Wireless communication system and wireless communication method

Abstract

Provided is a wireless communication system comprising a plurality of wireless communication devices and a base station device. An allocation wireless communication device, which is one of the plurality of wireless communication devices, is provided with an allocation unit for allocating traffic to one or more wireless communication devices that are candidate wireless communication devices to be caused to perform cooperative operation and that are not connected with the base station device. The one or more wireless communication devices are provided with: a wireless state information acquisition unit that acquires wireless state information, which is information pertaining to the quality of wireless communication, by performing wireless communication with the base station device in accordance with the traffic allocated by the allocation wireless communication device; and a communication unit that transmits the wireless state information acquired by the wireless state information acquisition unit to the allocation wireless communication device.　

Description

Wireless communication system and wireless communication method

[0001] The present invention relates to a wireless communication system and a wireless communication method.

[0002] In recent years, the use of millimeter waves has been widely studied to increase the speed and capacity of wireless communications. However, millimeter waves have a high degree of directivity and are subject to significant attenuation due to factors such as moisture in the atmosphere. Therefore, compared to lower frequency bands such as Sub-6 (less than 6 GHz), degradation in quality due to self-shielding by structures and human bodies, fading, or imperfect beam tracking caused by terminal rotation, etc., is a serious issue. To address this issue, terminal cooperation techniques have been proposed that improve millimeter wave communication stability by cooperative operation among multiple terminal groups (see, for example, Non-Patent Documents 1 and 2). Cooperation among terminal groups located in close proximity can ensure path diversity among multiple terminals, thereby improving millimeter wave stability.

[0003] H. Murata, “Terminal selection schemes in terminal-collaborated MIMO reception based on subband channel matrices,” IEEE communications letters, vol.26, no.1, Jan. 2022.K. Yamazaki, et.al., “Proposal for a user-centric RAN architecture towards beyond 5G,”in Proc. Of 2021 ITU Kaleidoscope: Connecting physical and virtual worlds, 2021.

[0004] The selection of cooperative terminals is performed based on information acquired by each candidate terminal. However, terminals that are candidates for cooperative terminals are not always connected to a base station device. In this case, a terminal for which information is not available may be excluded from the candidates for cooperative terminal selection. Therefore, a technology is desired that allows each terminal to efficiently acquire information used for selecting cooperative terminals.

[0005] In view of the above circumstances, an object of the present invention is to provide a technique that enables each terminal that is a candidate for cooperative terminal to efficiently acquire information used for selecting a cooperative terminal.

[0006] One aspect of the present invention is a wireless communication system comprising a plurality of wireless communication devices and a base station device, wherein an allocating wireless communication device, which is one of the plurality of wireless communication devices, is one or more wireless communication devices that are candidates for performing cooperative operation and comprises an allocation unit that allocates traffic to one or more wireless communication devices that are not connected to the base station device, and the one or more wireless communication devices are each provided with a wireless state information acquisition unit that acquires wireless state information, which is information regarding the quality of wireless communication, by performing wireless communication with the base station device in accordance with the traffic allocated by the allocating wireless communication device, and a communication unit that transmits the wireless state information acquired by the wireless state information acquisition unit to the allocating wireless communication device.

[0007] One aspect of the present invention is a wireless communication method performed by a wireless communication system having a plurality of wireless communication devices and a base station device, in which an allocating wireless communication device, which is one of the plurality of wireless communication devices, allocates traffic to one or more wireless communication devices that are candidates for performing cooperative operation and are not connected to the base station device, and the one or more wireless communication devices acquire wireless status information, which is information regarding the quality of wireless communication, by performing wireless communication with the base station device in accordance with the traffic allocated by the allocating wireless communication device, and transmits the acquired wireless status information to the allocating wireless communication device.

[0008] According to the present invention, it is possible to allow each terminal that is a candidate for a cooperative terminal to efficiently acquire information used for selecting a cooperative terminal.

[0009] FIG. 1 is a diagram showing an example of the configuration of a wireless communication system in a first embodiment. FIG. 2 is a diagram showing an example of the configuration of a terminal device in the first embodiment. FIG. 3 is a sequence diagram showing a processing flow (part 1) of a wireless communication system in the first embodiment. FIG. 4 is a sequence diagram showing a processing flow (part 2) of a wireless communication system in the first embodiment. FIG. 5 is a sequence diagram showing a processing flow (part 3) of a wireless communication system in the first embodiment. FIG. 6 is a diagram showing an example of the configuration of a wireless communication system in a second embodiment. FIG. 7 is a diagram showing an example of the configuration of a server in the second embodiment. FIG. 8 is a diagram showing an example of the configuration of a terminal device in the second embodiment.

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (First embodiment) Fig. 1 is a diagram showing an example of the configuration of a wireless communication system 100 according to the first embodiment. The wireless communication system 100 includes a base station device 10 and a plurality of terminal devices 20. Note that the number of terminal devices 20 may be any number as long as it is plural. Fig. 1 shows an example in which the wireless communication system 100 includes three terminal devices 20.

[0012] The base station device 10 is a base station device in a RAN (Radio Access Network). The base station device 10 communicates with a plurality of terminal devices 20. For example, in response to connection requests transmitted from the plurality of terminal devices 20, the base station device 10 transmits a reference signal to the terminal device 20 that is the source of the connection request. The connection request is a signal for requesting connection with the base station device 10. The reference signal is, for example, a sounding signal.

[0013] Furthermore, the base station device 10 communicates within the RAN with a terminal device 20 (hereinafter referred to as a "transmitting terminal") that wishes to transmit desired data to the base station device 10 from among the multiple terminal devices 20, and a cooperative terminal. A cooperative terminal is a terminal device 20 that performs cooperative operation, and transmits to the base station device 10 some of the data that the transmitting terminal wishes to transmit (hereinafter referred to as "data to be transmitted"). Cooperative operation is an operation in which multiple nearby terminal devices 20 cooperate with each other to achieve highly reliable communication with the base station device 10. A cooperative terminal is selected from among the multiple terminal devices 20 that belong to the same group as the transmitting terminal.

[0014] The base station device 10 transmits a downlink signal directly or via one or more terminal devices 20 to the terminal device 20 that has made a reception request, among the multiple terminal devices 20 .

[0015] The terminal device 20 is a terminal that communicates in a frequency band of millimeter waves or higher. The terminal device 20 is a terminal that is powered by power supplied from a battery that the terminal device itself has. The terminal device 20 forms a group with one or more other terminal devices 20. The terminal devices 20 that belong to each group form wireless or wired PAN (Personal Area Network) links between the terminal devices 20 that belong to the same group, thereby forming a PAN network.

[0016] A PAN is a network made up of terminals located in close proximity, and is a network that uses less power than a RAN. Figure 1 shows an example in which there is one group G1 in a wireless communication system 100, and three terminal devices 20-1 to 20-3 exist in the group G1. Note that although Figure 1 shows one group, there may be multiple groups in the wireless communication system 100.

[0017] The terminal device 20 performs cooperative operation with other terminal devices 20. When performing cooperative operation, the terminal device 20 determines a cooperative terminal from among the terminal devices 20 belonging to the same group. A method for determining a cooperative terminal will be described later. The terminal device 20 is one aspect of a wireless communication device.

[0018] The selection of a cooperative terminal is performed based on information obtained by a terminal device 20 (hereinafter referred to as a "candidate terminal") that is a candidate for the cooperative terminal. The information obtained by the candidate terminal is, for example, radio state information and terminal state information. The radio state information is information about the quality of radio communication, such as a channel quality indicator (CQI), a signal to interference noise ratio (SINR), throughput, a communication success rate, received power (e.g., a received signal strength indicator (RSSI) or a reference signal received power (RSRP)), physical layer information, etc. The terminal state information is information about the state of the terminal device 20, such as location information, acceleration information, magnetic sensor information, or remaining battery capacity.

[0019] However, as described above, not all terminal devices 20 are connected to the base station device 10. Therefore, the terminal device 20 that is the source of traffic (hereinafter referred to as the "source terminal") allocates part of the traffic to each candidate terminal that is not connected to the base station device 10 in turn, thereby generating traffic at each candidate terminal.

[0020] Here, the source terminal has a function of generating traffic to cause each candidate terminal to communicate with the base station device 10. Note that at least one of the multiple terminal devices 20 needs to be the source terminal, and the other terminal devices 20 do not need to have the function of generating traffic. Here, the traffic generated by the source terminal does not need to be data that the transmitting terminal wants to transmit. Therefore, the transmitting terminal does not necessarily have to be the source terminal, but the following explanation will be given taking the case where the transmitting terminal is the source terminal as an example.

[0021] Next, a method of allocating traffic volume for allowing each candidate terminal to perform communication with the base station device 10 in the first embodiment will be described.

[0022] [Traffic Volume Allocation Method 1] Traffic volume allocation method 1 is a method for periodically and randomly allocating part of traffic to a candidate terminal that is not connected to the base station device 10, thereby establishing a connection between the candidate terminal and the base station device 10 and acquiring radio state information. Here, (Operation 1) to (Operation 5) are shown and explained.

[0023] (Operation 1) The source terminal is set to terminal device 20-1, and terminal devices 20-2 and 20-3 are set to candidate terminals. (Operation 2) The terminal device 20-1 randomly selects a cooperative terminal from among the terminal devices 20-2 and 20-3. Here, it is assumed that the terminal device 20-2 is selected. As a result, the terminal devices 20-1 and 20-2 are connected to the base station device 10, and the terminal device 20-3 is not connected to the base station device 10.

[0024] (Operation 3) The terminal device 20-1 allocates a portion of its traffic to a candidate terminal (for example, terminal device 20-3) that is not connected to the base station device 10 at regular intervals. This generates traffic from the terminal device 20-3. If there are multiple candidate terminals, the terminal device 20-1 can allocate a portion of its traffic to the other candidate terminals in turn at regular intervals, thereby generating traffic from each candidate terminal. (Operation 4) The base station device 10 measures radio state information of candidate terminals (including the source terminal) that are connected to the base station device 10, and notifies the terminal device 20-1 of information indicating the measured radio state information. (Operation 5) The terminal device 20-1 determines a new cooperative terminal based on the radio state information of each candidate terminal obtained from the base station device 10.

[0025] [Traffic Volume Allocation Method 2] Traffic volume allocation method 2 is a method for, when a quality degradation occurs in a terminal device 20 already operating as a cooperative terminal, allocating traffic to a candidate terminal that is not in a connected state with the base station device 10, thereby connecting the candidate terminal and the base station device 10 and acquiring radio state information. Here, (Operation 1) to (Operation 6) are shown and explained.

[0026] (Operation 1) The source terminal is set to terminal device 20-1, and terminal devices 20-2 and 20-3 are set to candidate terminals. (Operation 2) The terminal device 20-1 randomly selects a cooperative terminal from among the terminal devices 20-2 and 20-3. Here, it is assumed that the terminal device 20-2 is selected. As a result, the terminal devices 20-1 and 20-2 are connected to the base station device 10, and the terminal device 20-3 is not connected to the base station device 10.

[0027] (Operation 3) The base station device 10 measures radio state information of a candidate terminal (e.g., terminal device 20-2) in a connected state. The base station device 10 notifies the terminal device 20-1 of the measured radio state information. (Operation 4) If the terminal device 20-1 determines that the quality degradation condition is satisfied based on the radio state information of the terminal device 20-2, it allocates a portion of its traffic to a candidate terminal (e.g., terminal device 20-3) that is not in a connected state with the base station device 10. This causes traffic to be generated from the terminal device 20-3. Note that if there are multiple candidate terminals, the terminal device 20-1 may allocate a portion of its traffic to the other candidate terminals in turn at regular intervals, thereby generating traffic from each candidate terminal. The quality degradation condition is a condition indicating that the radio quality indicated by the radio state information has deteriorated, such as the received power being below a threshold or the channel quality index being below a threshold.

[0028] (Operation 5) The base station device 10 measures the radio state information of the newly connected candidate terminal (for example, terminal device 20-3) and notifies the terminal device 20-1 of the measured radio state information. (Operation 6) The terminal device 20-1 determines a new cooperative terminal based on the radio state information of each candidate terminal obtained from the base station device 10.

[0029] [Traffic Volume Allocation Method 3] Traffic volume allocation method 3 is a method for allocating traffic to a candidate terminal that is not connected to the base station device 10 when the installation state of a cooperative terminal that is already operating as a cooperative terminal changes, thereby connecting the candidate terminal and the base station device 10 and acquiring radio state information. This is intended to detect connection instability of a terminal device 20 that is already being used as a cooperative terminal from physical information. Here, (Operation 1) to (Operation 7) are shown and explained.

[0030] (Operation 1) The source terminal is set to terminal device 20-1, and terminal devices 20-2 and 20-3 are set to candidate terminals. (Operation 2) The terminal device 20-1 randomly selects a cooperative terminal from among the terminal devices 20-2 and 20-3. Here, it is assumed that the terminal device 20-2 is selected. As a result, the terminal devices 20-1 and 20-2 are connected to the base station device 10, and the terminal device 20-3 is not connected to the base station device 10.

[0031] (Operation 3) The terminal device 20-2 measures terminal state information and notifies the terminal device 20-1 of the measured terminal state information. (Operation 4) The terminal device 20-1 determines whether the installation state of the terminal device 20 connected to the base station device 10 has changed based on the terminal state information notified from the terminal device 20 (for example, the terminal device 20-2) that is connected to the base station device 10. For example, if the amount of change in acceleration exceeds a threshold, the terminal device 20-1 determines that the installation state of the terminal device 20-2 has changed. Note that although the determination based on acceleration is shown as an example here, the determination may also be based on location information.

[0032] (Operation 5) When the terminal device 20-1 determines that the installation state of the terminal device 20 connected to the base station device 10 has changed, it allocates part of its traffic to a candidate terminal (for example, the terminal device 20-3) that is not connected to the base station device 10. This causes traffic to be generated from the terminal device 20-3. Note that if there are multiple candidate terminals, the terminal device 20-1 may allocate part of its traffic to the other candidate terminals in turn at regular time intervals, thereby generating traffic from each candidate terminal.

[0033] (Operation 6) The base station device 10 measures the radio state information of the newly connected candidate terminal (for example, the terminal device 20-3) and notifies the terminal device 20-1 of the measured radio state information. (Operation 7) The terminal device 20-1 determines a new cooperative terminal based on the radio state information obtained from the base station device 10.

[0034] 2 is a diagram showing an example of the configuration of the terminal device 20 according to the first embodiment. The terminal device 20 includes a RAN communication unit 21, a PAN communication unit 22, a reception processing unit 23, a control unit 24, and a group terminal information storage unit 25.

[0035] The RAN communication unit 21 is a wireless interface for the RAN. The RAN communication unit 21 communicates with the base station device 10. For example, the RAN communication unit 21 transmits a connection request to the base station device 10 and receives a reference signal transmitted from the base station device 10.

[0036] The PAN communication unit 22 is a wireless interface for the PAN. The PAN communication unit 22 communicates with the terminal devices 20 in the group. The PAN communication unit 22 transmits, for example, terminal status information to the terminal devices 20 in the group. The PAN communication unit 22 also receives, for example, terminal status information transmitted from other terminal devices 20.

[0037] The reception processing unit 23 demodulates the received signal by performing digital signal processing on the signal received by the RAN communication unit 21 or the PAN communication unit 22 .

[0038] The control unit 24 controls the entire terminal device 20. The control unit 24 is configured using one or more processors such as a CPU (Central Processing Unit) and one or more memories. The control unit 24 realizes the functions of an operation control unit 240, a radio state information acquisition unit 241, a terminal information acquisition unit 242, an allocation control unit 243, an allocation unit 244, a cooperative terminal determination unit 245, and a communication control unit 246 by the one or more processors executing programs.

[0039] As described above, since it is sufficient for some of the terminal devices 20 to have the function of allocating traffic, some of the terminal devices 20 may not have the functions of the allocation control unit 243 and the allocation unit 244.

[0040] The operation control unit 240 sets the operation mode of its own device. Specifically, the operation control unit 240 sets the operation mode of its own device to operate in either a transmitting terminal mode or a cooperative operation mode. The transmitting terminal mode is a mode for operating as a transmitting terminal. The cooperative operation mode is a mode for performing cooperative operation with other terminal devices 20. For example, when data to be transmitted is generated, the operation control unit 240 sets the operation mode of its own device to the transmitting terminal mode. For example, when the operation control unit 240 receives an instruction from another terminal device 20 to function as a cooperative terminal, the operation control unit 240 sets the operation mode of its own device to the cooperative operation mode.

[0041] The radio state information acquisition unit 241 acquires radio state information based on an electrical signal obtained by wireless communication with the base station device 10. The radio state information acquisition unit 241 acquires the radio state information using, for example, a reference signal (e.g., a sounding signal) transmitted from the base station device 10 in response to a connection request.

[0042] The terminal information acquisition unit 242 acquires terminal state information. The terminal information acquisition unit 242 acquires location information, for example, by a Global Positioning System (GPS). Note that the terminal information acquisition unit 242 may acquire location information by any method as long as it can acquire location information of its own device.

[0043] The allocation control unit 243 determines candidate terminals to which traffic will be allocated and the amount of traffic to be allocated to the candidate terminals. Furthermore, the allocation control unit 243 determines cooperative terminals to which transmission data will be allocated and the amount of traffic (hereinafter referred to as "allocated data amount") to be allocated to each cooperative terminal. The allocation control unit 243 may determine the cooperative terminal determined by the cooperative terminal determination unit 245 as the cooperative terminal to which data will be allocated. Furthermore, the allocation control unit 243 determines the amount of traffic to be allocated (allocated data amount) in accordance with terminal status information or radio status information obtained from the cooperative terminal. For example, the allocation control unit 243 may determine the traffic amount in accordance with the performance of the cooperative terminal (e.g., remaining battery power, etc.) by referring to terminal status information obtained from the cooperative terminal, or may determine the traffic amount in accordance with the radio environment of the cooperative terminal (e.g., received power, etc.) by referring to radio status information obtained from the cooperative terminal.

[0044] The allocation unit 244 allocates the determined traffic volume to the candidate terminals to which the traffic has been allocated, as determined by the allocation control unit 243 .

[0045] When the own device operates in the transmitting terminal mode, the cooperative terminal determiner 245 determines a cooperative terminal from among the terminal devices 20 in the group. For example, based on radio state information obtained from the base station device 10, the cooperative terminal determiner 245 determines one or more terminal devices 20 whose received power is equal to or greater than a threshold as cooperative terminals.

[0046] Note that the cooperative terminal determiner 245 may use other methods to determine cooperative terminals. For example, the cooperative terminal determiner 245 may determine cooperative terminals based on location information obtained from each candidate terminal. In this case, the cooperative terminal determiner 245 determines, as cooperative terminals, one or more terminal devices 20 whose distance from the transmitting terminal is equal to or less than a threshold, based on the location information obtained from each candidate terminal.

[0047] The communication control unit 246 controls communication between the RAN communication unit 21 and the PAN communication unit 22. For example, when the own device operates in a transmitting terminal mode, the communication control unit 246 controls the PAN communication unit 22 to transmit a predetermined notification to the other terminal device 20. For example, when the own device operates in a cooperative operation mode, the communication control unit 246 may control the PAN communication unit 22 to transmit terminal status information and radio status information to the transmitting terminal.

[0048] The communication control unit 246 controls the RAN communication unit 21 to transmit traffic allocated from other terminal devices 20 to the base station device 10 .

[0049] The group terminal information storage unit 25 stores information indicating each terminal device 20 belonging to the same group, terminal status information and wireless status information of each terminal device 20. The group terminal information storage unit 25 is configured using a storage device such as a magnetic storage device or a semiconductor storage device.

[0050] (Operation example 1 in the first embodiment) Figure 3 is a sequence diagram showing the processing flow (part 1) of the wireless communication system 100 in the first embodiment. Note that the explanation of Figure 3 will be given using three terminal devices 20 as an example. Note that in explaining Figure 3, branch numbers will be added to distinguish the functional units of each terminal device 20. For example, the functional unit provided in terminal device 20-1 will be explained with "-1" added. Here, it is assumed that terminal device 20-1 is in a connected state with base station device 10, and terminal devices 20-2 and 20-3 are not in a connected state with base station device 10. Figure 3 is a diagram related to the above-mentioned [Traffic volume allocation method 1].

[0051] The allocation control unit 243-1 of the terminal device 20-1 randomly determines the destination of traffic allocation from among the terminal devices 20-2 and 20-3. For example, the allocation control unit 243-1 determines the terminal device 20-2 as the destination of traffic allocation. The allocation control unit 243-1 determines the amount of traffic to allocate to the determined terminal device 20-2. The allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the determined destination of traffic allocation and information indicating the amount of traffic to be allocated.

[0052] For example, the allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the terminal device 20-2 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20-2. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 244-1 allocates the traffic volume indicated by the traffic volume information to the terminal device 20-2 (step S101).

[0053] Specifically, the allocation unit 244-1 transmits traffic to the terminal device 20-2 via the PAN communication unit 22-1. The PAN communication unit 22-2 of the terminal device 20-2 receives the traffic transmitted from the terminal device 20-1. In response to receiving the traffic, the communication control unit 246-2 of the terminal device 20-2 controls the RAN communication unit 21-2 to transmit a connection request to the base station device 10. The RAN communication unit 21-2 of the terminal device 20-2 transmits the connection request to the base station device 10 under the control of the communication control unit 246-2 (step S102).

[0054] The base station device 10 receives a connection request transmitted from the terminal device 20-2. The base station device 10 transmits a reference signal to the terminal device 20-2 in response to the received connection request (step S103). This establishes a connection between the terminal device 20-2 and the base station device 10. The base station device 10 acquires radio state information of the terminal device 20-2 based on the connection request transmitted from the terminal device 20-2 (step S104). The base station device 10 transmits the acquired radio state information of the terminal device 20-2 to the terminal device 20-1 (step S105).

[0055] The RAN communication unit 21-1 of the terminal device 20-1 receives the radio state information of the terminal device 20-2 transmitted from the base station device 10. The communication control unit 246-1 stores the received radio state information of the terminal device 20-2 in the group terminal information storage unit 25.

[0056] Next, after a certain period of time has elapsed, the allocation control unit 243-1 randomly determines a new traffic allocation destination from among the terminal devices 20-2 and 20-3. Here, the allocation control unit 243-1 randomly determines a terminal device 20 that has not been selected as a traffic allocation destination as the traffic allocation destination. For example, the allocation control unit 243-1 determines the terminal device 20-3 as the traffic allocation destination.

[0057] The allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the terminal device 20-3 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20-3. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 244-1 allocates the traffic volume indicated by the traffic volume information to the terminal device 20-3 (step S106).

[0058] Specifically, the allocation unit 244-1 transmits traffic to the terminal device 20-3 via the PAN communication unit 22-1. The PAN communication unit 22-3 of the terminal device 20-3 receives the traffic transmitted from the terminal device 20-1. In response to receiving the traffic, the communication control unit 246-3 of the terminal device 20-3 controls the RAN communication unit 21-3 to transmit a connection request to the base station device 10. The RAN communication unit 21-3 of the terminal device 20-3 transmits the connection request to the base station device 10 under the control of the communication control unit 246-3 (step S107).

[0059] The base station device 10 receives a connection request transmitted from the terminal device 20-3. The base station device 10 transmits a reference signal to the terminal device 20-3 in response to the received connection request (step S108). This establishes a connection between the terminal device 20-3 and the base station device 10. The base station device 10 acquires radio state information for the terminal device 20-3 based on the connection request transmitted from the terminal device 20-3 (step S109). The base station device 10 transmits the acquired radio state information for the terminal device 20-3 to the terminal device 20-1 (step S110).

[0060] The RAN communication unit 21-1 of the terminal device 20-1 receives the radio state information of the terminal device 20-3 transmitted from the base station device 10. The communication control unit 246-1 stores the received radio state information of the terminal device 20-3 in the group terminal information storage unit 25.

[0061] The cooperative terminal determiner 245-1 determines a cooperative terminal based on the wireless state information stored in the group terminal information storage unit 25 (step S111). Here, it is assumed that the cooperative terminal determiner 245-1 determines the terminal device 20-2 as the cooperative terminal.

[0062] The cooperative terminal determination unit 245-1 notifies the communication control unit 246-1 that the terminal device 20-2 has been determined to be a cooperative terminal. In response to the notification from the cooperative terminal determination unit 245-1, the communication control unit 246-1 generates a determination notification addressed to the terminal device 20-2. For example, the communication control unit 246-1 generates a determination notification that includes a command to operate the terminal device as a cooperative terminal.

[0063] The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the determination notification generated by the communication control unit 246-1 to the terminal device 20-2. The PAN communication unit 22-1 transmits the determination notification to the terminal device 20-2 in accordance with the control of the communication control unit 246-1. The PAN communication unit 22-2 of the terminal device 20-2 receives the determination notification transmitted from the terminal device 20-1. In response to the received determination notification, the operation control unit 240-2 recognizes that its own device has been determined as a cooperative terminal. In this case, the operation control unit 240 of the terminal device 20-2 sets the operation mode of its own device to cooperative operation mode.

[0064] The allocation control unit 243-1 of the terminal device 20-1 determines the amount of allocated data to be allocated to the terminal device 20-2, which is a cooperative terminal. The allocation control unit 243-1 outputs information indicating the determined amount of allocated data to the communication control unit 246-1. The communication control unit 246-1 divides the transmission data in accordance with the information indicating the amount of allocated data output from the allocation control unit 243-1 (step S112). The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the divided data to be transmitted by the cooperative terminal to the terminal device 20-2, which is a cooperative terminal. The PAN communication unit 22-1 transmits the divided data to the terminal device 20-2, which is a cooperative terminal, in accordance with the control of the communication control unit 246-1 (step S113).

[0065] The PAN communication unit 22-2 of the terminal device 20-2 receives the divided data transmitted from the terminal device 20-1. The operation control unit 240-2 controls the RAN communication unit 21-2 to transmit the received divided data to the base station device 10. The RAN communication unit 21-2 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-2 (step S114).

[0066] The operation control unit 240-1 of the terminal device 20-1 controls the RAN communication unit 21-1 to transmit the divided data to the base station device 10. The RAN communication unit 21-1 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-1 (step S115). This allows the base station device 10 to receive the divided data transmitted from the transmitting terminal and each of the cooperative terminals.

[0067] (Operation example 2 in the first embodiment) Figure 4 is a sequence diagram showing the processing flow (part 2) of the wireless communication system 100 in the first embodiment. Note that the explanation of Figure 4 will be given using three terminal devices 20 as an example. Note that in explaining Figure 4, branch numbers will be added to distinguish the functional units of each terminal device 20. For example, the functional unit of terminal device 20-1 will be explained with "-1" added. Here, it is assumed that terminal device 20-1 is in a connected state with the base station device 10, and terminal devices 20-2 and 20-3 are not in a connected state with the base station device 10. Figure 4 is a diagram related to the above-mentioned [traffic volume allocation method 2].

[0068] The allocation control unit 243-1 of the terminal device 20-1 randomly determines the destination of traffic allocation from among the terminal devices 20-2 and 20-3. For example, the allocation control unit 243-1 determines the terminal device 20-2 as the destination of traffic allocation. The allocation control unit 243-1 determines the amount of traffic to allocate to the determined terminal device 20-2. The allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the determined destination of traffic allocation and information indicating the amount of traffic to be allocated.

[0069] For example, the allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the terminal device 20-2 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20-2. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 244-1 allocates the traffic volume indicated by the traffic volume information to the terminal device 20-2 (step S201).

[0070] Specifically, the allocation unit 244-1 transmits traffic to the terminal device 20-2 via the PAN communication unit 22-1. The PAN communication unit 22-2 of the terminal device 20-2 receives the traffic transmitted from the terminal device 20-1. In response to receiving the traffic, the communication control unit 246-2 of the terminal device 20-2 controls the RAN communication unit 21-2 to transmit a connection request to the base station device 10. The RAN communication unit 21-2 of the terminal device 20-2 transmits the connection request to the base station device 10 under the control of the communication control unit 246-2 (step S202).

[0071] The base station device 10 receives a connection request transmitted from the terminal device 20-2. The base station device 10 transmits a reference signal to the terminal device 20-2 in response to the received connection request (step S203). The RAN communication unit 21-2 of the terminal device 20-2 receives the reference signal transmitted from the base station device 10. As a result, the terminal device 20-2 and the base station device 10 are connected. The radio state information acquisition unit 241-2 of the terminal device 20-2 acquires radio state information based on the received reference signal (step S204).

[0072] The communication control unit 246-2 controls the PAN communication unit 22-2 to transmit the wireless state information acquired by the wireless state information acquisition unit 241-2 to the terminal device 20-1. The PAN communication unit 22-2 transmits the wireless state information to the terminal device 20-1 in accordance with the control of the communication control unit 246-2 (step S205). The PAN communication unit 22-1 of the terminal device 20-1 receives the wireless state information transmitted from the terminal device 20-2. The communication control unit 246-1 stores the received wireless state information of the terminal device 20-2 in the group terminal information storage unit 25.

[0073] The allocation control unit 243 determines whether the quality degradation condition is satisfied based on the wireless state information of the terminal device 20-2 stored in the group terminal information storage unit 25 (step S206). It is assumed here that the quality degradation condition is satisfied. In this case, the allocation control unit 243 randomly determines a new traffic allocation destination from among the terminal devices 20-2 and 20-3. Here, the allocation control unit 243-1 randomly determines a terminal device 20 that has not been selected as a traffic allocation destination as the traffic allocation destination. For example, the allocation control unit 243-1 determines the terminal device 20-3 as the traffic allocation destination.

[0074] The allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the terminal device 20-3 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20-3. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 244-1 allocates the traffic volume indicated by the traffic volume information to the terminal device 20-3 (step S207).

[0075] Specifically, the allocation unit 244-1 transmits traffic to the terminal device 20-3 via the PAN communication unit 22-1. The PAN communication unit 22-3 of the terminal device 20-3 receives the traffic transmitted from the terminal device 20-1. In response to receiving the traffic, the communication control unit 246-3 of the terminal device 20-3 controls the RAN communication unit 21-3 to transmit a connection request to the base station device 10. The RAN communication unit 21-3 of the terminal device 20-3 transmits the connection request to the base station device 10 under the control of the communication control unit 246-3 (step S208).

[0076] The base station device 10 receives a connection request transmitted from the terminal device 20-3. The base station device 10 transmits a reference signal to the terminal device 20-3 in response to the received connection request (step S209). This establishes a connection between the terminal device 20-3 and the base station device 10. The base station device 10 acquires radio state information for the terminal device 20-3 based on the connection request transmitted from the terminal device 20-3 (step S210). The base station device 10 transmits the acquired radio state information for the terminal device 20-3 to the terminal device 20-1 (step S211).

[0077] The RAN communication unit 21-1 of the terminal device 20-1 receives the radio state information of the terminal device 20-3 transmitted from the base station device 10. The communication control unit 246-1 stores the received radio state information of the terminal device 20-3 in the group terminal information storage unit 25.

[0078] The cooperative terminal determiner 245-1 determines a cooperative terminal based on the wireless state information stored in the group terminal information storage unit 25 (step S212). Here, it is assumed that the cooperative terminal determiner 245-1 determines the terminal device 20-2 as the cooperative terminal.

[0079] The cooperative terminal determination unit 245-1 notifies the communication control unit 246-1 that the terminal device 20-2 has been determined to be a cooperative terminal. In response to the notification from the cooperative terminal determination unit 245-1, the communication control unit 246-1 generates a determination notification addressed to the terminal device 20-2. For example, the communication control unit 246-1 generates a determination notification that includes a command to operate the terminal device as a cooperative terminal.

[0080] The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the determination notification generated by the communication control unit 246-1 to the terminal device 20-2. The PAN communication unit 22-1 transmits the determination notification to the terminal device 20-2 in accordance with the control of the communication control unit 246-1. The PAN communication unit 22-2 of the terminal device 20-2 receives the determination notification transmitted from the terminal device 20-1. In response to the received determination notification, the operation control unit 240-2 recognizes that its own device has been determined as a cooperative terminal. In this case, the operation control unit 240 of the terminal device 20-2 sets the operation mode of its own device to cooperative operation mode.

[0081] The allocation control unit 243-1 of the terminal device 20-1 determines the amount of allocated data to be allocated to the terminal device 20-2, which is a cooperative terminal. The allocation control unit 243-1 outputs information indicating the determined amount of allocated data to the communication control unit 246-1. The communication control unit 246-1 divides the transmission data in accordance with the information indicating the amount of allocated data output from the allocation control unit 243-1 (step S213). The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the divided data to be transmitted by the cooperative terminal to the terminal device 20-2, which is a cooperative terminal. The PAN communication unit 22-1 transmits the divided data to the terminal device 20-2, which is a cooperative terminal, in accordance with the control of the communication control unit 246-1 (step S214).

[0082] The PAN communication unit 22-2 of the terminal device 20-2 receives the divided data transmitted from the terminal device 20-1. The operation control unit 240-2 controls the RAN communication unit 21-2 to transmit the received divided data to the base station device 10. The RAN communication unit 21-2 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-2 (step S215).

[0083] The operation control unit 240-1 of the terminal device 20-1 controls the RAN communication unit 21-1 to transmit the divided data to the base station device 10. The RAN communication unit 21-1 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-1 (step S216). This allows the base station device 10 to receive the divided data transmitted from the transmitting terminal and each of the cooperative terminals.

[0084] (Operation example 3 in the first embodiment) Figure 5 is a sequence diagram showing the processing flow (part 3) of the wireless communication system 100 in the first embodiment. In the explanation of Figure 3, three terminal devices 20 will be used as an example. In the explanation of Figure 5, branch numbers will be added to distinguish the functional units of each terminal device 20. For example, the functional unit of terminal device 20-1 will be added with "-1" in the explanation. Here, it is assumed that terminal device 20-1 is in a connected state with the base station device 10, and terminal devices 20-2 and 20-3 are not in a connected state with the base station device 10. Figure 5 is a diagram related to the above-mentioned [Traffic volume allocation method 3].

[0085] The allocation control unit 243-1 of the terminal device 20-1 randomly determines the destination of traffic allocation from among the terminal devices 20-2 and 20-3. For example, the allocation control unit 243-1 determines the terminal device 20-2 as the destination of traffic allocation. The allocation control unit 243-1 determines the amount of traffic to allocate to the determined terminal device 20-2. The allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the determined destination of traffic allocation and information indicating the amount of traffic to be allocated.

[0086] For example, the allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the terminal device 20-2 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20-2. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 244-1 allocates the traffic volume indicated by the traffic volume information to the terminal device 20-2 (step S301).

[0087] Specifically, the allocation unit 244-1 transmits traffic to the terminal device 20-2 via the PAN communication unit 22-1. The PAN communication unit 22-2 of the terminal device 20-2 receives the traffic transmitted from the terminal device 20-1. In response to receiving the traffic, the communication control unit 246-2 of the terminal device 20-2 controls the RAN communication unit 21-2 to transmit a connection request to the base station device 10. The RAN communication unit 21-2 of the terminal device 20-2 transmits the connection request to the base station device 10 under the control of the communication control unit 246-2 (step S302).

[0088] The base station device 10 receives a connection request transmitted from the terminal device 20-2. The base station device 10 transmits a reference signal to the terminal device 20-2 as a response to the received connection request (step S303). The RAN communication unit 21-2 of the terminal device 20-2 receives the reference signal transmitted from the base station device 10. As a result, the terminal device 20-2 and the base station device 10 are connected. The base station device 10 may perform the processes of steps S104 and 105 in FIG. 3. That is, the base station device 10 may measure radio state information of the terminal device 20-2 and transmit the measured radio state information to the terminal device 20-1.

[0089] The terminal information acquisition unit 242-2 of the terminal device 20-2 acquires the terminal status information (step S304). The communication control unit 246-2 controls the PAN communication unit 22-2 to transmit the terminal status information acquired by the terminal information acquisition unit 242-2 to the terminal device 20-1. The PAN communication unit 22-2 transmits the terminal status information to the terminal device 20-1 in accordance with the control of the communication control unit 246-2 (step S305). The PAN communication unit 22-1 of the terminal device 20-1 receives the terminal status information transmitted from the terminal device 20-2. The communication control unit 246-1 stores the received terminal status information of the terminal device 20-2 in the group terminal information storage unit 25.

[0090] The allocation control unit 243 determines whether or not there has been a change in the installation status based on the terminal status information of the terminal device 20-2 stored in the group terminal information storage unit 25 (step S306). It is assumed here that there has been a change in the installation status. In this case, the allocation control unit 243 randomly determines a new traffic allocation destination from among the terminal devices 20-2 and 20-3. Here, the allocation control unit 243-1 randomly determines a terminal device 20 that has not been selected as a traffic allocation destination as the traffic allocation destination. For example, the allocation control unit 243-1 determines the terminal device 20-3 as the traffic allocation destination.

[0091] The allocation control unit 243-1 notifies the allocation unit 244-1 of information indicating the terminal device 20-3 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20-3. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 244-1 allocates the traffic volume indicated by the traffic volume information to the terminal device 20-3 (step S307).

[0092] Specifically, the allocation unit 244-1 transmits traffic to the terminal device 20-3 via the PAN communication unit 22-1. The PAN communication unit 22-3 of the terminal device 20-3 receives the traffic transmitted from the terminal device 20-1. In response to receiving the traffic, the communication control unit 246-3 of the terminal device 20-3 controls the RAN communication unit 21-3 to transmit a connection request to the base station device 10. The RAN communication unit 21-3 of the terminal device 20-3 transmits the connection request to the base station device 10 under the control of the communication control unit 246-3 (step S308).

[0093] The base station device 10 receives a connection request transmitted from the terminal device 20-3. The base station device 10 transmits a reference signal to the terminal device 20-3 in response to the received connection request (step S309). This establishes a connection between the terminal device 20-3 and the base station device 10. The base station device 10 acquires radio state information for the terminal device 20-3 based on the connection request transmitted from the terminal device 20-3 (step S310). The base station device 10 transmits the acquired radio state information for the terminal device 20-3 to the terminal device 20-1 (step S311).

[0094] The RAN communication unit 21-1 of the terminal device 20-1 receives the radio state information of the terminal device 20-3 transmitted from the base station device 10. The communication control unit 246-1 stores the received radio state information of the terminal device 20-3 in the group terminal information storage unit 25.

[0095] The cooperative terminal determiner 245-1 determines a cooperative terminal based on the wireless state information stored in the group terminal information storage unit 25 (step S312). Here, it is assumed that the cooperative terminal determiner 245-1 determines the terminal device 20-2 as the cooperative terminal.

[0096] The cooperative terminal determination unit 245-1 notifies the communication control unit 246-1 that the terminal device 20-2 has been determined to be a cooperative terminal. In response to the notification from the cooperative terminal determination unit 245-1, the communication control unit 246-1 generates a determination notification addressed to the terminal device 20-2. For example, the communication control unit 246-1 generates a determination notification that includes a command to operate the terminal device as a cooperative terminal.

[0097] The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the determination notification generated by the communication control unit 246-1 to the terminal device 20-2. The PAN communication unit 22-1 transmits the determination notification to the terminal device 20-2 in accordance with the control of the communication control unit 246-1. The PAN communication unit 22-2 of the terminal device 20-2 receives the determination notification transmitted from the terminal device 20-1. In response to the received determination notification, the operation control unit 240-2 recognizes that its own device has been determined as a cooperative terminal. In this case, the operation control unit 240 of the terminal device 20-2 sets the operation mode of its own device to cooperative operation mode.

[0098] The allocation control unit 243-1 of the terminal device 20-1 determines the amount of allocated data to be allocated to the terminal device 20-2, which is a cooperative terminal. The allocation control unit 243-1 outputs information indicating the determined amount of allocated data to the communication control unit 246-1. The communication control unit 246-1 divides the transmission data in accordance with the information indicating the amount of allocated data output from the allocation control unit 243-1 (step S313). The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the divided data to be transmitted by the cooperative terminal to the terminal device 20-2, which is a cooperative terminal. The PAN communication unit 22-1 transmits the divided data to the terminal device 20-2, which is a cooperative terminal, in accordance with the control of the communication control unit 246-1 (step S314).

[0099] The PAN communication unit 22-2 of the terminal device 20-2 receives the divided data transmitted from the terminal device 20-1. The operation control unit 240-2 controls the RAN communication unit 21-2 to transmit the received divided data to the base station device 10. The RAN communication unit 21-2 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-2 (step S315).

[0100] The operation control unit 240-1 of the terminal device 20-1 controls the RAN communication unit 21-1 to transmit the divided data to the base station device 10. The RAN communication unit 21-1 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-1 (step S316). This allows the base station device 10 to receive the divided data transmitted from the transmitting terminal and each of the cooperative terminals.

[0101] According to the wireless communication system 100 configured as described above, a source terminal, which is one of the multiple terminal devices 20, includes an allocation unit 244 that allocates traffic to one or more terminal devices 20 among the multiple terminal devices 20 that are candidates for performing cooperative operation. One or more terminal devices 20 (terminal devices 20 other than the source terminal) include a wireless state information acquisition unit 241 that acquires wireless state information by wirelessly communicating with the base station device 10 in accordance with the traffic allocated by the source terminal, and a PAN communication unit 22 that transmits the wireless state information acquired by the wireless state information acquisition unit 241 to the source terminal. This allows even candidate terminals that are not connected to the base station device 10 to periodically connect to the base station device 10 and acquire wireless state information. This makes it possible for each candidate terminal to efficiently acquire information used for selecting a cooperative terminal.

[0102] Furthermore, in the wireless communication system 100, when there are multiple candidate terminals, the allocation unit 244 allocates traffic to each candidate terminal in turn at predetermined time intervals. In this way, traffic can be allocated efficiently to all candidate terminals. This allows even candidate terminals that are not connected to the base station device 10 to periodically connect to the base station device 10 and obtain radio state information. This makes it possible for each candidate terminal to efficiently obtain information used to select a cooperative terminal.

[0103] Furthermore, in the wireless communication system 100, when a quality degradation condition is satisfied based on the wireless state information of the cooperative terminals that are performing cooperative operation, the allocation unit 244 allocates traffic to each candidate terminal that is not connected to the base station device 10. This makes it possible to obtain information for selecting a new cooperative terminal when the communication quality of a terminal device 20 that is already operating as a cooperative terminal deteriorates.

[0104] Furthermore, in the wireless communication system 100, the allocation unit 244 allocates traffic to each candidate terminal not connected to the base station device 10 when a condition indicating a change in the state of the wireless communication device performing the cooperative operation is satisfied, based on the terminal state information of the cooperative terminal performing the cooperative operation. This allows information for selecting a new cooperative terminal to be acquired when a condition indicating a change in the state of the wireless communication device is satisfied. If the state of a terminal device 20 already operating as a cooperative terminal changes, this may affect the cooperative operation depending on the state. For example, a change in the installation state of the terminal device 20 may affect the quality of wireless communication. Therefore, by acquiring information for selecting a new cooperative terminal, a new cooperative terminal can be determined. This makes it possible to suppress the impact of changes in the installation state of the terminal device 20.

[0105] Second Embodiment In the first embodiment, a configuration was described in which a terminal device controls traffic allocation, whereas in the second embodiment, a configuration will be described in which a server located on the same network as the terminal device controls traffic allocation.

[0106] Fig. 6 is a diagram showing an example of the configuration of a wireless communication system 100a according to the second embodiment. The wireless communication system 100a includes a base station device 10, a plurality of terminal devices 20a, and a server 30. Note that the number of terminal devices 20a may be any number as long as there is more than one, and the number of servers 30 is not particularly limited. Fig. 6 shows an example in which the wireless communication system 100 includes three terminal devices 20a and one server 30.

[0107] The wireless communication system 100a has a different configuration from the wireless communication system 100 in that a server 30 is located in the same network as the multiple terminal devices 20a. The following description will focus on the differences from the wireless communication system 100.

[0108] The terminal device 20a is a terminal that communicates in a frequency band of millimeter waves or higher. The terminal device 20a forms a group with one or more other terminal devices 20a and a server 30. The terminal devices 20a and the server 30 belonging to each group form a PAN network by forming a wireless or wired PAN link between the terminal devices 20a belonging to the same group or between the terminal device 20a and the server 30. FIG. 6 shows an example in which the wireless communication system 100a has one group G1, and the group G1 includes three terminal devices 20a-1 to 20a-3 and one server 30. Note that while FIG. 6 shows one group, the wireless communication system 100a may have multiple groups. The terminal device 20a is one aspect of a wireless communication device.

[0109] The server 30 is a device located on the same network (PAN) as each terminal device 20a. The server 30 is a device that can receive power from an external source (AC power source). The server 30 is configured using an information processing device such as a personal computer. The server 30 is one aspect of a wireless communication device. The server 30 performs communication between each terminal device 20a and the server 30.

[0110] The server 30 has a function of allocating and controlling traffic to enable each candidate terminal to communicate with the base station device 10. For example, the server 30 has a function of executing some of the processes shown in [Traffic Volume Allocation Method 1] to [Traffic Volume Allocation Method 3] described in the first embodiment (e.g., excluding determination of cooperative terminals).

[0111] Next, a method of allocating traffic volume for allowing each candidate terminal to perform communication with the base station device 10 in the second embodiment will be described.

[0112] [Traffic Volume Allocation Method 1] Traffic volume allocation method 1 is a method for periodically and randomly allocating part of traffic to a candidate terminal that is not connected to the base station device 10, thereby connecting the candidate terminal to the base station device 10 and acquiring radio state information. Here, (Operation 1) to (Operation 6) are shown and explained.

[0113] (Operation 1) The source terminal is set to terminal device 20a-1, and terminal devices 20a-2 and 20a-3 are set to candidate terminals. Note that terminal device 20a-1 is a transmitting terminal and is in a connected state with base station device 10. (Operation 2) The server 30 randomly selects a cooperative terminal from among terminal devices 20a-2 and 20a-3. Here, it is assumed that terminal device 20a-2 is selected. As a result, terminal devices 20a-1 and 20a-2 are in a connected state with base station device 10, and terminal device 20a-3 is not in a connected state with base station device 10.

[0114] (Operation 3) The server 30 allocates a portion of the traffic at regular time intervals to a candidate terminal (e.g., terminal device 20a-3) that is not connected to the base station device 10. This generates traffic from the terminal device 20a-3. If there are multiple candidate terminals, the server 30 allocates a portion of the traffic to the other candidate terminals in turn at regular time intervals, thereby generating traffic from each candidate terminal. (Operation 4) The base station device 10 measures radio state information of the candidate terminals that are connected to the base station device 10, and notifies the server 30 of information indicating the measured radio state information.

[0115] (Operation 5) The server 30 notifies each terminal device 20a of the radio state information of each candidate terminal obtained from the base station device 10. Note that the server 30 may notify only the transmitting terminal of the radio state information of each candidate terminal obtained from the base station device 10. (Operation 6) The transmitting terminal among the terminal devices 20a determines a new cooperative terminal based on the radio state information of each candidate terminal.

[0116] [Traffic Volume Allocation Method 2] Traffic volume allocation method 2 is a method for, when a quality degradation occurs in a terminal device 20a that is already operating as a cooperative terminal, allocating traffic to a candidate terminal that is not in a connected state with the base station device 10, thereby connecting the candidate terminal and the base station device 10 and acquiring radio state information. Here, (Operation 1) to (Operation 7) will be described.

[0117] (Operation 1) The source terminal is set to terminal device 20a-1, and terminal devices 20a-2 and 20a-3 are set to candidate terminals. Note that terminal device 20a-1 is a transmitting terminal and is in a connected state with base station device 10. (Operation 2) The server 30 randomly selects a cooperative terminal from among terminal devices 20a-2 and 20a-3. Here, it is assumed that terminal device 20a-2 is selected. As a result, terminal devices 20a-1 and 20a-2 are in a connected state with base station device 10, and terminal device 20a-3 is not in a connected state with base station device 10.

[0118] (Operation 3) The base station device 10 measures the radio state information of a candidate terminal (e.g., terminal device 20a-2) that is in a connected state. The base station device 10 notifies the server 30 of the measured radio state information. (Operation 4) When the server 30 determines that the quality degradation condition is met based on the radio state information of the terminal device 20a-2, it allocates a portion of the traffic to a candidate terminal (e.g., terminal device 20a-3) that is not in a connected state with the base station device 10. This causes traffic to be generated from the terminal device 20a-3. Note that if there are multiple candidate terminals, the server 30 may generate traffic from each candidate terminal by allocating a portion of the traffic to the other candidate terminals in turn at regular intervals.

[0119] (Operation 5) The base station device 10 measures the radio state information of the newly connected candidate terminal (for example, terminal device 20a-3) and notifies the server 30 of the measured radio state information. (Operation 6) The server 30 notifies each terminal device 20a of the radio state information of each candidate terminal obtained from the base station device 10. Note that the server 30 may notify only the transmitting terminal of the radio state information of each candidate terminal obtained from the base station device 10. (Operation 7) The transmitting terminal among the terminal devices 20a determines a new cooperative terminal based on the radio state information of each candidate terminal.

[0120] [Traffic Volume Allocation Method 3] Traffic volume allocation method 3 is a method for allocating traffic to a candidate terminal that is not connected to the base station device 10 when the installation state of a cooperative terminal that is already operating as a cooperative terminal changes, thereby connecting the candidate terminal and the base station device 10 and acquiring radio state information. The purpose of this method is to detect connection instability of terminal device 20a that is already being used as a cooperative terminal from physical information. Here, (Operation 1) to (Operation 7) are shown and explained.

[0121] (Operation 1) The source terminal is set to terminal device 20a-1, and terminal devices 20a-2 and 20a-3 are set to candidate terminals. Note that terminal device 20a-1 is a transmitting terminal and is in a connected state with base station device 10. (Operation 2) The server 30 randomly selects a cooperative terminal from among terminal devices 20a-2 and 20a-3. Here, it is assumed that terminal device 20a-2 is selected. As a result, terminal devices 20a-1 and 20a-2 are in a connected state with base station device 10, and terminal device 20a-3 is not in a connected state with base station device 10.

[0122] (Operation 3) The terminal device 20a-2 measures terminal state information and notifies the server 30 of the measured terminal state information. (Operation 4) The server 30 determines whether or not the installation state of the terminal device 20a connected to the base station device 10 has changed, based on the terminal state information notified from the terminal device 20a (e.g., terminal device 20a-2) that is connected to the base station device 10. For example, if the amount of change in acceleration exceeds a threshold, the server 30 determines that the installation state of the terminal device 20a-2 has changed. Note that, although the determination based on acceleration is shown as an example here, the determination may also be based on location information.

[0123] (Operation 5) When the server 30 determines that the installation state of the terminal device 20a connected to the base station device 10 has changed, the server 30 allocates a portion of the traffic to a candidate terminal (e.g., the terminal device 20a-3) that is not connected to the base station device 10. This causes traffic to be generated from the terminal device 20a-3. Note that if there are multiple candidate terminals, the server 30 may allocate a portion of the traffic to the other candidate terminals in turn at regular time intervals, thereby generating traffic from each candidate terminal.

[0124] (Operation 6) The base station device 10 measures the radio state information of the newly connected candidate terminal (for example, terminal device 20a-3) and notifies the server 30 of the measured radio state information. (Operation 7) The server 30 notifies each terminal device 20a of the radio state information of each candidate terminal obtained from the base station device 10. Note that the server 30 may notify only the transmitting terminal of the radio state information of each candidate terminal obtained from the base station device 10. (Operation 8) The transmitting terminal among the terminal devices 20a determines a new cooperative terminal based on the radio state information of each candidate terminal.

[0125] 7 is a diagram showing an example of the configuration of the server 30 according to the second embodiment. The server 30 includes a communication unit 31 and a control unit 32.

[0126] The communication unit 31 communicates between each terminal device 20a and the base station device 10. The communication unit 31 includes, for example, a RAN communication unit and a PAN communication unit. The RAN communication unit is a wireless interface for the RAN. The RAN communication unit communicates with the base station device 10. The PAN communication unit is a wireless interface for the PAN. The PAN communication unit communicates with the terminal device 20a in the group. The communication unit 31 transmits traffic to, for example, a candidate terminal, and receives terminal status information and wireless status information from the candidate terminal.

[0127] The control unit 32 controls the entire server 30. The control unit 32 is configured using one or more processors such as a CPU and one or more memories. The control unit 32 realizes the functions of an allocation control unit 321, an allocation unit 322, and a communication control unit 323 by the one or more processors executing programs.

[0128] The allocation control unit 321 determines candidate terminals to which traffic is to be allocated and the amount of traffic to be allocated to the candidate terminals.

[0129] The allocation unit 322 allocates the determined traffic volume to the candidate terminals to which the traffic has been allocated, as determined by the allocation control unit 321 .

[0130] The communication control unit 323 controls the communication of the communication unit 31. The communication control unit 323 controls, for example, the communication unit 31 to transmit traffic to each terminal device 20a.

[0131] 8 is a diagram showing an example of the configuration of a terminal device 20a in the second embodiment. The terminal device 20a includes a RAN communication unit 21, a PAN communication unit 22, a reception processing unit 23, a control unit 24a, and a group terminal information storage unit 25. The configuration of the terminal device 20a differs from that of the terminal device 20 in that the terminal device 20a includes a control unit 24a instead of the control unit 24. The other configuration of the terminal device 20a is the same as that of the terminal device 20. The following description will focus on the differences from the first embodiment.

[0132] The control unit 24a controls the entire terminal device 20a. The control unit 24a is configured using one or more processors such as a CPU and one or more memories. The control unit 24a realizes the functions of an operation control unit 240, a radio state information acquisition unit 241, a terminal information acquisition unit 242, a cooperative terminal determination unit 245, and a communication control unit 246a by having the one or more processors execute programs.

[0133] The communication control unit 246a controls communication between the RAN communication unit 21 and the PAN communication unit 22. For example, when the own device operates in a transmitting terminal mode, the communication control unit 246a controls the PAN communication unit 22 to send a predetermined notification to the other terminal device 20a. For example, when the own device operates in a cooperative operation mode, the communication control unit 246a may control the PAN communication unit 22 to send terminal status information and wireless status information to the transmitting terminal.

[0134] The communication control unit 246 a controls the RAN communication unit 21 to transmit the traffic allocated by the server 30 to the base station device 10 .

[0135] (Operation Example 1 in Second Embodiment) Next, the processing flow of the wireless communication system 100a in the second embodiment will be described. First, the processing flow of the wireless communication system 100a relating to the above-mentioned [Traffic Volume Allocation Method 1] will be described. In the description, subnumbers will be added to distinguish the functional units of each terminal device 20a. For example, the functional unit of the terminal device 20a-1 will be added with "-1" in the description. Here, it is assumed that the terminal device 20a-1 is in a connected state with the base station device 10, and the terminal devices 20a-2 and 20a-3 are not in a connected state with the base station device 10.

[0136] The allocation control unit 321 of the server 30 randomly determines the destination of traffic allocation from among the terminal devices 20a-2 and 20a-3. For example, the allocation control unit 321 determines the terminal device 20a-2 as the destination of traffic allocation. The allocation control unit 321 determines the amount of traffic to be allocated to the determined terminal device 20a-2. The allocation control unit 321 notifies the allocation unit 322 of information indicating the determined destination of traffic allocation and information indicating the amount of traffic to be allocated.

[0137] For example, the allocation control unit 321 notifies the allocation unit 322 of information indicating the terminal device 20a-2 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20a-2. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 322 allocates the traffic volume indicated by the traffic volume information to the terminal device 20a-2.

[0138] Specifically, the allocation unit 322 transmits traffic to the terminal device 20a-2 via the communication unit 31. The PAN communication unit 22-2 of the terminal device 20a-2 receives the traffic transmitted from the server 30. In response to receiving the traffic, the communication control unit 246-2 of the terminal device 20a-2 controls the RAN communication unit 21-2 to transmit a connection request to the base station device 10. The RAN communication unit 21-2 of the terminal device 20a-2 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 246-2.

[0139] The base station device 10 receives a connection request transmitted from the terminal device 20a-2. The base station device 10 transmits a reference signal to the terminal device 20a-2 in response to the received connection request. This establishes a connection between the terminal device 20a-2 and the base station device 10. The base station device 10 acquires radio state information of the terminal device 20a-2 based on the connection request transmitted from the terminal device 20a-2. The base station device 10 transmits the acquired radio state information of the terminal device 20a-2 to the server 30.

[0140] The communication unit 31 of the server 30 receives the wireless state information of the terminal device 20a-2 transmitted from the base station device 10. The communication control unit 323 controls the communication unit 31 to notify each terminal device 20a of the received wireless state information of the terminal device 20a-2. Each terminal device 20a stores the wireless state information of the terminal device 20a-2 notified from the server 30 in the group terminal information storage unit 25.

[0141] Next, after a certain period of time has elapsed, the allocation control unit 321 randomly determines the new traffic allocation destination from among the terminal devices 20a-2 and 20a-3. Here, the allocation control unit 321 randomly determines the terminal device 20a that has not been selected as the traffic allocation destination as the traffic allocation destination. For example, the allocation control unit 321 determines the terminal device 20a-3 as the traffic allocation destination.

[0142] The allocation control unit 321 notifies the allocation unit 322 of information indicating the terminal device 20a-3 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20a-3. The allocation unit 322 allocates the traffic volume indicated by the traffic volume information to the terminal device 20a-3 based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated.

[0143] Specifically, the allocation unit 322 transmits traffic to the terminal device 20a-3 via the communication unit 31. The PAN communication unit 22-3 of the terminal device 20a-3 receives the traffic transmitted from the server 30. In response to receiving the traffic, the communication control unit 246-3 of the terminal device 20a-3 controls the RAN communication unit 21-3 to transmit a connection request to the base station device 10. The RAN communication unit 21-3 of the terminal device 20a-3 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 246-3.

[0144] The base station device 10 receives a connection request transmitted from the terminal device 20a-3. The base station device 10 transmits a reference signal to the terminal device 20a-3 in response to the received connection request. This establishes a connection between the terminal device 20a-3 and the base station device 10. The base station device 10 acquires radio state information of the terminal device 20a-3 based on the connection request transmitted from the terminal device 20a-3. The base station device 10 transmits the acquired radio state information of the terminal device 20a-3 to the server 30.

[0145] The communication unit 31 of the server 30 receives the wireless state information of the terminal device 20a-3 transmitted from the base station device 10. The communication control unit 323 controls the communication unit 31 to notify each terminal device 20a of the received wireless state information of the terminal device 20a-3. Each terminal device 20a stores the wireless state information of the terminal device 20a-3 notified from the server 30 in the group terminal information storage unit 25.

[0146] Now, suppose that data to be transmitted occurs in the terminal device 20a-1. In this case, the terminal device 20a-1 enters the transmitting terminal mode. The cooperative terminal determiner 245-1 of the terminal device 20a-1 determines a cooperative terminal based on the radio state information stored in the group terminal information storage unit 25. Now, suppose that the cooperative terminal determiner 245-1 determines the terminal device 20a-2 as the cooperative terminal.

[0147] The cooperative terminal determiner 245-1 notifies the communication controller 246-1 that the terminal device 20a-2 has been determined to be a cooperative terminal. In response to the notification from the cooperative terminal determiner 245-1, the communication controller 246-1 generates a determination notification addressed to the terminal device 20a-2. For example, the communication controller 246-1 generates a determination notification that includes a command to operate the terminal device as a cooperative terminal.

[0148] The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the determination notification generated by the communication control unit 246-1 to the terminal device 20a-2. The PAN communication unit 22-1 transmits the determination notification to the terminal device 20a-2 in accordance with the control of the communication control unit 246-1. The PAN communication unit 22-2 of the terminal device 20a-2 receives the determination notification transmitted from the terminal device 20a-1. In response to the received determination notification, the operation control unit 240-2 recognizes that its own device has been determined as a cooperative terminal. In this case, the operation control unit 240 of the terminal device 20a-2 sets the operation mode of its own device to cooperative operation mode.

[0149] Next, the allocation control unit 321 of the server 30 determines an allocation destination and an amount of allocated data. The allocation control unit 321 outputs information indicating the determined allocation destination and amount of allocated data to the communication control unit 323. The communication control unit 323 controls the communication unit 31 to transmit the information indicating the allocation destination and amount of allocated data output from the allocation control unit 321 to the terminal device 20a-1, which is the transmitting terminal. The communication unit 31 transmits the information indicating the allocation destination and amount of allocated data to the terminal device 20a-1 in accordance with the control of the communication control unit 323.

[0150] The PAN communication unit 22-1 of the terminal device 20a-1 receives information indicating the allocation destination and the amount of allocated data transmitted from the server 30. The communication control unit 246-1 divides the transmission data in accordance with the received information indicating the amount of allocated data. The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the divided data to be transmitted by the cooperative terminal to the terminal device 20a-2, which is also a cooperative terminal. The PAN communication unit 22-1 transmits the divided data to the terminal device 20a-2, which is also a cooperative terminal, in accordance with the control of the communication control unit 246-1.

[0151] The PAN communication unit 22-2 of the terminal device 20a-2 receives the divided data transmitted from the terminal device 20a-1. The operation control unit 240-2 controls the RAN communication unit 21-2 to transmit the received divided data to the base station device 10. The RAN communication unit 21-2 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-2.

[0152] The operation control unit 240-1 of the terminal device 20a-1 controls the RAN communication unit 21-1 to transmit the divided data to the base station device 10. The RAN communication unit 21-1 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-1. This allows the base station device 10 to receive the divided data transmitted from the transmitting terminal and each of the cooperative terminals.

[0153] (Operation Example 2 in Second Embodiment) Next, the processing flow of the wireless communication system 100a related to the above-mentioned [Traffic Volume Allocation Method 2] will be described. In the description, sub-numbers will be added to distinguish the functional units of each terminal device 20a. For example, the functional unit of the terminal device 20a-1 will be added with "-1" in the description. Here, it is assumed that the terminal device 20a-1 is in a connected state with the base station device 10, and the terminal devices 20a-2 and 20a-3 are not in a connected state with the base station device 10.

[0154] The allocation control unit 321 of the server 30 randomly determines the destination of traffic allocation from among the terminal devices 20a-2 and 20a-3. For example, the allocation control unit 321 determines the terminal device 20a-2 as the destination of traffic allocation. The allocation control unit 321 determines the amount of traffic to be allocated to the determined terminal device 20a-2. The allocation control unit 321 notifies the allocation unit 322 of information indicating the determined destination of traffic allocation and information indicating the amount of traffic to be allocated.

[0155] For example, the allocation control unit 321 notifies the allocation unit 322 of information indicating the terminal device 20a-2 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20a-2. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 322 allocates the traffic volume indicated by the traffic volume information to the terminal device 20a-2.

[0156] Specifically, the allocation unit 322 transmits traffic to the terminal device 20a-2 via the communication unit 31. The PAN communication unit 22-2 of the terminal device 20a-2 receives the traffic transmitted from the server 30. In response to receiving the traffic, the communication control unit 246-2 of the terminal device 20a-2 controls the RAN communication unit 21-2 to transmit a connection request to the base station device 10. The RAN communication unit 21-2 of the terminal device 20a-2 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 246-2.

[0157] The base station device 10 receives a connection request transmitted from the terminal device 20a-2. The base station device 10 transmits a reference signal to the terminal device 20a-2 in response to the received connection request. The RAN communication unit 21-2 of the terminal device 20a-2 receives the reference signal transmitted from the base station device 10. As a result, the terminal device 20a-2 and the base station device 10 are connected. The radio state information acquisition unit 241-2 of the terminal device 20a-2 acquires radio state information based on the received reference signal.

[0158] The communication control unit 246-2 controls the PAN communication unit 22-2 to transmit the wireless state information acquired by the wireless state information acquisition unit 241-2 to the server 30. The PAN communication unit 22-2 transmits the wireless state information to the server 30 in accordance with the control of the communication control unit 246-2. The communication unit 31 of the server 30 receives the wireless state information transmitted from the terminal device 20a-2.

[0159] The allocation control unit 321 determines whether or not the quality degradation condition is satisfied based on the received radio state information of the terminal device 20a-2. Here, it is assumed that the quality degradation condition is satisfied. In this case, the allocation control unit 321 randomly determines the new traffic allocation destination from among the terminal devices 20a-2 and 20a-3. Here, the allocation control unit 321 randomly determines the terminal device 20a that has not been selected as the traffic allocation destination as the traffic allocation destination. For example, the allocation control unit 321 determines the terminal device 20a-3 as the traffic allocation destination.

[0160] The allocation control unit 321 notifies the allocation unit 322 of information indicating the terminal device 20a-3 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20a-3. The allocation unit 322 allocates the traffic volume indicated by the traffic volume information to the terminal device 20a-3 based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated.

[0161] Specifically, the allocation unit 322 transmits traffic to the terminal device 20a-3 via the communication unit 31. The PAN communication unit 22-3 of the terminal device 20a-3 receives the traffic transmitted from the server 30. In response to receiving the traffic, the communication control unit 246-3 of the terminal device 20a-3 controls the RAN communication unit 21-3 to transmit a connection request to the base station device 10. The RAN communication unit 21-3 of the terminal device 20a-3 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 246-3.

[0162] The base station device 10 receives a connection request transmitted from the terminal device 20a-3. The base station device 10 transmits a reference signal to the terminal device 20a-3 in response to the received connection request. This establishes a connection between the terminal device 20a-3 and the base station device 10. The base station device 10 acquires radio state information of the terminal device 20a-3 based on the connection request transmitted from the terminal device 20a-3. The base station device 10 transmits the acquired radio state information of the terminal device 20a-3 to the server 30.

[0163] The communication unit 31 of the server 30 receives the wireless state information of the terminal device 20a-3 transmitted from the base station device 10. The communication control unit 323 controls the communication unit 31 to notify each terminal device 20a of the received wireless state information of the terminal device 20a-3. Each terminal device 20a stores the wireless state information of the terminal device 20a-3 notified from the server 30 in the group terminal information storage unit 25.

[0164] The cooperative terminal determiner 245-1 of the terminal device 20a-1 determines a cooperative terminal based on the radio state information stored in the group terminal information storage unit 25. Here, it is assumed that the cooperative terminal determiner 245-1 determines the terminal device 20a-2 as a cooperative terminal.

[0165] The cooperative terminal determiner 245-1 notifies the communication controller 246-1 that the terminal device 20a-2 has been determined to be a cooperative terminal. In response to the notification from the cooperative terminal determiner 245-1, the communication controller 246-1 generates a determination notification addressed to the terminal device 20a-2. For example, the communication controller 246-1 generates a determination notification that includes a command to operate the terminal device as a cooperative terminal.

[0166] The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the determination notification generated by the communication control unit 246-1 to the terminal device 20a-2. The PAN communication unit 22-1 transmits the determination notification to the terminal device 20a-2 in accordance with the control of the communication control unit 246-1. The PAN communication unit 22-2 of the terminal device 20a-2 receives the determination notification transmitted from the terminal device 20a-1. In response to the received determination notification, the operation control unit 240-2 recognizes that its own device has been determined as a cooperative terminal. In this case, the operation control unit 240 of the terminal device 20a-2 sets the operation mode of its own device to cooperative operation mode.

[0167] Next, the allocation control unit 321 of the server 30 determines an allocation destination and an amount of allocated data. The allocation control unit 321 outputs information indicating the determined allocation destination and amount of allocated data to the communication control unit 323. The communication control unit 323 controls the communication unit 31 to transmit the information indicating the allocation destination and amount of allocated data output from the allocation control unit 321 to the terminal device 20a-1, which is the transmitting terminal. The communication unit 31 transmits the information indicating the allocation destination and amount of allocated data to the terminal device 20a-1 in accordance with the control of the communication control unit 323.

[0168] The PAN communication unit 22-1 of the terminal device 20a-1 receives information indicating the allocation destination and the amount of allocated data transmitted from the server 30. The communication control unit 246-1 divides the transmission data in accordance with the received information indicating the amount of allocated data. The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the divided data to be transmitted by the cooperative terminal to the terminal device 20a-2, which is also a cooperative terminal. The PAN communication unit 22-1 transmits the divided data to the terminal device 20a-2, which is also a cooperative terminal, in accordance with the control of the communication control unit 246-1.

[0169] The PAN communication unit 22-2 of the terminal device 20a-2 receives the divided data transmitted from the terminal device 20a-1. The operation control unit 240-2 controls the RAN communication unit 21-2 to transmit the received divided data to the base station device 10. The RAN communication unit 21-2 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-2.

[0170] The operation control unit 240-1 of the terminal device 20a-1 controls the RAN communication unit 21-1 to transmit the divided data to the base station device 10. The RAN communication unit 21-1 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-1. This allows the base station device 10 to receive the divided data transmitted from the transmitting terminal and each of the cooperative terminals.

[0171] (Operation Example 3 in Second Embodiment) Next, the processing flow of the wireless communication system 100a related to the above-mentioned [Traffic Volume Allocation Method 3] will be described. In the description, sub-numbers will be added to distinguish the functional units of each terminal device 20a. For example, the functional unit of the terminal device 20a-1 will be added with "-1" in the description. Here, it is assumed that the terminal device 20a-1 is in a connected state with the base station device 10, and the terminal devices 20a-2 and 20a-3 are not in a connected state with the base station device 10.

[0172] The allocation control unit 321 of the server 30 randomly determines the destination of traffic allocation from among the terminal devices 20a-2 and 20a-3. For example, the allocation control unit 321 determines the terminal device 20a-2 as the destination of traffic allocation. The allocation control unit 321 determines the amount of traffic to be allocated to the determined terminal device 20a-2. The allocation control unit 321 notifies the allocation unit 322 of information indicating the determined destination of traffic allocation and information indicating the amount of traffic to be allocated.

[0173] For example, the allocation control unit 321 notifies the allocation unit 322 of information indicating the terminal device 20a-2 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20a-2. Based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated, the allocation unit 322 allocates the traffic volume indicated by the traffic volume information to the terminal device 20a-2.

[0174] Specifically, the allocation unit 322 transmits traffic to the terminal device 20a-2 via the communication unit 31. The PAN communication unit 22-2 of the terminal device 20a-2 receives the traffic transmitted from the server 30. In response to receiving the traffic, the communication control unit 246-2 of the terminal device 20a-2 controls the RAN communication unit 21-2 to transmit a connection request to the base station device 10. The RAN communication unit 21-2 of the terminal device 20a-2 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 246-2.

[0175] The base station device 10 receives a connection request transmitted from the terminal device 20a-2. The base station device 10 transmits a reference signal to the terminal device 20a-2 as a response to the received connection request. The RAN communication unit 21-2 of the terminal device 20a-2 receives the reference signal transmitted from the base station device 10. As a result, the terminal device 20a-2 and the base station device 10 are connected. The base station device 10 may measure radio state information of the terminal device 20a-2 and transmit the measured radio state information to the server 30.

[0176] The terminal information acquisition unit 242-2 of the terminal device 20a-2 acquires terminal status information. The communication control unit 246-2 controls the PAN communication unit 22-2 to transmit the terminal status information acquired by the terminal information acquisition unit 242-2 to the server 30. The PAN communication unit 22-2 transmits the terminal status information to the server 30 in accordance with the control of the communication control unit 246-2. The communication unit 31 of the server 30 receives the terminal status information transmitted from the terminal device 20a-2.

[0177] The allocation control unit 321 determines whether or not there has been a change in the installation state based on the received terminal state information of the terminal device 20a-2. Here, it is assumed that there has been a change in the installation state. In this case, the allocation control unit 321 randomly determines the new traffic allocation destination from among the terminal devices 20a-2 and 20a-3. Here, the allocation control unit 243-1 randomly determines the terminal device 20a that has not been selected as the traffic allocation destination as the traffic allocation destination. For example, the allocation control unit 321 determines the terminal device 20a-3 as the traffic allocation destination.

[0178] The allocation control unit 321 notifies the allocation unit 322 of information indicating the terminal device 20a-3 as the traffic allocation destination and information indicating the traffic volume to be allocated to the terminal device 20a-3. The allocation unit 322 allocates the traffic volume indicated by the traffic volume information to the terminal device 20a-3 based on the notified information indicating the traffic allocation destination and the information indicating the traffic volume to be allocated.

[0179] Specifically, the allocation unit 322 transmits traffic to the terminal device 20a-3 via the communication unit 31. The PAN communication unit 22-3 of the terminal device 20a-3 receives the traffic transmitted from the server 30. In response to receiving the traffic, the communication control unit 246-3 of the terminal device 20a-3 controls the RAN communication unit 21-3 to transmit a connection request to the base station device 10. The RAN communication unit 21-3 of the terminal device 20a-3 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 246-3.

[0180] The base station device 10 receives a connection request transmitted from the terminal device 20a-3. The base station device 10 transmits a reference signal to the terminal device 20a-3 in response to the received connection request. This establishes a connection between the terminal device 20a-3 and the base station device 10. The base station device 10 acquires radio state information of the terminal device 20a-3 based on the connection request transmitted from the terminal device 20a-3. The base station device 10 transmits the acquired radio state information of the terminal device 20a-3 to the server 30.

[0181] The communication unit 31 of the server 30 receives the wireless state information of the terminal device 20a-3 transmitted from the base station device 10. The communication control unit 323 controls the communication unit 31 to notify each terminal device 20a of the received wireless state information of the terminal device 20a-3. Each terminal device 20a stores the wireless state information of the terminal device 20a-3 notified from the server 30 in the group terminal information storage unit 25.

[0182] The cooperative terminal determiner 245-1 of the terminal device 20a-1 determines a cooperative terminal based on the radio state information stored in the group terminal information storage unit 25. Here, it is assumed that the cooperative terminal determiner 245-1 determines the terminal device 20a-2 as a cooperative terminal.

[0183] The cooperative terminal determiner 245-1 notifies the communication controller 246-1 that the terminal device 20a-2 has been determined to be a cooperative terminal. In response to the notification from the cooperative terminal determiner 245-1, the communication controller 246-1 generates a determination notification addressed to the terminal device 20a-2. For example, the communication controller 246-1 generates a determination notification that includes a command to operate the terminal device as a cooperative terminal.

[0184] The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the determination notification generated by the communication control unit 246-1 to the terminal device 20a-2. The PAN communication unit 22-1 transmits the determination notification to the terminal device 20a-2 in accordance with the control of the communication control unit 246-1. The PAN communication unit 22-2 of the terminal device 20a-2 receives the determination notification transmitted from the terminal device 20a-1. In response to the received determination notification, the operation control unit 240-2 recognizes that its own device has been determined as a cooperative terminal. In this case, the operation control unit 240 of the terminal device 20a-2 sets the operation mode of its own device to cooperative operation mode.

[0185] Next, the allocation control unit 321 of the server 30 determines an allocation destination and an amount of allocated data. The allocation control unit 321 outputs information indicating the determined allocation destination and amount of allocated data to the communication control unit 323. The communication control unit 323 controls the communication unit 31 to transmit the information indicating the allocation destination and amount of allocated data output from the allocation control unit 321 to the terminal device 20a-1, which is the transmitting terminal. The communication unit 31 transmits the information indicating the allocation destination and amount of allocated data to the terminal device 20a-1 in accordance with the control of the communication control unit 323.

[0186] The PAN communication unit 22-1 of the terminal device 20a-1 receives information indicating the allocation destination and the amount of allocated data transmitted from the server 30. The communication control unit 246-1 divides the transmission data in accordance with the received information indicating the amount of allocated data. For example, the communication control unit 246-1 divides the transmission data in accordance with the number of its own device and the number of cooperative terminals. Here, the data division ratio is set arbitrarily. The communication control unit 246-1 controls the PAN communication unit 22-1 to transmit the divided data to be transmitted by the cooperative terminal to the terminal device 20a-2, which is a cooperative terminal. The PAN communication unit 22-1 transmits the divided data to the terminal device 20a-2, which is a cooperative terminal, in accordance with the control of the communication control unit 246-1.

[0187] The PAN communication unit 22-2 of the terminal device 20a-2 receives the divided data transmitted from the terminal device 20a-1. The operation control unit 240-2 controls the RAN communication unit 21-2 to transmit the received divided data to the base station device 10. The RAN communication unit 21-2 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-2.

[0188] The operation control unit 240-1 of the terminal device 20a-1 controls the RAN communication unit 21-1 to transmit the divided data to the base station device 10. The RAN communication unit 21-1 transmits the divided data to the base station device 10 in accordance with the control of the communication control unit 246-1. This allows the base station device 10 to receive the divided data transmitted from the transmitting terminal and each of the cooperative terminals.

[0189] The wireless communication system 100a configured as above can achieve the same effects as those of the first embodiment.

[0190] Furthermore, in the wireless communication system 100a, the server 30, which can receive a stable power supply, determines the cooperative terminals that bear the processing load and the amount of data to be allocated. Therefore, the battery-powered terminal device 20a only needs to transmit and receive data. This makes it possible to conserve power in the terminal device 20a.

[0191] (Variation of the Second Embodiment) In the configuration described above, the server 30 is located within the same network as each terminal device 20a. However, the server 30 does not have to be located within the same network as each terminal device 20a. For example, the server 30 may be configured to communicate with each terminal device 20a via the base station device 10. In this configuration, the server 30 transmits radio state information of each candidate terminal used to determine a new cooperative terminal to the transmitting terminal via the base station device 10. Furthermore, the server 30 transmits information indicating the amount of traffic allocated for generating traffic, etc., to the candidate terminals that are not in a connected state via the base station device 10.

[0192] Each terminal device 20a collects information necessary for allocating and controlling traffic volume in the server 30 and transmits it to the server 30 via the base station device 10. The information necessary for allocating and controlling traffic volume in the server 30 includes, for example, radio state information of each candidate terminal and terminal state information of each candidate terminal. The operation performed by the server 30 is the same as the operation described in the second embodiment, except that communication with each terminal device 20a is performed via the base station device 10.

[0193] (Modification common to the first and second embodiments) In some of the above-described embodiments, the base station device 10 has been configured to measure radio state information of candidate terminals, but each candidate terminal may measure radio state information based on a reference signal transmitted in response to a connection request transmitted from the base station device 10. In this case, each candidate terminal shares the measured radio state information with each terminal device 20 in the group or the server 30.

[0194] The terminal devices 20, 20a and server 30 described above may be implemented by a computer. In this case, a program for implementing the functions may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed. Note that the term "computer system" as used herein includes hardware such as an operating system (OS) and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, magneto-optical disks, read-only memories (ROMs), and CD-ROMs, as well as storage devices such as hard disks built into computer systems.

[0195] Furthermore, the term "computer-readable recording medium" may include a medium that dynamically stores a program for a short period of time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, or a medium that stores a program for a certain period of time, such as a volatile memory within a computer system that serves as a server or client in such a case. The program may also be one that realizes part of the above-mentioned functions, or one that can realize the above-mentioned functions in combination with a program already stored in the computer system, or one that can be realized using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0196] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention.

[0197] The present invention is applicable to wireless access networks.

[0198] DESCRIPTION OF SYMBOLS 10... Base station device, 20, 20a... Terminal device, 21... RAN communication unit, 22... PAN communication unit, 23... Reception processing unit, 24, 24a, 32... Control unit, 25... Group terminal information storage unit, 30... Server, 31... Communication unit, 100, 100a... Wireless communication system, 240... Operation control unit, 241... Wireless state information acquisition unit, 242... Terminal information acquisition unit, 243, 321... Allocation control unit, 244, 322... Allocation unit, 245... Cooperative terminal determination unit, 246, 246a, 323... Communication control unit

Claims

1. A wireless communication system comprising a plurality of wireless communication devices and a base station device, wherein an allocating wireless communication device, which is one of the plurality of wireless communication devices, comprises: an allocating unit that allocates traffic to one or more wireless communication devices that are candidates for performing cooperative operation and are not connected to the base station device; and the one or more wireless communication devices comprise: a wireless state information acquiring unit that acquires wireless state information, which is information regarding the quality of wireless communication, by performing wireless communication with the base station device in accordance with the traffic allocated by the allocating wireless communication device; and a communication unit that transmits the wireless state information acquired by the wireless state information acquiring unit to the allocating wireless communication device.

2. The wireless communication system according to claim 1, wherein, when there are one or more wireless communication devices that are candidates for performing the cooperative operation, the allocation unit allocates traffic to each wireless communication device in turn at predetermined time intervals.

3. The wireless communication system according to claim 1 or 2, wherein the allocation unit allocates traffic to one or more wireless communication devices that are not connected to the base station device and are candidates for executing the cooperative operation when a condition that the quality of wireless communication indicated in the wireless status information of the wireless communication device executing the cooperative operation has deteriorated is met.

4. The wireless communication system described in claim 1 or 2, wherein the allocation unit allocates traffic to one or more wireless communication devices that are not connected to the base station device and are candidates for performing the cooperative operation when a condition indicating that the state of the wireless communication device performing the cooperative operation has changed is met based on terminal state information, which is information regarding the state of the wireless communication device performing the cooperative operation.

5. The wireless communication system according to claim 4, further comprising an allocation control unit that determines, when the change in acceleration exceeds a threshold, that a condition indicating that the state of the wireless communication device executing the cooperative operation has changed is met, and when the condition is met, the allocation unit allocates traffic to one or more wireless communication devices that are not connected to the base station device and are candidates for executing the cooperative operation.

6. The wireless communication system according to claim 1 or 2, wherein the plurality of wireless communication devices include a plurality of terminal devices and one or more servers, and the allocation unit is provided in at least one of the plurality of terminal devices or the one or more servers.

7. A wireless communication method performed by a wireless communication system comprising a plurality of wireless communication devices and a base station device, wherein an allocating wireless communication device, which is one of the plurality of wireless communication devices, allocates traffic to one or more wireless communication devices that are candidates for performing cooperative operation and are not connected to the base station device, and the one or more wireless communication devices acquire wireless status information, which is information regarding the quality of wireless communication, by performing wireless communication with the base station device in accordance with the traffic allocated by the allocating wireless communication device, and transmits the acquired wireless status information to the allocating wireless communication device.

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