a random access method and a polling method as a data transmission method according to the next polling timing notified by the base station 30. The radio terminal 40 stands by in a sleep state until the next polling timing, when transmitting data at the notified, next polling timing. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

The present invention relates to a radio communication method , a radio communication system, and a radio terminal between a radio base station apparatus and a plurality of radio terminal apparatuses that transmit and receive data through a radio communication connection.

  In recent years, ubiquitous networks using short-range wireless communication systems such as wireless tags, Bluetooth, and Zigbee have begun to spread in fields centering on equipment control, transportation, distribution, environmental conservation, food / agriculture, earthquake monitoring, medical welfare, etc. Yes. In the future, with the development of applications and services, the number of users using this network is expected to increase. In view of this, a wide area ubiquitous network that can provide various applications, services, and the like to a larger number of users and that can expand the service area has attracted attention.

  FIG. 14 is a block diagram showing a schematic configuration of a wide area ubiquitous network. In the figure, a wide area ubiquitous network includes a server 1 for providing various services, a communication network (wired network) 2 to which the server 1 is connected, a base station 3 connected to the communication network 2, and a wide area. A plurality of existing wireless terminals 4-1, 4-2,..., 4-N (hereinafter referred to as a wireless terminal 4 when described as a representative wireless terminal). The wireless terminals 4-1, 4-2,..., 4-N are directly accommodated in the base station 3. Although a plurality of base stations 3 are connected to the wide area ubiquitous network, only one base station 3 will be described. The wireless terminal 4 in the wide area ubiquitous network is a battery-powered terminal having a low power consumption and a low function having only minimum functions such as data measurement and measurement data transmission.

  For this reason, the traffic from the wireless terminal 4 is characterized by (1) a small amount of data, (2) a relatively long transmission interval, and (3) a high periodicity with respect to data generation. Since there are a large number of such wireless terminals 4 under the control of one base station 3, there is a lot of uplink periodic traffic as traffic characteristics, and the total traffic tends to increase. Furthermore, since the purpose of the wide-area ubiquitous network is to collect data from as many wireless terminals 4 as possible, it is necessary to efficiently accommodate as many wireless terminals 4 as possible in one base station 3. Therefore, the wide area ubiquitous network requires a MAC (Medium Access Control) protocol that can realize a high throughput and a low transmission delay time while efficiently accommodating many low-function wireless terminals 4 in one base station 3. The

  As a MAC protocol that satisfies the above requirements, a dynamic slot assignment (DSA) method, which is one of centralized control methods with high resource utilization efficiency, is known. In the dynamic slot assignment, the base station 3 dynamically assigns a band (slot) according to a request from the wireless terminal 4. FIG. 15 is a conceptual diagram illustrating an example of a MAC frame in TDMA-TDD (Time Division Multiple Access-Time Division Duplex). The MAC frame is divided into a downlink and an uplink. The downlink includes a broadcast section and a demand assignment section, and the uplink includes a demand assignment (DA) section and a random access (RA) section. The demand assignment section is a bandwidth allocation region for each wireless terminal 4 or wireless link, and is an area that can be accessed without contention. On the other hand, the random access section is an area used by a plurality of wireless terminals 4 and is a contention-based access area.

  In order to transmit / receive data, control information, etc., Bch (Broadcast control channel), RFch (Random access Feedback channel), Fch (Frame control channel), Cch (Control channel: control channel), Dch (Data channel: data channel), and Rch (Random access channel) channels are used. Bch informs the radio terminal 4 of the attributes (base station ID, etc.) of the base station 3, and Fch uses the radio terminal 4 (in the demand assignment section in which slot allocation is performed for each radio terminal 4 (or radio link). In order to notify information on band allocation for each (or radio link) (for example, ID, allocation position, allocation amount, etc. that can identify the radio terminal 4 (or radio link) to which the band is allocated), the RFch uses random access information. (Random access result of previous frame, start position of random access in this frame, number of slots, etc.). Cch is control information for each wireless terminal 4 (or wireless link) such as a bandwidth request (Resource Request: RREQ) or ARQ (Automatic Repeat Request), and Dch is used to transmit and receive user data. Rch is a channel for random access, and is used for the radio terminal 4 to transmit the RREQ.

  As the dynamic slot allocation method, there is a method in which the wireless terminal 4 uses random access to make a bandwidth request to the base station 3. The random access method is widely applied as a dynamic slot allocation method because it can flexibly and efficiently accommodate non-periodic data generated in a burst manner. FIG. 16 is a sequence diagram illustrating an example of an uplink data transmission sequence using a random access method according to the related art. In the illustrated example, the base station 3 transmits Bch, RFch, and Fch in order from the beginning of the MAC frame. By receiving the RFch, the wireless terminal 4 under the base station 3 can know the random access start position and the number of slots in the frame.

When transmitting data, the wireless terminal 4 transmits RREQ using Rch to request a band for transmission data. At this time, the wireless terminal 4 autonomously determines a back-off time that is a transmission standby time based on the Exponential back-off algorithm in order to avoid a collision with another wireless terminal. When the back-off time is completed, the wireless terminal 4 transmits the RREQ in the corresponding Rch slot. If there is a collision with Rch from another wireless terminal, it is retransmitted. When the base station 3 can correctly receive the RREQ, the base station 3 notifies the success of the RREQ reception by the RFch of the next frame, and assigns the Dch corresponding to the bandwidth request value from the RREQ. Further, in the next frame to which the Dch is assigned, an ARQ Cch for transmitting an arrival confirmation for the Dch to the wireless terminal 4 is assigned.
Development of 5 GHz band advanced wireless access (AWA) system -MAC / DCL function-, 2000, IEICE Society Conference, B-5-39, pp. 327

  However, in the dynamic slot allocation (DSA) method using random access according to the above-described prior art, many data are subordinate to the base station 3 at the time of data transmission from the wireless terminal 4, particularly at the time of RREQ transmission to the random access section. , 4-N exist and the access to the random access section is increasing, there is a high possibility that the Rch will collide and the overhead associated with the collision increases. To do. This overhead is a transmission waiting time based on the exponential back-off algorithm, and there is a problem that this deteriorates throughput characteristics. Furthermore, since the back-off operation and the transmission operation increase as the overhead increases, there is a problem that the power consumption of the wireless terminal is increased and the battery life is shortened.

The present invention has been made in consideration of such circumstances, and its object is to reduce random access traffic, improve the utilization efficiency of radio resources, and further reduce the power consumption of radio terminals. An object of the present invention is to provide a wireless communication method , a wireless communication system, and a wireless terminal capable of reducing the battery life and extending the battery life.

In order to solve the above-described problem, the present invention is configured such that a plurality of radio terminals are connected to a base station through a common radio channel, and the base station assigns an allocation band among uplink communication bands in a radio frame as a demand assignment. In addition to managing the section and the remaining bandwidth as a random access section, the wireless terminal performs polling assignment to the wireless terminal, and the wireless terminal transmits a bandwidth request signal at an arbitrary timing in the random access section according to the assigned bandwidth. Data transmission is performed by either a random access method for performing data transmission, or a polling method for transmitting data in the bandwidth allocated for polling or the bandwidth allocated by transmitting a bandwidth request signal in the bandwidth allocated for polling. In the wireless communication method to be performed, the base station performs the following in each wireless terminal: A polling timing is determined, and the next polling timing is notified to each wireless terminal in advance, and the wireless terminal uses a random access method or a polling method as a data transmission method based on the notified next polling timing. In selecting either of the above, a request transmission timing when transmitting by the random access method and a request transmission timing or data transmission timing when transmitting by the polling method, whichever is earlier A data transmission method is selected .

  The present invention is characterized in that, in the above invention, when the wireless terminal performs request transmission or data transmission at the notified next polling timing, it waits in a sleep state until the next polling timing.

  According to the present invention, in the above invention, the wireless terminal transmits the transmission data including the generation time of the data, and the base station generates the data generation frequency in each of the wireless terminals included in the transmission data. The measurement is based on time, and the next polling timing is determined based on the measurement result.

  According to the present invention, in the above invention, the wireless terminal calculates a data generation period based on a data transmission frequency in the wireless terminal, and the transmission data includes the calculated data generation period and the generation time of the transmission data. The base station is notified, and the base station determines the next polling timing based on the notified data generation cycle and the generation time of the transmission data.

  According to the present invention, in the above invention, the wireless terminal transmits the transmission data including the generation time of the data, and the base station receives the generation time of the data received from the wireless terminal and the wireless terminal from the network side. The next polling timing is determined based on the data transmission cycle or transmission timing.

In order to solve the above-described problem, the present invention is configured such that a plurality of wireless terminals are connected to a base station through a common wireless channel, and the base station assigns an allocation band among uplink communication bands in a radio frame. The demand assignment section and the remaining bandwidth are managed as a random access section, and polling assignment is performed for the wireless terminal. The wireless terminal is assigned by transmitting a bandwidth request signal at an arbitrary timing in the random access section. Data is either a random access method in which data is transmitted by a band, or a polling method in which data is transmitted in a band allocated by transmitting a band request signal in the band allocated for polling or data transmitted in the band allocated for polling. In a wireless communication system that performs transmission, the base station includes wireless terminals A polling timing notifying unit for determining a next polling timing in advance and notifying each radio terminal of the next polling timing in advance, the radio terminal as a data transmission method at the notified next polling timing; Based on this, when selecting either the random access method or the polling method, the request transmission timing when transmitting by the random access method, and the request transmission timing or data transmission timing when transmitting by the polling method And a selection means for selecting a data transmission method at an earlier timing .

In order to solve the above-described problem, the present invention is configured such that a plurality of wireless terminals are connected to a base station through a common wireless channel, and the base station assigns an allocation band among uplink communication bands in a radio frame. While managing the demand assignment section and the remaining bandwidth as a random access section, determining the next polling timing in each wireless terminal, in advance, notifying each wireless terminal of the next polling timing, the wireless terminal, Random access method in which a bandwidth request signal is transmitted at an arbitrary timing in a random access section and data is transmitted using the allocated bandwidth, or whether the bandwidth is allocated by transmitting the bandwidth request signal in the polling allocated bandwidth. According to one of the polling methods for transmitting data in the bandwidth allocated for polling A said wireless terminal in a wireless communication method for performing chromatography data transmission, as the data transmission method, on the basis of the notified next polling time, when selecting one of the random access method or polling method, the random access A method of selecting a data transmission method at an earlier timing from a transmission timing of a request when transmitting by a method and a transmission timing of a request or a data transmission timing when transmitting by the polling method, A wireless terminal.

  According to the present invention, the base station determines the next polling timing in each radio terminal, notifies the radio terminal of the next polling timing in advance, and the radio terminal uses the next polling as a data transmission method. When the notification of timing is received, the data transmission by the polling method at that timing is selected, and when the notification of the polling timing is not received, the data transmission by the random access method is selected. Therefore, by allowing the wireless terminal to select data transmission by polling, it is possible to reduce random access traffic and improve the utilization efficiency of wireless resources.

  Further, according to the present invention, the wireless terminal is earlier between the transmission timing of the request when transmitting by the random access method and the transmission timing of the request or the data transmission timing when transmitting by the polling method. Select the timing data transmission method. Therefore, it is possible to reduce random access traffic by making it possible to select data transmission by polling while improving the utilization efficiency of radio resources.

  According to the present invention, when transmitting data at the notified next polling timing, the wireless terminal stands by in a sleep state until the next polling timing. Therefore, by allowing the wireless terminal to select data transmission by polling, it is possible to reduce random access traffic, improve the utilization efficiency of wireless resources, and further reduce the power consumption of the wireless terminal. Reduction and extension of battery life can be achieved.

  Further, according to the present invention, the wireless terminal transmits the transmission data including the generation time of the data, and the base station measures the data generation frequency at each wireless terminal based on the generation time included in the transmission data. Then, the next polling timing is determined based on the measurement result. Therefore, by allowing the wireless terminal to select data transmission by polling, it is possible to reduce random access traffic and improve the utilization efficiency of wireless resources.

  According to the present invention, the wireless terminal calculates a data generation cycle based on the data transmission frequency in the wireless terminal, and transmits the calculated data generation cycle and the transmission data generation time to the base station. The base station determines the next polling timing based on the notified data generation cycle and the transmission data generation time. Therefore, by allowing the wireless terminal to select data transmission by polling, it is possible to reduce random access traffic and improve the utilization efficiency of wireless resources.

  Further, according to the present invention, the wireless terminal transmits the transmission data including the generation time of the data, and the base station transmits the data generation time received from the wireless terminal and the data transmission period in the wireless terminal from the network side. Alternatively, the next polling timing is determined based on the transmission timing. Therefore, by allowing the wireless terminal to select data transmission by polling, it is possible to reduce random access traffic and improve the utilization efficiency of wireless resources.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a wireless communication system according to an embodiment of the present invention. Note that portions corresponding to those in FIG. 14 are denoted by the same reference numerals and description thereof is omitted. In FIG. 1, the base station 30 is configured for each wireless terminal 40-1 to 40-N (hereinafter, described as a wireless terminal 40 when described as a representative wireless terminal) (or for each wireless link). A polling timing determination unit 30-1 that determines the next polling timing for the wireless terminal 40 and a polling timing notification unit 30-2 that notifies the wireless terminal 40 of the determined next polling timing are provided.

  In addition, the wireless terminal 40 includes a data transmission method selection unit 40-1-1 that selects either a random access method or a polling method. In FIG. 1, only the wireless terminal 40-1 is shown to include the data transmission method selection unit 40-1-1. However, the present invention is not limited to this, and a plurality of wireless terminals 40 or all the wireless terminals 40- 1-40-N may be provided.

  Here, the polling method and the random access method will be described. There are two types of radio access methods for uplink data transmission: the polling method and the random access method. As shown in FIG. 16 described above, the random access method is usually a method in which the radio terminal 40 selects at the time of uplink data transmission, and therefore there is no processing performed by the base station 30 for the radio terminal 40.

  The base station 30 polls the bandwidth for uplink data transmission for each wireless terminal 40. In the present embodiment, in particular, the base station 30 notifies the wireless terminal 40 of information (polling information) about the next polling for each wireless terminal 40 in advance. Here, the polling information notified in advance includes polling timing information and polling channel information. The polling timing information is information that allows the radio terminal 40 to specify a frame in which the base station 30 next allocates a bandwidth for uplink data transmission to the radio terminal 40. The polling channel information is information regarding two types of channels Cch and Dch that the base station 30 allocates to the radio terminal 40 for uplink data transmission.

  Here, FIG. 2 is a sequence diagram showing a data transmission sequence of the RREQ polling method. FIG. 3 is a sequence diagram showing a data transmission sequence of the Data polling method. In the present embodiment, the RREQ Cch shown in FIG. 2 or the Data Dch shown in FIG. 3 is allocated to the polling channel. In the case of Dch, since Dch has a variable length, the Dch length is included in the channel information.

  FIG. 4 is a flowchart for explaining the operation of the polling information notification process in the base station 30 according to the embodiment of the present invention. The polling information notification process is performed for each wireless terminal 40. First, the base station 30 calculates the polling timing for the next data for the radio terminal 40 (step Sa1). This is because (A1) a method of calculating from a measurement result in the base station 30, (A2) a method of calculating based on a polling cycle report from the wireless terminal 40, and (A3) data transmission in the wireless terminal 40 from the network side There is a method of calculating from a notification of a cycle or transmission timing.

As a specific method,
In the case of (A1), the wireless terminal 40 transmits the transmission data including the generation time of the data, and the base station 30 starts from the generation time included in the plurality of transmission data transmitted from each wireless terminal 40. , Calculate the occurrence interval from the previous and next occurrence time, calculate the occurrence cycle from the occurrence interval (identify the average of the occurrence intervals as the occurrence cycle, identify the longest occurrence interval as the occurrence cycle), and finally received The next data generation time (polling timing) is determined by adding the data generation cycle calculated to the transmission data generation time.
In the case of (A2), the wireless terminal 40 calculates a polling period (data generation period) based on the data transmission frequency (data transmission period) in the wireless terminal 40, and the calculated polling period for the transmission data. And the generation time of the transmission data are notified to the base station 30, and the base station 30 sets the wireless terminal 40 at the generation time of the last received transmission data based on the notified data generation cycle and the generation time of the transmission data. The next data generation time (polling timing) is determined by adding the calculated data generation cycle.
In the case of (A3), the wireless terminal 40 transmits the transmission data including the generation time of the data, and the base station 30 transmits the generation time of the data received last from the wireless terminal 40 and the network side. The next data generation time (polling timing) is determined by adding the data generation cycle in the wireless terminal 40.

  Next, in the polling information notification process, a polling information generation process for creating polling information and determining the polling information notification timing is executed (step Sa2). As described above, the polling information includes polling timing information and polling channel information. The polling timing information includes (B1) the frame number itself, (B2) an offset value from the reference frame (the polling information notification frame), and (B3) a flag indicating the presence / absence of polling. The polling channel information includes the above-described RREQ Cch, Data Dch, and Dch length. Also, the notification timing of polling information includes (C1) a timing at which notification is possible immediately after the creation of polling information, and (C2) a specific frame.

  Next, the polling information is notified to the wireless terminal 40 at the polling information notification timing determined in the same process (step Sa3). At this time, as a notification method, there are a method of (D1) transmitting for each wireless terminal 40 and (D2) transmitting on a broadcast channel. In the MAC frame configuration shown in FIG. 15, transmission is performed using Cch / Dch in the downlink demand assignment (DA) section in the case of (D1) and using Bch in the case of (D2).

  5 and 6 are conceptual diagrams illustrating examples of polling information notification according to the present embodiment. In the present embodiment, the base station 30 receives data from the wireless terminal 40 in the frame F0, and sets the next data polling timing as the frame F7. In FIG. 5, the notification timing of polling information is the frame F1 immediately after reception described in (C1) above, and the polling timing information is the frame F7 in (B1) above or the offset (6) described in (B2) above. Is informed. The polling information is transmitted using the Bch described in (D2) above. In FIG. 6, the polling information notification timing is the frame before the polling described in (C2), and the flag (ON) described in (B3) is notified as polling timing information. This is different from FIG. The polling information is transmitted using the Bch described in (D2) as in FIG. In FIGS. 5 and 6, although the frames are continuous, this may be a wake-up frame when the wireless terminal 40 sleeps.

  Next, an embodiment in which prior notification of polling information at the base station is applied to wireless terminals with different wireless access methods will be described.

[First embodiment]
In the first embodiment, the radio terminal 40 preferentially uses a polling method for uplink data transmission. When receiving the prior notification of the polling information from the base station 30 as described above, the wireless terminal 40 applies the polling method to the next data transmission. In the first embodiment, in order to prioritize the polling method, the wireless terminal 40 performs the wireless access control process of FIGS.

  FIG. 7 is a flowchart for explaining an operation performed by the wireless terminal 40 when receiving a polling information notification from the base station 30 in the first embodiment. The radio terminal 40 determines whether or not a random access (RA) method is set (step Sb1), and if set (YES in step Sb1), executes a random access (RA) stop process. Then, the back-off control is stopped (step Sb2). Next, polling setting processing is executed, and based on the received polling information, a polling frame is acquired from the notified polling timing information, and a polling channel is acquired from the polling channel information (step Sb3).

  Next, FIG. 8 is a flowchart for explaining the operation that the wireless terminal 40 executes at the start of data transmission in the first embodiment. Here, the data transmission start means data transmission start accompanying data generation and buffering data transmission start accompanying data transmission completion. The wireless terminal 40 determines whether or not the polling setting process described with reference to FIG. 7 is performed (step Sc1), and if it is not set (NO in step Sc1), the random access (RA) method is set. As a process, back-off control is started (step Sc2). When data transmission by the random access (RA) method is completed, the selection of the random access (RA) method is cancelled.

  Next, FIG. 9 is a flowchart for explaining an operation performed by the radio terminal 40 during polling by the base station 30 in the first embodiment. The radio terminal 40 determines whether or not there is transmission data (step Sd1). If there is transmission data (YES in step Sd1), the RREQ Cch is polled, as shown in FIG. When the sequence and Dch for Data are polled, data is transmitted according to the sequence shown in FIG. 3 (step Sd2), and after the transmission is completed, the polling setting process is canceled (step Sd3). On the other hand, if there is no transmission data (NO in step Sd1), the polling setting process is canceled in step Sd3, and the process ends.

  In the first embodiment described above, since transmission by polling is prioritized, it is possible to enter a sleep state until the next polling frame after receiving the polling information notification. This can be realized by periodically providing a wake-up (Wake Up) frame that is activated and received from the sleep state, and matching the polling timing with the wake-up timing (usually, the base station 30 is a wireless terminal having a sleep function) 40, when downlink data is transmitted, a wakeup frame is periodically provided, and downlink transmission is performed in the wakeup frame). Thereby, even if transmission data occurs during sleep, it is not necessary to perform transmission by the random access method, and it is not necessary to start processing of the random access method, and it is possible to continue the sleep state. Power consumption can be reduced.

[Second Embodiment]
In the second embodiment, the radio terminal 40 selects one of the random access method and the polling method for uplink data transmission that has an earlier access start time (that is, one that has a earlier timing until a request is transmitted). In the second embodiment, the radio terminal 40 performs the radio access control process of FIGS. 10 to 13 in order to select a radio access method.

  FIG. 10 is a flowchart for explaining an operation performed by the wireless terminal 40 when receiving a polling information notification from the base station 30 in the second embodiment. Here, as in step Sb3 of FIG. 7 described in the first embodiment, the polling frame is acquired from the notified polling timing information and the polling channel is acquired from the polling channel information based on the received polling information. The polling setting process is executed (step Se1).

  Next, FIG. 11 is a flowchart for explaining an operation executed by the wireless terminal 40 at the start of data transmission in the second embodiment. Here, as in step Sc2 of FIG. 8 described in the first embodiment described above, back-off control is activated as setting processing for the random access (RA) method (step Sf1).

  Next, FIG. 12 is a flowchart for explaining an operation executed by the radio terminal 40 during polling by the base station 30 in the second embodiment. This process is substantially the same as that of FIG. 9 described in the first embodiment, but differs in that a random access (RA) stop process is executed after executing a transmission process by polling. That is, the wireless terminal 40 determines whether or not there is transmission data (step Sg1). If there is transmission data (YES in step Sg1), the RREQ Cch is polled. When the data Dch is polled, data is transmitted according to the sequence shown in FIG. 3 (step Sg2), and after the transmission is completed, a random access (RA) stop process is executed and backoff is performed. Control is stopped (step Sg3), and then the polling setting process is canceled (step Sg4). On the other hand, if there is no transmission data (NO in step Sg1), the polling setting process is canceled in step Sg4, and the process ends.

  Next, FIG. 13 is a flowchart for explaining an operation performed by the wireless terminal 40 when the back-off is completed in the second embodiment. When the back-off is completed, the wireless terminal 40 performs RREQ transmission by a random access (RA) method (step Sh1). When the transmission is completed, the random access (RA) setting is canceled (step Sh2). Next, it is determined whether or not the polling has been set (step Sh3). If polling has been set upon completion of transmission by the random access (RA) method (YES in step Sh3), the polling setting is changed. Release (step Sh4).

  In the second embodiment described above, the radio terminal 40 selects the one with the earlier access start time (that is, the one with the earlier time until the request is transmitted). When the RREQ is received from the wireless terminal 40 by the random access (RA) method, the polling is canceled.

  According to the above-described embodiment, the base station 30 notifies polling information to the radio terminal 40 in advance, and allows the radio terminal 40 to select data transmission by polling, thereby reducing random access traffic. can do. Thereby, the utilization efficiency of the radio | wireless resource by polling can be improved, and the low power consumption by the polling utilization which is lower power consumption than random access is realizable.

It is a block diagram which shows the structure of the radio | wireless communications system by embodiment of this invention. It is a sequence diagram which shows the data transmission sequence of a RREQ polling method. It is a sequence diagram which shows the data transmission sequence of a Data polling method. It is a flowchart for demonstrating operation | movement of the polling information notification process in the base station 30 by embodiment of this invention. It is a conceptual diagram which shows the polling information notification example by this embodiment. It is a conceptual diagram which shows the polling information notification example by this embodiment. 5 is a flowchart for explaining an operation that is performed when the wireless terminal 40 receives a polling information notification from the base station 30 in the first embodiment. 5 is a flowchart for explaining an operation performed by the wireless terminal 40 at the start of data transmission in the first embodiment. 5 is a flowchart for explaining an operation performed by the radio terminal 40 during polling by the base station 30 in the first embodiment. FIG. 10 is a flowchart for explaining an operation performed by the wireless terminal 40 when receiving a polling information notification from the base station 30 in the second embodiment. In 2nd Example, it is a flowchart for demonstrating the operation | movement which the radio | wireless terminal 40 performs at the time of a data transmission start. In 2nd Example, it is a flowchart for demonstrating the operation | movement which the radio | wireless terminal 40 performs at the time of the polling by the base station 30. FIG. In 2nd Example, it is a flowchart for demonstrating the operation | movement which the radio | wireless terminal 40 performs when back-off completion. It is a block diagram which shows the schematic structure of a wide area ubiquitous network. It is a conceptual diagram which shows an example of the MAC frame in TDMA-TDD. It is a sequence diagram which shows an example of the data transmission sequence of the uplink using a random access method by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Server 2 Wired network 30 Base station 30-1 Polling timing determination part 30-2 Polling timing notification part 40-1 to 40-N Wireless terminal 40-1-1 Data transmission method selection part

Claims (7)

A plurality of radio terminals are connected to a base station through a common radio channel, and the base station manages an allocation band among uplink communication bands in a radio frame as a demand assignment section and the remaining bands as a random access section. Performing a polling assignment to a wireless terminal, wherein the wireless terminal transmits a bandwidth request signal at an arbitrary timing in the random access section and performs data transmission using the assigned band, or the polling assignment. In a wireless communication method for performing data transmission by either a bandwidth allocated by transmitting a bandwidth request signal in a band to be transmitted or a polling method for transmitting data in a bandwidth allocated for polling,
The base station determines the next polling timing in each wireless terminal, and notifies the wireless terminal of the next polling timing in advance,
When the wireless terminal selects either the random access method or the polling method based on the notified next polling timing as the data transmission method ,
The transmission timing of the request when transmitting by the random access method;
Request transmission timing or data transmission timing when transmitting by the polling method,
A wireless communication method , wherein a data transmission method at an earlier timing is selected . The wireless terminal is
The wireless communication method according to claim 1, wherein when request transmission or data transmission is performed at the notified next polling timing, the wireless communication method waits in a sleep state until the next polling timing. The wireless terminal is
Send the transmission data including the time of occurrence of the data,
The base station
2. The wireless communication according to claim 1, wherein the frequency of data generation at each wireless terminal is measured based on the time of occurrence included in the transmission data, and the next polling timing is determined based on the measurement result. Method. The wireless terminal is
Calculate a data generation period based on the data transmission frequency in the wireless terminal, and notify the base station of the calculated data generation period and the generation time of the transmission data to transmission data,
The base station
The wireless communication method according to claim 1, wherein a next polling timing is determined based on the notified data generation cycle and the generation time of the transmission data. The wireless terminal is
Send the transmission data including the time of occurrence of the data,
The base station determines a next polling timing based on a generation time of data received from a wireless terminal and a data transmission cycle or transmission timing in the wireless terminal from the network side. Wireless communication method. A plurality of radio terminals are connected to a base station through a common radio channel, and the base station manages an allocation band among uplink communication bands in a radio frame as a demand assignment section and the remaining bands as a random access section. Performing a polling assignment to a wireless terminal, wherein the wireless terminal transmits a bandwidth request signal at an arbitrary timing in the random access section and performs data transmission using the assigned band, or the polling assignment. In a wireless communication system for performing data transmission by either a band allocated by transmitting a band request signal in a band to be transmitted or a polling method for transmitting data in a band allocated for polling,
The base station includes a polling timing notifying unit that determines a next polling timing in each wireless terminal and notifies the wireless terminal of the next polling timing in advance.
When the wireless terminal selects either the random access method or the polling method based on the notified next polling timing as the data transmission method, the transmission timing of the request when transmitting by the random access method And a selection means for selecting a data transmission method at an earlier timing from a transmission timing of a request or a data transmission timing when transmitting by the polling method ,
A wireless communication system. A plurality of radio terminals are connected to a base station through a common radio channel, and the base station manages an allocation band among uplink communication bands in a radio frame as a demand assignment section and the remaining bands as a random access section. The next polling timing in each wireless terminal is determined, the next polling timing is notified to each wireless terminal in advance, and the wireless terminal transmits a bandwidth request signal at an arbitrary timing in the random access section. Either a random access method for transmitting data in the allocated band, or a polling method for transmitting data in the polled band or the band allocated by transmitting a band request signal in the polled band The wireless terminal in a wireless communication method for transmitting data by There is,
In selecting either a random access method or a polling method based on the notified next polling timing as a data transmission method ,
The transmission timing of the request when transmitting by the random access method;
Request transmission timing or data transmission timing when transmitting by the polling method,
A wireless terminal that selects a data transmission method at an earlier timing .

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