Wireless communication system and cooperative terminal determination method

Abstract

This wireless communication system comprises a plurality of wireless communication devices and a base station device, wherein any one of the plurality of wireless communication devices includes a cooperative terminal determination unit that calculates a correlation value between the device itself and another wireless communication device by using either wireless state information regarding the quality of the wireless communication of each wireless communication device, or terminal state information regarding the state of each wireless communication device, and determines, on the basis of the calculated correlation value, one or more cooperative terminals for executing cooperative operation.　

Description

Wireless communication system and method for determining cooperative terminals

[0001] The present invention relates to a wireless communication system and a method for determining cooperative terminals.

[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] As mentioned above, activating all terminals and having them perform cooperative operation is expected to improve the stability of millimeter waves. However, depending on the location of the terminals, their contribution rate may be low. Therefore, even if all terminals are activated, keeping terminals with low contribution rates activated all the time is undesirable from the perspective of power consumption. Therefore, a technology that efficiently selects terminals to perform cooperative operation is desired.

[0005] In view of the above circumstances, an object of the present invention is to provide a technique that can efficiently select a terminal that is to execute a cooperative operation.

[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 one of the plurality of wireless communication devices is equipped with a cooperative terminal determination unit that calculates a correlation value between the device itself and other wireless communication devices using either wireless status information, which is information regarding the quality of wireless communication of each wireless communication device, or terminal status information, which is information regarding the status of each wireless communication device, and determines one or more cooperative terminals to perform cooperative operation based on the calculated correlation value.

[0007] One aspect of the present invention is a cooperative terminal determination method performed by a wireless communication system including a plurality of wireless communication devices and a base station device, in which any one of the plurality of wireless communication devices calculates a correlation value between itself and other wireless communication devices using either wireless state information, which is information about the quality of wireless communication of each wireless communication device, or terminal state information, which is information about the state of each wireless communication device, and determines one or more cooperative terminals to perform cooperative operation based on the calculated correlation value.

[0008] According to the present invention, it becomes possible to efficiently select terminals that are to execute cooperative operations.

[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 the flow of processing in the wireless communication system in the first embodiment; FIG. 4 is a diagram showing an example of the configuration of a wireless communication system in a second embodiment; FIG. 5 is a diagram showing an example of the configuration of a server in the second embodiment; and FIG. 6 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] A 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. The method for determining a cooperative terminal will be described later. At least one terminal device 20 out of the multiple terminal devices 20 needs to have the function of determining a cooperative terminal and the function of allocating transmitted and received traffic, which will be described later. Therefore, it is not necessary for all of the multiple terminal devices 20 to have the function of determining a cooperative terminal and the function of allocating transmitted and received traffic, which will be described later.

[0018] For example, the function of determining cooperative terminals and the function of allocating transmission and reception traffic, which will be described later, may be provided by the master terminal in the group, or by another terminal device 20. In the following explanation, for simplicity's sake, an example will be given in which the master terminal is the transmitting terminal and the transmitting terminal has the function of determining cooperative terminals and the function of allocating transmission and reception traffic, which will be described later. Note that, although the master terminal and the transmitting terminal are shown as the same terminal device 20 here, the master terminal and the transmitting terminal may be different terminal devices 20. For example, it is also conceivable that the master terminal is a terminal device 20 having the function of allocating traffic, and the transmitting terminal is a terminal device 20 having data to be transmitted. The terminal device 20 is one aspect of a wireless communication device.

[0019] 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 candidate terminal is, for example, a terminal device 20 other than the master 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 (for example, 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.

[0020] The candidate terminals share the acquired radio state information with the master terminal. As a method for sharing the radio state information with the transmitting terminal, for example, all candidate terminals may share the information directly with the transmitting terminal through terminal-to-terminal communication (communication via PAN), or may share the information with the transmitting terminal via the base station device 10. When sharing the information with the master terminal via the base station device 10, all candidate terminals transmit their radio state information to the base station device 10. The base station device 10 transmits the obtained radio state information to the master terminal.

[0021] Furthermore, all candidate terminals may share their own terminal status information (e.g., location information) with the master terminal. As a method for sharing the terminal status information with the master terminal, for example, all candidate terminals may share the information directly with the master terminal through terminal-to-terminal communication (communication via PAN), or may share the information with the master terminal via the base station device 10. When sharing the information with the master terminal via the base station device 10, all candidate terminals transmit their terminal status information to the base station device 10. The base station device 10 transmits the obtained terminal status information to the master terminal.

[0022] The master terminal acquires at least either radio state information or terminal state information from all candidate terminals belonging to the group using the method described above. The master terminal determines a cooperative terminal from among the multiple candidate terminals based on the received radio state information or terminal state information. The master terminal then determines the amount of traffic (hereinafter referred to as the "allocated data amount") to be allocated to each of the determined cooperative terminals, and transmits information indicating the determined allocated data amount to the cooperative terminals. Note that if the master terminal and the transmitting terminal are different, the master terminal notifies the transmitting terminal of information indicating the allocated data amount for each cooperative terminal. The transmitting terminal transmits data to be transmitted according to the allocated data amount to each cooperative terminal based on the information indicating the allocated data amount for each cooperative terminal notified by the master terminal.

[0023] 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.

[0024] 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.

[0025] 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 and wireless status information to the terminal devices 20 in the group. The PAN communication unit 22 also receives, for example, terminal status information and wireless status information transmitted from other terminal devices 20.

[0026] 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 .

[0027] 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, a cooperative terminal determination unit 243, a communication control unit 244, and an allocation control unit 245 by the one or more processors executing programs.

[0028] 1 represents the functional configuration when the terminal device 20 is a master terminal. As described above, some terminal devices 20 may not have the function of determining a cooperative terminal and the function of allocating transmitted and received traffic, and therefore some terminal devices 20 may not have the functions of the cooperative terminal determination unit 243 and the allocation control unit 245.

[0029] The operation control unit 240 sets the operation mode of the own device. Specifically, the operation control unit 240 sets the operation mode of the own device to operate in either a master terminal mode or a cooperative operation mode. The master terminal mode is a mode for operating as a master terminal. The cooperative operation mode is a mode for performing cooperative operation with other terminal devices 20.

[0030] The operation control unit 240 may set the operation mode of its own device to the master terminal mode, for example, when data to be transmitted is generated, or may set the operation mode of its own device to the master terminal mode when it is determined to be the master terminal among other terminal devices 20. For example, when it 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.

[0031] The radio state information acquisition unit 241 acquires radio state information based on a reference signal obtained through wireless communication with the base station device 10. The radio state information acquisition unit 241 acquires 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.

[0032] 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.

[0033] When the cooperative terminal determiner 243 operates in the master terminal mode, it determines a cooperative terminal from among the terminal devices 20 in the group. Specifically, the cooperative terminal determiner 243 uses either radio state information or terminal state information obtained from each terminal device 20 to calculate a correlation value between the cooperative terminal (master terminal) and the other terminal devices 20, and determines a cooperative terminal based on the calculated correlation value. The cooperative terminal determiner 243 may use the following two methods to determine a cooperative terminal.

[0034] (First Method for Determining a Cooperative Terminal) The index of the terminal device 20 (transmitting terminal) that is the source of the transmitted data is assumed to be k. The cooperative terminal determiner 243 calculates the time-series information of the radio state information (for example, received power information) of the terminal device 20-k as R ｋThe cooperative terminal determiner 243 calculates the correlation value between the time series information of the radio state information of the terminal device 20-k and the time series information of the radio state information of the other terminal devices 20-n (n = 1, ..., N, N is the number of terminal devices 20 belonging to one user) based on the following formula (1):

[0035]

[0036] In addition, the cooperative terminal determination unit 243 may calculate the correlation value between the time series information of the terminal status information (e.g., location information) of the terminal device 20-k and the time series information of the terminal status information (e.g., location information) of the other terminal devices 20-n based on the above equation (1).

[0037] The cooperative terminal determination unit 243 selects the terminal device 20-n' specified based on the following equation (2) as the cooperative terminal. Specifically, the cooperative terminal determination unit 243 determines the terminal device 20-n' having the lowest correlation value with the time-series information of the radio state information or the time-series information of the terminal device 20-k as the cooperative terminal.

[0038]

[0039] (Second Method for Determining a Cooperative Terminal) The cooperative terminal determiner 243 uses different information as time-series information of the radio state information used to calculate the correlation value in the above-mentioned (first method for determining a cooperative terminal), and determines the terminal device 20-n' with the lowest correlation value as the cooperative terminal. Here, the different information as time-series information of the radio state information means other information included in the radio state information, such as calculating the correlation value between RSSI and RSRP.

[0040] It is expected that the position of the terminal device 20 may change over time. If the position of the terminal device 20 changes, it is possible that the contribution rate in the cooperative operation may increase. By adding a terminal device 20 with a high contribution rate as a cooperative terminal, cooperative operation can be performed more efficiently. Therefore, when the installation position of a terminal device 20 that is not a cooperative terminal is changed, or at a predetermined timing, the cooperative terminal determination unit 243 adds a terminal device 20 that satisfies the following additional conditions as a cooperative terminal.

[0041] For example, terminal state information is used as a method for detecting a change in the installation location of a terminal device 20. Specifically, the cooperative terminal determination unit 243 may detect that the installation location of a terminal device 20 that is not a cooperative terminal has been changed when the acceleration sensor value obtained from the terminal device 20 that is not a cooperative terminal changes by more than a threshold value when comparing the acceleration sensor value obtained from the terminal device 20 that is not a cooperative terminal with the average value of the acceleration sensors of all terminal devices 20 carried by the individual.

[0042] The cooperative terminal determiner 243 uses either the radio state information or the terminal state information obtained from each terminal device 20 to calculate a correlation value between its own device (master terminal) and the other terminal devices 20, and adds cooperative terminals based on the calculated correlation value. The cooperative terminal determiner 243 can add cooperative terminals in the following two ways.

[0043] (First method for adding a cooperative terminal (addition condition)) Here, terminal device 20-k' is a candidate for addition to the cooperative terminal (terminal device 20 that is not a cooperative terminal), and terminal device 20-k (k = 1, 2) is a terminal device 20 that belongs to the cooperative terminal group. A terminal device 20 that belongs to the cooperative terminal group is a terminal device 20 that has been determined to be a cooperative terminal by the cooperative terminal determination unit 243.

[0044] The cooperative terminal determination unit 243 calculates the time series information of the radio state information (for example, received power information) of the terminal device 20-k′ as R ｋ´ The cooperative terminal determiner 243 calculates the correlation value between the time-series information of the radio state information (for example, received power information) of the terminal device 20-k′ and the time-series information of the radio state information of the terminal device 20-k based on the following equation (3):

[0045]

[0046] In addition, the cooperative terminal determination unit 243 may calculate the correlation value between the time series information of the terminal status information (e.g., location information) of the terminal device 20-k' and the time series information of the terminal status information (e.g., location information) of the terminal device 20-k based on the above equation (3).

[0047] Then, the cooperative terminal determiner 243 calculates the average value of the correlation values ​​based on the following equation (4).

[0048]

[0049] If the calculated average value of the correlation values ​​is equal to or less than a predetermined threshold, the cooperative terminal determiner 243 adds the terminal device 20-k' to the cooperative terminal group. That is, the cooperative terminal determiner 243 adds the terminal device 20-k' as a new cooperative terminal.

[0050] (Second method of adding a cooperative terminal (additional conditions)) The cooperative terminal determination unit 243 calculates the average value of the correlation values ​​using different information as the time series information of the radio state information used to calculate the correlation values ​​in the above-mentioned (first method of adding a cooperative terminal), and adds the terminal device 20-k' to the group of cooperative terminals if the calculated average value of the correlation values ​​is below a predetermined threshold.

[0051] It is expected that the location of the terminal device 20 may change over time. If the location of a terminal device 20 determined as a cooperative terminal is changed, it is possible that its contribution rate in cooperative operation may have decreased. It is not efficient to use a cooperative terminal with a low contribution rate for cooperative operation. Therefore, when the installation location of the cooperative terminal is changed, or at a predetermined timing, the cooperative terminal determination unit 243 removes a cooperative terminal that satisfies the following removal condition from the cooperative terminal group.

[0052] (Method for excluding cooperative terminals (removal conditions)) The cooperative terminal determination unit 243 calculates a correlation value of time-series information of radio state information or time-series information of terminal state information acquired by each cooperative terminal belonging to the cooperative terminal group. Next, the cooperative terminal determination unit 243 calculates the average value of the correlation values. If the average value of the correlation values ​​exceeds a threshold, the cooperative terminal determination unit 243 excludes each cooperative terminal from the cooperative terminal group.

[0053] The communication control unit 244 controls communication between the RAN communication unit 21 and the PAN communication unit 22. For example, when the own device operates in a master terminal mode, the communication control unit 244 controls the PAN communication unit 22 to transmit a predetermined notification to the other terminal devices 20. For example, when the own device operates in a cooperative operation mode, the communication control unit 244 may control the PAN communication unit 22 to transmit terminal status information and wireless status information to the transmitting terminal.

[0054] The allocation control unit 245 determines the cooperative terminal to which transmission data is to be allocated and the amount of data to be allocated. The allocation control unit 245 may determine the cooperative terminal determined by the cooperative terminal determination unit 243 as the cooperative terminal to which data is to be allocated. Furthermore, the allocation control unit 245 determines the amount of traffic to be allocated (amount of allocated data) in accordance with terminal status information or radio status information obtained from the cooperative terminal. For example, the allocation control unit 245 may determine the amount of traffic in accordance with the performance of the cooperative terminal (e.g., remaining battery power) by referring to the terminal status information obtained from the cooperative terminal, or may determine the amount of traffic in accordance with the radio environment of the cooperative terminal (e.g., received power) by referring to the radio status information obtained from the cooperative terminal.

[0055] 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.

[0056] (Example of operation in the first embodiment) Fig. 3 is a sequence diagram showing the flow of processing in the wireless communication system 100 in the first embodiment. In the explanation of Fig. 3, three terminal devices 20 will be used as an example. In the explanation of Fig. 3, 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, the case where terminal device 20-1 is the master terminal will be explained as an example.

[0057] Assume that data to be transmitted occurs in the terminal device 20-1 (step S101). In response to the occurrence of the data to be transmitted, the communication control unit 244-1 of the terminal device 20-1 controls the RAN communication unit 21-1 to transmit a connection request to the base station device 10. The RAN communication unit 21-1 transmits the connection request to the base station device 10 under the control of the communication control unit 244-1 (step S102).

[0058] The base station device 10 receives a connection request transmitted from the terminal device 20-1. The base station device 10 transmits a reference signal to the terminal device 20-1 in response to the received connection request (step S103). The RAN communication unit 21-1 of the terminal device 20-1 receives the reference signal transmitted from the base station device 10. As a result, the terminal device 20-1 and the base station device 10 are connected. The radio state information acquisition unit 241-1 of the terminal device 20-1 may acquire radio state information based on the received reference signal.

[0059] Thereafter, the communication control unit 244-1 of the terminal device 20-1 controls the PAN communication unit 22-1 to transmit a request signal (a provision request in FIG. 3) for sharing the wireless state information from each of the terminal devices 20 belonging to the same group. The PAN communication unit 22-1 transmits the request signal to each of the terminal devices 20-2 and 20-3 belonging to the same group in accordance with the control of the communication control unit 244-1 (step S104).

[0060] The PAN communication unit 22-2 of the terminal device 20-2 receives the request signal transmitted from the terminal device 20-1. In response to receiving the request signal, the communication control unit 244-2 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 transmits the connection request to the base station device 10 under the control of the communication control unit 244-2 (step S105).

[0061] 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 S106). 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 S107).

[0062] The communication control unit 244-2 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, which is the master terminal. 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 244-2 (step S108). The PAN communication unit 22-1 of the terminal device 20-1 receives the wireless state information transmitted from the terminal device 20-2 and stores the received wireless state information in the group terminal information storage unit 25.

[0063] The PAN communication unit 22-3 of the terminal device 20-3 receives the request signal transmitted from the terminal device 20-1. In response to receiving the request signal, the communication control unit 244-3 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 transmits the connection request to the base station device 10 under the control of the communication control unit 244-3 (step S109).

[0064] 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 S110). The RAN communication unit 21-3 of the terminal device 20-3 receives the reference signal transmitted from the base station device 10. As a result, the terminal device 20-3 and the base station device 10 are connected. The radio state information acquisition unit 241-3 of the terminal device 20-3 acquires radio state information based on the received reference signal (step S111).

[0065] The communication control unit 244-3 controls the PAN communication unit 22-3 to transmit the wireless state information acquired by the wireless state information acquisition unit 241-3 to the terminal device 20-1, which is the master terminal. The PAN communication unit 22-3 transmits the wireless state information to the terminal device 20-1 in accordance with the control of the communication control unit 244-3 (step S112). The PAN communication unit 22-1 of the terminal device 20-1 receives the wireless state information transmitted from the terminal device 20-3 and stores the received wireless state information in the group terminal information storage unit 25.

[0066] The cooperative terminal determiner 243-1 of the terminal device 20-1 determines a cooperative terminal based on the wireless state information stored in the group terminal information storage unit 25 (step S113). Here, it is assumed that the cooperative terminal determiner 243-1 determines the terminal device 20-2 as the cooperative terminal.

[0067] The cooperative terminal determination unit 243-1 notifies the communication control unit 244-1 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 243-1, the communication control unit 244-1 generates a determination notification addressed to the terminal device 20-2. For example, the communication control unit 244-1 generates a determination notification that includes a command to operate the terminal device as a cooperative terminal.

[0068] The communication control unit 244-1 controls the PAN communication unit 22-1 to transmit the determination notification generated by the communication control unit 244-1 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 244-1. 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.

[0069] The terminal device 20-1 may transmit a decision notification to the terminal device 20-3 that was not determined as a cooperative terminal, including a notice that the terminal device 20-3 will not operate as a cooperative terminal. The terminal device 20-3 stops its startup in response to the decision notification transmitted from the terminal device 20-1. Stopping startup here means that only the functional units related to reception are operating and the operation of other functional units is stopped. This makes it possible to reduce the power consumption of the terminal device 20-3.

[0070] Next, the allocation control unit 245-1 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 245-1 outputs information indicating the determined amount of allocated data to the communication control unit 244-1. The communication control unit 244-1 divides the transmission data in accordance with the information indicating the amount of allocated data output from the allocation control unit 245-1 (step S114). The communication control unit 244-1 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. The PAN communication unit 22-1 transmits the divided data to the terminal device 20-2 in accordance with the control of the communication control unit 244-1 (step S115).

[0071] 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 244-2 (step S116).

[0072] 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 244-1 (step S117). This allows the base station device 10 to receive the divided data transmitted from the transmitting terminal and each of the cooperative terminals.

[0073] 3 shows a configuration in which the master terminal determines cooperative terminals using radio state information of each terminal device 20, but the master terminal may determine cooperative terminals using terminal state information of each terminal device 20. When using terminal state information, terminal devices 20 other than the master terminal (terminal devices 20-2 and 20-3) acquire the terminal state information and share it with the master terminal when they receive a request for terminal state information from the master terminal.

[0074] 3 shows a configuration in which terminal devices 20 (terminal devices 20-2 and 20-3) other than the master terminal acquire wireless state information by wirelessly communicating with the base station device 10 in response to a request for wireless state information from the master terminal. The terminal devices 20 (terminal devices 20-2 and 20-3) other than the master terminal may acquire and store wireless state information by periodically communicating wirelessly with the base station device 10, and may share the stored wireless state information with the master terminal in response to a request for wireless state information from the master terminal.

[0075] According to the wireless communication system 100 configured as described above, any one of the multiple terminal devices 20 includes a cooperative terminal determination unit 243 that calculates a correlation value between the master terminal and the other terminal devices 20 using either the wireless state information or the terminal state information of each terminal device 20, and determines one or more cooperative terminals to execute cooperative operation based on the calculated correlation value. This makes it possible to efficiently select terminals to execute cooperative operation. As a result, it is possible to improve the path diversity effect due to cooperation between the terminal devices 20.

[0076] Furthermore, in the wireless communication system 100, the cooperative terminal determination unit 243 determines the terminal device 20 with the lowest correlation value as the cooperative terminal. By determining the terminal device 20 with the smallest correlation with time fluctuations in throughput or terminal state as the cooperative terminal in this way, it is possible to improve the path diversity effect due to cooperation between the terminal devices 20.

[0077] Furthermore, in the wireless communication system 100, the cooperative terminal determination unit 243 calculates a correlation value between the radio state information or terminal state information of the cooperative terminal and the radio state information or terminal state information of a terminal device 20 that is not a cooperative terminal, and if the calculated correlation value is equal to or less than a threshold, adds the terminal device 20 that is not a cooperative terminal to the cooperative terminals. In this way, by adding a terminal device 20 that has little correlation with time fluctuations in throughput or terminal state as a cooperative terminal, it is possible to further improve the path diversity effect due to cooperation between the terminal devices 20.

[0078] Furthermore, in the wireless communication system 100, the cooperative terminal determination unit 243 calculates a correlation value using either the wireless state information or the terminal state information of each of the multiple cooperative terminals, and excludes the cooperative terminal from the cooperative terminal group if the calculated correlation value is equal to or greater than a threshold. In this way, by excluding cooperative terminals that have a high correlation with time fluctuations in throughput or terminal state, it is possible to leave only terminal devices 20 that have a low correlation with time fluctuations in throughput or terminal state as cooperative terminals. As a result, it is possible to improve the path diversity effect due to cooperation between terminal devices 20.

[0079] Second Embodiment In the first embodiment, a configuration was described in which a terminal device has a function for determining cooperative terminals and a function for allocating transmitted and received traffic. In contrast, in the second embodiment, a configuration will be described in which a server located on the same network as the terminal device has a function for determining cooperative terminals and a function for allocating transmitted and received traffic.

[0080] Fig. 4 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. 4 shows an example in which the wireless communication system 100 includes three terminal devices 20a and one server 30.

[0081] 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.

[0082] 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. 4 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. 4 shows one group, the wireless communication system 100a may have multiple groups. The terminal device 20a is one aspect of a wireless communication device.

[0083] The server 30 is a device located on the same network (PAN) as each terminal device 20a. The server 30 has a function to determine a cooperative terminal and a function to allocate transmission and reception traffic. For example, the server 30 has a function to execute the (first method for determining a cooperative terminal), (second method for determining a cooperative terminal), (first method for adding a cooperative terminal (additional condition)), (second method for adding a cooperative terminal (additional condition)), and (method for excluding a cooperative terminal (removal condition)) shown in the first embodiment.

[0084] Furthermore, the server 30 transmits information indicating the amount of data to be allocated to the transmitting terminal and each of the determined cooperative terminals. In this way, the server 30 provides the transmitting terminal and each of the determined cooperative terminals with information indicating the amount of data to be transmitted.

[0085] The server 30 is a device that can receive power from an external power source (AC power supply), and is configured using an information processing device such as a personal computer, etc. The server 30 is one aspect of a wireless communication device.

[0086] 5 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.

[0087] The communication unit 31 communicates with each terminal device 20a. The communication unit 31 is a wireless interface for a PAN. The communication unit 31 communicates with the terminal devices 20a in the group.

[0088] 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 a cooperative terminal determination unit 321, an allocation control unit 322, and a communication control unit 323 by the one or more processors executing programs.

[0089] The cooperative terminal determiner 321 performs the same processing as the cooperative terminal determiner 243 in the first embodiment. For example, the cooperative terminal determiner 321 determines cooperative terminals from among the terminal devices 20a in the group. Specifically, the cooperative terminal determiner 321 calculates correlation values ​​between the transmitting terminal and the other terminal devices 20a using either radio state information or terminal state information obtained from each terminal device 20a, and determines cooperative terminals based on the calculated correlation values. The method by which the cooperative terminal determiner 321 determines cooperative terminals is the same as in the first embodiment.

[0090] The cooperative terminal determiner 321 calculates a correlation value between the transmitting terminal and the other terminal devices 20a using either the radio state information or the terminal state information obtained from each terminal device 20a, and adds cooperative terminals based on the calculated correlation value. The method by which the cooperative terminal determiner 321 adds cooperative terminals is the same as in the first embodiment.

[0091] The cooperative terminal determination unit 321 calculates a correlation value of time-series information of radio state information or time-series information of terminal state information acquired by each cooperative terminal belonging to the cooperative terminal group. Next, the cooperative terminal determination unit 321 calculates an average value of the correlation values. If the average value of the correlation values ​​exceeds a threshold, the cooperative terminal determination unit 321 excludes each cooperative terminal from the cooperative terminal group.

[0092] The allocation control unit 322 determines the cooperative terminal to which the transmission data is to be allocated and the amount of data to be allocated to the transmitting terminal and the cooperative terminal. The allocation control unit 322 simply determines the cooperative terminal determined by the cooperative terminal determination unit 321 as the cooperative terminal to which the transmission data is to be allocated. Furthermore, the allocation control unit 322 determines the amount of traffic (amount of allocated data) to be allocated to the transmitting terminal and the cooperative terminal according to terminal status information or radio status information obtained from each of the transmitting terminal and the cooperative terminal.

[0093] 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 information indicating the allocated data amount to the transmitting terminal and the candidate terminals.

[0094] 6 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.

[0095] 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 wireless state information acquisition unit 241, a terminal information acquisition unit 242, and a communication control unit 244 by the one or more processors executing programs.

[0096] The communication control unit 244 controls the communication between the RAN communication unit 21 and the PAN communication unit 22. The communication control unit 244 controls the PAN communication unit 22 to transmit the terminal state information and the radio state information to the server 30.

[0097] (Example of operation in the second embodiment) Next, the flow of processing in the wireless communication system 100a in the second embodiment 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, the case where the server 30 is the master terminal will be described as an example.

[0098] Assume that data to be transmitted is generated in the terminal device 20a-1. The communication control unit 244-1 of the terminal device 20a-1 controls the RAN communication unit 21-1 to transmit a connection request to the base station device 10. The RAN communication unit 21-1 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 244-1.

[0099] The base station device 10 receives a connection request transmitted from the terminal device 20a-1. The base station device 10 transmits a reference signal to the terminal device 20a-1 in response to the received connection request. The RAN communication unit 21-1 of the terminal device 20a-1 receives the reference signal transmitted from the base station device 10. As a result, the terminal device 20a-1 and the base station device 10 are connected. The radio state information acquisition unit 241-1 of the terminal device 20a-1 acquires radio state information based on the received reference signal.

[0100] The communication control unit 244-1 controls the PAN communication unit 22-1 to transmit the wireless state information acquired by the wireless state information acquisition unit 241-1 to the server 30, which is the master terminal. The PAN communication unit 22-1 transmits the wireless state information to the server 30 in accordance with the control of the communication control unit 244-1. The communication unit 31 of the server 30 receives the wireless state information transmitted from the terminal device 20a-1 and stores the received wireless state information in a memory (not shown).

[0101] Furthermore, the communication control unit 244-1 of the terminal device 20a-1 controls the PAN communication unit 22-1 to notify the server 30 that data to be transmitted has been generated. The communication unit 31 of the server 30 receives the notification from the terminal device 20a-1. In response to receiving the notification, the communication control unit 323 of the server 30 controls the communication unit 31 to cause each terminal device 20a belonging to the same group to transmit a request signal for sharing wireless state information. The communication unit 31 transmits the request signal to each terminal device 20a-1 and 20a-3 belonging to the same group in accordance with the control of the communication control unit 323.

[0102] The PAN communication unit 22-2 of the terminal device 20a-2 receives the request signal transmitted from the server 30. In response to receiving the request signal, the communication control unit 244-2 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 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 244-2.

[0103] 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.

[0104] The communication control unit 244-2 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, which is the master terminal. 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 244-2. The communication unit 31 of the server 30 receives the wireless state information transmitted from the terminal device 20a-2 and stores the received wireless state information in a memory (not shown).

[0105] The PAN communication unit 22-3 of the terminal device 20a-3 receives the request signal transmitted from the server 30. In response to receiving the request signal, the communication control unit 244-3 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 transmits the connection request to the base station device 10 in accordance with the control of the communication control unit 244-3.

[0106] 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. The RAN communication unit 21-3 of the terminal device 20a-3 receives the reference signal transmitted from the base station device 10. As a result, the terminal device 20a-3 and the base station device 10 are connected. The radio state information acquisition unit 241-3 of the terminal device 20a-3 acquires radio state information based on the received reference signal.

[0107] The communication control unit 244-3 controls the PAN communication unit 22-3 to transmit the wireless state information acquired by the wireless state information acquisition unit 241-3 to the server 30, which is the master terminal. The PAN communication unit 22-3 transmits the wireless state information to the server 30 in accordance with the control of the communication control unit 244-3. The communication unit 31 of the server 30 receives the wireless state information transmitted from the terminal device 20a-3 and stores the received wireless state information in a memory (not shown).

[0108] The cooperative terminal determiner 321 of the server 30 determines a cooperative terminal based on wireless state information stored in a memory (not shown). Here, it is assumed that the cooperative terminal determiner 321 determines the terminal device 20a-2 as a cooperative terminal.

[0109] The cooperative terminal determiner 321 notifies the communication controller 323 that the terminal device 20a-2 has been determined to be a cooperative terminal. The communication controller 323 generates a determination notification addressed to the terminal device 20a-2 in response to the notification from the cooperative terminal determiner 321. For example, the communication controller 323 generates a determination notification that includes an instruction to operate the terminal device as a cooperative terminal.

[0110] The communication control unit 323 controls the communication unit 31 to transmit the determination notification generated by the communication control unit 323 to the terminal device 20a-2. The communication unit 31 transmits the determination notification to the terminal device 20a-2 in accordance with the control of the communication control unit 323. The PAN communication unit 22-2 of the terminal device 20a-2 receives the determination notification transmitted from the server 30. 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.

[0111] The server 30 may transmit a decision notification to the terminal device 20 a-3 that was not determined as a cooperative terminal, including a notification that the terminal device 20 a-3 will not operate as a cooperative terminal. The terminal device 20 a-3 stops operating in response to the decision notification transmitted from the server 30.

[0112] Next, the allocation control unit 322 of the server 30 determines an allocation destination and an amount of allocated data. The allocation control unit 322 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 322 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.

[0113] 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 244-1 divides the transmission data in accordance with the received information indicating the amount of allocated data. The communication control unit 244-1 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. The PAN communication unit 22-1 transmits the divided data to the terminal device 20a-2 in accordance with the control of the communication control unit 244-1.

[0114] 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 244-2.

[0115] 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 244-1. This allows the base station device 10 to receive the divided data transmitted from the transmitting terminal and each of the cooperative terminals.

[0116] In the above process, the server 30, which is the master terminal, determines the cooperative terminals using the wireless state information of each terminal device 20a, but the master terminal may also determine the cooperative terminals using the terminal state information of each terminal device 20a. When using terminal state information, the terminal devices 20a other than the master terminal (terminal devices 20a-1 to 20a-3) acquire the terminal state information and share it with the master terminal when they receive a request for terminal state information from the master terminal.

[0117] The above process shows a configuration in which terminal devices 20a other than the master terminal (for example, terminal devices 20a-2 and 20a-3) acquire wireless state information by wirelessly communicating with the base station device 10 in response to a request for wireless state information from the master terminal. The terminal devices 20a other than the master terminal (terminal devices 20a-2 and 20a-3) may acquire and store wireless state information by periodically performing wireless communication with the base station device 10, and may share the stored wireless state information with the master terminal in response to a request for wireless state information from the master terminal.

[0118] The wireless communication system 100a configured as above can achieve the same effects as those of the first embodiment.

[0119] 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.

[0120] (Variation of the Second Embodiment) In the above-described configuration, 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 receives, via the base station device 10, radio state information and terminal state information of each candidate terminal used to determine a cooperative terminal. Each terminal device 20a may individually transmit its radio state information and terminal state information to the server 30 via the base station device 10, or one terminal device 20a may aggregate the radio state information and terminal state information of all terminal devices 20a (including its own device) in the group and transmit the aggregated information to the server 30 via the base station device 10. Furthermore, the server 30 transmits information such as a determination notification, an allocation destination, and an allocated data amount to the target terminal device 20a via the base station device 10. The operation performed by the server 30 is the same as that shown in the second embodiment, except that communication with each terminal device 20 a is performed via the base station device 10 .

[0121] (Modifications common to the first and second embodiments)

[0122] In each of the above-described embodiments, a configuration has been shown in which the master terminal transmits a request signal to each terminal device 20, 20a in the group, and each terminal device 20, 20a connects to the base station device 10 in response to receiving the request signal, acquires radio state information, and then shares the radio state information with the master terminal. In contrast, each terminal device 20, 20a may connect to the base station device 10 and acquire radio state information, and then share the radio state information with the master terminal, when it becomes possible to select a better cooperative terminal, such as when the holding state of the own device changes (for example, when the position or orientation changes), when a new cooperative terminal is added, or when a new candidate terminal is added to the group.

[0123] 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.

[0124] 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).

[0125] 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.

[0126] The present invention is applicable to wireless access networks.

[0127] 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... Cooperative terminal determination unit, 244, 323... Communication control unit, 245, 322... Allocation control unit

Claims

1. A wireless communication system comprising a plurality of wireless communication devices and a base station device, wherein one of the plurality of wireless communication devices comprises a cooperative terminal determination unit that calculates a correlation value between the device itself and other wireless communication devices using either wireless status information, which is information relating to the quality of wireless communication of each wireless communication device, or terminal status information, which is information relating to the status of each wireless communication device, and determines one or more cooperative terminals to execute cooperative operation based on the calculated correlation value.

2. The wireless communication system according to claim 1, wherein the cooperative terminal determination unit determines the wireless communication device with the lowest correlation value as the one or more cooperative terminals.

3. The wireless communication system according to claim 1 or 2, wherein the cooperative terminal determination unit calculates the correlation value using different information between the wireless state information of the own device and the wireless state information of the other wireless communication device.

4. The wireless communication system described in claim 1 or 2, wherein the cooperative terminal determination unit calculates a correlation value between the wireless state information or the terminal state information of the one or more cooperative terminals and the wireless state information or the terminal state information of a wireless communication device among the plurality of wireless communication devices that is not a cooperative terminal, and if the calculated correlation value is equal to or less than a threshold, adds the wireless communication device that is not a cooperative terminal to the cooperative terminals.

5. The wireless communication system according to claim 1 or 2, wherein, when there are multiple cooperative terminals, the cooperative terminal determination unit calculates a correlation value using either the wireless state information or the terminal state information of each of the multiple cooperative terminals, and, if the calculated correlation value is equal to or greater than a threshold, excludes the cooperative terminal whose correlation value is equal to or greater than the threshold from the cooperative terminals.

6. The wireless communication system according to claim 1 or 2, wherein the plurality of wireless communication devices share the wireless state information or the terminal state information with the wireless communication device equipped with the cooperative terminal determination unit directly or via the base station device.

7. A wireless communication system according to claim 1 or 2, wherein the plurality of wireless communication devices include a plurality of wireless terminals and one or more servers, and the cooperative terminal determination unit is provided in at least one wireless terminal of the plurality of wireless terminals or in the one or more servers.

8. A cooperative terminal determination method performed by a wireless communication system comprising a plurality of wireless communication devices and a base station device, in which one of the plurality of wireless communication devices calculates a correlation value between itself and other wireless communication devices using either wireless state information, which is information about the quality of wireless communication of each wireless communication device, or terminal state information, which is information about the state of each wireless communication device, and determines one or more cooperative terminals to perform cooperative operation based on the calculated correlation value.

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