Wireless communication device and wireless communication method

Abstract

To form a group without using a base station.SOLUTION: A wireless communication device comprises: a reception unit which receives, on a first channel, a group creation request signal from a management device and a group subscription request signal from each of a plurality of reader devices; a mode setting unit which, when the group creation request signal is received, sets the device to a group creation mode for a first predetermined time; a storage unit which receives the group subscription request signal from each of the plurality of reader devices during a group creation mode and stores radio wave intensity at which the group subscription request signal was received in association with an identifier of a reader device that has transmitted the group subscription request signal; a selection unit which, when the group creation mode ends, selects a reader device of which the radio wave intensity stored in the storage device is a maximum value; and a transmission unit which transmits, to the reader device selected by the selection unit, a group subscription application signal on a second channel that is different from the first channel.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a wireless communication device and a wireless communication method. [Background technology]

[0002] There is a known technology in which a base station forms a group to enable group communication. Patent Document 1 discloses a technology in which a group is formed by transmitting a group number to a wireless device via a base station depending on the situation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-265958 Summary of the Invention [Problem to be solved by the invention]

[0004] Typically, groups are formed by a base station, so wireless communication devices cannot dynamically form groups themselves according to the activity status of the group, and it is not possible to form groups that reflect the intentions of users who own wireless communication devices.

[0005] An object of the present invention is to provide a wireless communication device and a wireless communication method that can form a group without going through a base station. [Means for solving the problem]

[0006] A wireless communication device according to the present invention comprises a receiving unit that receives a group creation request signal from a management device and a group joining request signal from each of a plurality of leader devices on a first channel; a mode setting unit that sets the device into a group creation mode for a predetermined first time period when the group creation request signal is received; a memory unit that receives a group joining request signal from each of the plurality of leader devices during the group creation mode period and associates and stores the radio wave strength at the time the group joining request signal was received with the identifier of the leader device that transmitted the group joining request signal; a selection unit that selects the leader device whose radio wave strength stored in the memory unit is at the maximum value when the group creation mode period ends; and a transmission unit that transmits a group joining application signal to the leader device selected by the selection unit on a second channel different from the first channel.

[0007] A wireless communication method according to the present invention includes the steps of receiving a group creation request signal from a management device and a group join request signal from each of a plurality of leader devices on a first channel; setting the device into a group creation mode for a predetermined first time period when the group creation request signal is received; receiving a group join request signal from each of the plurality of leader devices during the group creation mode period, and correlating the radio wave strength at the time the group join request signal was received with the identifier of the leader device that transmitted the group join request signal and storing them in a memory unit; selecting the leader device whose radio wave strength stored in the memory unit is at the maximum value when the group creation mode period ends; and transmitting a group join application signal to the selected leader device on a second channel different from the first channel. [Effects of the Invention]

[0008] According to the present invention, a group can be formed without going through a base station. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a diagram illustrating an example of the configuration of a wireless communication system according to an embodiment. [Figure 2] FIG. 2 is a block diagram illustrating an example of the configuration of a management device according to the embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of a device list according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of a channel list according to the embodiment. [Figure 5] FIG. 5 is a block diagram illustrating an example of the configuration of a reader device according to the embodiment. [Figure 6] FIG. 6 is a block diagram illustrating an example of the configuration of a wireless communication device according to the embodiment. [Figure 7] FIG. 7 is a sequence diagram showing the flow of a group formation process in the wireless communication system according to the embodiment. [Figure 8] FIG. 8 is a diagram showing an example of a display screen of the reader device according to the embodiment. [Figure 9A] FIG. 9A is a diagram illustrating an example of a display screen of a management device according to an embodiment. [Figure 9B] FIG. 9B is a diagram illustrating an example of a display screen of the management device according to the embodiment. [Figure 10] FIG. 10 is a diagram illustrating an example of a display screen of the management device according to the embodiment. [Figure 11] FIG. 11 is a sequence diagram showing the flow of a group formation process in the wireless communication system according to the embodiment. [Figure 12] FIG. 12 is a sequence diagram showing the flow of a group formation process in the wireless communication system according to the embodiment. [Figure 13] FIG. 13 is a sequence diagram showing the flow of a group formation process in the wireless communication system according to the embodiment. [Figure 14] FIG. 14 is a diagram illustrating an example of a display screen of a general device according to the embodiment. [Figure 15] FIG. 15 is a sequence diagram showing the flow of a group formation process in the wireless communication system according to the embodiment. [Figure 16]FIG. 16 is a sequence diagram showing the flow of a group formation process in the wireless communication system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to this embodiment, and in the following embodiments, the same components are designated by the same reference numerals, and redundant explanations will be omitted.

[0011] [Embodiment] [Wireless communication system] An example of the configuration of a wireless communication system according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of a wireless communication system according to an embodiment.

[0012] 1, the wireless communication system 1 includes a management device 10, leader devices 20-1 to 20-8, and general devices 30-1 to 30-n (n is an integer equal to or greater than 2). The leader devices 20-1 to 20-8 may be collectively referred to as leader devices 20. The general devices 30-1 to 30-n may be collectively referred to as general devices 30. The wireless communication system 1 may include, for example, a base station device (not shown) that relays wireless communication.

[0013] In this embodiment, the wireless communication system 1 is a system used, for example, at event venues for various indoor and outdoor events. The wireless communication system 1 is configured so that a general device 30 performs group communication with other general devices 30 including a leader device 20.

[0014] The management device 10 manages the wireless communication system 1. For example, the management device 10 manages group communication of a plurality of general devices 30 in the wireless communication system 1. The wireless communication system 1 includes only one management device 10. The management device 10 is, for example, a business wireless communication device.

[0015] The leader device 20 manages the general devices 30. The leader devices 20 form groups for the general devices 30 to perform group communication. In the example shown in FIG. 1 , the wireless communication system 1 includes eight leader devices 20. In the following description, the number of leader devices 20 is assumed to be eight, but the present invention is not limited to this. The number of leader devices 20 may be eight or more, or may be fewer than eight. The leader device 20 is, for example, a business wireless communication device. The leader device 20 may be carried by a user or may be fixed at a predetermined location. If the leader device 20 is fixed at a predetermined location, it may be arranged so as to cover the communication area of ​​the wireless communication system 1.

[0016] A general device 30 performs group communication with other general devices 30. A general device 30 belongs to a group formed by one of a plurality of leader devices 20. A general device 30, including the leader device 20, performs group communication or individual communication with other general devices 30 in the same group. A general device 30 is also called a general device. A general device 30 is, for example, a business wireless communication device.

[0017] [Configuration of management device] An example of the configuration of a management device according to an embodiment will be described with reference to Fig. 2. Fig. 2 is a block diagram showing an example of the configuration of a management device according to an embodiment.

[0018] As shown in FIG. 2, the management device 10 includes a transmitter 40, a receiver 42, an input unit 44, a display unit 46, an audio output unit 48, a memory unit 50, a GNSS (Global Navigation Satellite System) receiver 52, and a control unit 54.

[0019] The transmitting unit 40 transmits audio signals and various information to an external device. For example, the transmitting unit 40 transmits audio signals and various information to the reader device 20 and the general device 30. Details of the transmitting unit 40 will be described later.

[0020] The receiving unit 42 receives audio signals and various information from an external device. For example, the receiving unit 42 receives audio signals and various information from the leader device 20 and the general device 30. The receiving unit 42 will be described in detail later.

[0021] The input unit 44 accepts various input operations for the management device 10. The input unit 44 outputs an input signal corresponding to the accepted input operation to the control unit 54. The input unit 44 includes, for example, a touch panel, a button, a switch, a microphone, etc. The input unit 44 includes, for example, a PTT (Push to Talk) button for starting a call. When a touch panel is used as the input unit 44, the input unit 44 is disposed on the display unit 46.

[0022] The display unit 46 displays various images. The display unit 46 is, for example, a display including a liquid crystal display (LCD) or an organic electroluminescence (EL) display.

[0023] The audio output unit 48 is a speaker that outputs various types of audio.

[0024] The storage unit 50 stores various types of information. The storage unit 50 stores information such as the contents of calculations performed by the control unit 54 and programs. The storage unit 50 stores, for example, a device list for uniquely identifying each of the reader devices 20 and the general devices 30 included in the wireless communication system 1. The storage unit 50 stores, for example, a channel list that associates the reader devices 20 with channels used by the reader devices 20. The storage unit 50 includes, for example, at least one of a random access memory (RAM), a main storage device such as a read only memory (ROM), and an external storage device such as a hard disk drive (HDD).

[0025] 3 is a diagram showing an example of a device list according to the embodiment. As shown in FIG. 3, the device list 50a includes items such as "wireless communication device" and "identifier."

[0026] The term "wireless communication device" refers to a wireless communication device included in the wireless communication system 1 managed by the management device 10. The term "identifier" refers to an ID for uniquely identifying a wireless communication device included in the wireless communication system 1 managed by the management device 10.

[0027] In the example shown in Fig. 3, for example, the identifier of the "management device 10" is "UID1". Also, for example, the identifier of the "leader device 20-1" is "UID2". Also, for example, the identifier of the "general device 30-1" is "UID10".

[0028] Fig. 4 is a diagram showing an example of a channel list according to the embodiment. As shown in Fig. 4, a channel list 50b includes items such as "Channel No." and "Use."

[0029] "Channel No." indicates the channel used in communication. "Use" indicates the use of the corresponding channel. The channel specifies, for example, the frequency or thread used in communication. For example, if the wireless communication system 1 includes a base station device (not shown), the channel is a relay channel managed by the base station device.

[0030] In the example shown in Fig. 4, for example, the use of "CH1" is "normal use, message transmission." For example, the use of "CH2" is "used by leader device 20-1." For example, the use of "CH9" is "used by leader device 20-8."

[0031] The GNSS receiving unit 52 is configured with a GNSS receiver that receives GNSS signals from GNSS satellites, etc. The GNSS receiving unit 52 outputs the received GNSS signals to a position information acquiring unit 62 of the control unit .

[0032] The control unit 54 controls each unit of the management device 10. The control unit 54 has, for example, an information processing device such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit), and a storage device such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The control unit 54 executes a program that controls the operation of the management device 10 according to the present invention. The control unit 54 may be realized by an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array). The control unit 54 may be realized by a combination of hardware and software.

[0033] The control unit 54 includes a communication control unit 60 , a location information acquisition unit 62 , a message generation unit 64 , and a display control unit 66 .

[0034] The communication control unit 60 controls the transmitting unit 40 and the receiving unit 42. The communication control unit 60 controls the transmitting unit 40 to transmit various types of information to the reader device 20 and the general device 30. The communication control unit 60 controls the receiving unit 42 to receive various types of information from the reader device 20 and the general device 30.

[0035] The position information acquisition unit 62 acquires current position information indicating the current position of the management device 10. The position information acquisition unit 62 acquires the current position information of the management device 10 based on the GNSS signal received by the GNSS receiver 52.

[0036] The message generator 64 generates a group request creation message for causing the leader device 20 to form a group of general devices 30. The message generator 64 will be described in detail later.

[0037] The display control unit 66 controls the display unit 46 to display various types of information. Details of the display control unit 66 will be described later.

[0038] [Reader device configuration] An example of the configuration of a reader device according to the embodiment will be described with reference to Fig. 5. Fig. 5 is a block diagram showing an example of the configuration of a reader device according to the embodiment.

[0039] As shown in FIG. 5, the reader device 20 includes a transmitter 70, a receiver 72, an input unit 74, a display unit 76, an audio output unit 78, a memory unit 80, a GNSS receiver 82, and a control unit 84.

[0040] The transmitting unit 70 transmits audio signals and various information to external devices. For example, the transmitting unit 70 transmits audio signals and various information to the management device 10 and the general device 30. Details of the transmitting unit 70 will be described later.

[0041] The receiving unit 72 receives audio signals and various information from external devices. For example, the receiving unit 72 receives audio signals and various information from the management device 10 and the general device 30. The receiving unit 72 will be described in detail later.

[0042] The input unit 74 accepts various input operations for the reader device 20. The input unit 74 outputs an input signal corresponding to the accepted input operation to the control unit 84. The input unit 74 includes, for example, a touch panel, a button, a switch, a microphone, etc. The input unit 74 includes, for example, a PTT button for starting a call. When a touch panel is used as the input unit 74, the input unit 74 is disposed on the display unit 76.

[0043] The display unit 76 displays various images and is, for example, a display including a liquid crystal display, an organic EL display, or the like.

[0044] The audio output unit 78 is a speaker that outputs various types of audio.

[0045] The storage unit 80 stores various types of information. The storage unit 80 stores information such as the contents of calculations performed by the control unit 84 and programs. For example, the storage unit 80 stores a received signal strength indicator (RSSI) value, which is the radio wave strength of a channel when a signal is received from a general device 30 belonging to the group of the leader device 20. The storage unit 80 includes, for example, at least one of a RAM, a main storage device such as a ROM, and an external storage device such as an HDD.

[0046] The GNSS receiving unit 82 is configured with a GNSS receiver that receives GNSS signals from GNSS satellites, etc. The GNSS receiving unit 82 outputs the received GNSS signals to a position information acquiring unit 92 of the control unit 84.

[0047] The control unit 84 controls each unit of the reader device 20. The control unit 84 has, for example, an information processing device such as a CPU or an MPU, and a storage device such as a RAM or a ROM. The control unit 84 executes a program that controls the operation of the reader device 20 according to the present invention. The control unit 84 may be realized by, for example, an integrated circuit such as an ASIC or an FPGA. The control unit 84 may also be realized by a combination of hardware and software.

[0048] The control unit 84 includes a communication control unit 90 , a location information acquisition unit 92 , a message generation unit 94 , a timer unit 96 , and a display control unit 98 .

[0049] The communication control unit 90 controls the transmitting unit 70 and the receiving unit 72. The communication control unit 90 controls the transmitting unit 70 to transmit various types of information to the management device 10 and the general device 30. The communication control unit 90 controls the receiving unit 72 to receive various types of information from the management device 10 and the general device 30.

[0050] The position information acquisition unit 92 acquires current position information indicating the current position of the reader device 20. The position information acquisition unit 92 acquires the current position information of the reader device 20 based on the GNSS signal received by the GNSS receiver 82.

[0051] The message generator 94 generates a group join request message to form a group when it receives a group creation request message from the management device 10. The message generator 94 will be described in detail later.

[0052] The timer unit 96 measures the time. The timer unit 96 measures the time required to accept a request to join the group from a general device 30. Details of the timer unit 96 will be described later.

[0053] The display control unit 98 controls the display unit 76 to display various types of information. Details of the display control unit 98 will be described later.

[0054] [General equipment configuration] An example of the configuration of a general device according to the embodiment will be described with reference to Fig. 6. Fig. 6 is a block diagram showing an example of the configuration of a general device according to the embodiment.

[0055] As shown in FIG. 6, the general device 30 includes a transmitting unit 100, a receiving unit 102, an input unit 104, a display unit 106, an audio output unit 108, a memory unit 110, a GNSS receiving unit 112, and a control unit 114.

[0056] The transmitting unit 100 transmits audio signals and various information to an external device. For example, the transmitting unit 100 transmits audio signals and various information to the management device 10 and the reader device 20. Details of the transmitting unit 100 will be described later.

[0057] The receiving unit 102 receives audio signals and various information from external devices. For example, the receiving unit 102 receives audio signals and various information from the management device 10 and the leader device 20. Details of the receiving unit 102 will be described later.

[0058] The input unit 104 accepts various input operations for the general device 30. The input unit 104 outputs an input signal corresponding to the accepted input operation to the control unit 114. The input unit 104 includes, for example, a touch panel, a button, a switch, a microphone, etc. The input unit 104 includes, for example, a PTT button for starting a call. When a touch panel is used as the input unit 104, the input unit 104 is arranged on the display unit 106.

[0059] The display unit 106 displays various images. The display unit 106 is, for example, a display including a liquid crystal display, an organic EL display, or the like.

[0060] The audio output unit 78 is a speaker that outputs various types of audio.

[0061] The storage unit 110 stores various types of information. The storage unit 110 stores information such as the contents of calculations performed by the control unit 114 and programs. The storage unit 110 stores, for example, an RSSI value, which is the radio wave intensity of a channel when a signal is received from the reader device 20. The storage unit 110 includes, for example, at least one of a RAM, a main storage device such as a ROM, and an external storage device such as an HDD.

[0062] The GNSS receiving unit 112 is configured with a GNSS receiver that receives GNSS signals from GNSS satellites, etc. The GNSS receiving unit 112 outputs the received GNSS signals to a position information acquiring unit 122 in the control unit 114.

[0063] The control unit 114 controls each unit of the general device 30. The control unit 114 has, for example, an information processing device such as a CPU or an MPU, and a storage device such as a RAM or a ROM. The control unit 114 executes a program that controls the operation of the general device 30 according to the present invention. The control unit 114 may be realized by, for example, an integrated circuit such as an ASIC or an FPGA. The control unit 114 may also be realized by a combination of hardware and software.

[0064] The control unit 114 includes a communication control unit 120 , a location information acquisition unit 122 , a message generation unit 124 , a timer unit 126 , a mode setting unit 128 , a selection unit 130 , and a display control unit 132 .

[0065] The communication control unit 120 controls the transmitting unit 100 and the receiving unit 102. The communication control unit 120 controls the transmitting unit 100 to transmit various types of information to the management device 10 and the reader device 20. The communication control unit 120 controls the receiving unit 102 to receive various types of information from the management device 10 and the reader device 20.

[0066] The position information acquisition unit 122 acquires current position information indicating the current position of the general device 30. The position information acquisition unit 122 acquires the current position information of the general device 30 based on the GNSS signal received by the GNSS receiving unit 112.

[0067] The message generator 124 generates a group join application message for joining a group when it receives group join request messages from a plurality of leader devices 20. Details of the message generator 124 will be described later.

[0068] The timer unit 126 measures time. The timer unit 126 measures the time limit for applying to join a group to the leader device 20. The timer unit 126 will be described in detail later.

[0069] The mode setting unit 128 sets the mode of the general device 30. When the mode setting unit 128 receives a group creation request signal, the mode setting unit 128 sets the general device 30 to a group creation mode for a predetermined first time period. Details of the mode setting unit 128 will be described later.

[0070] The selection unit 130 determines the radio wave intensity of each of the plurality of reader devices 20. The selection unit 130 selects the reader device with the greatest radio wave intensity from the plurality of reader devices 20. Details of the selection unit 130 will be described later.

[0071] The display control unit 132 controls the display unit 106 to display various types of information. Details of the display control unit 132 will be described later.

[0072] [Group formation process] (Reader device processing) A group formation process of the wireless communication system according to the embodiment will be described with reference to Fig. 7. Fig. 7 is a sequence diagram showing the flow of a group formation process of the wireless communication system according to the embodiment.

[0073] 7 mainly shows the process executed by the leader device 20 when forming a group, and the process when permitting a general device 30 to join the group.

[0074] Normally, before a group is formed, the channel to be used by the management device 10, the leader device 20, and the general device 30 is set to CH1 in the channel list shown in Fig. 4. CH1 is a type of first channel in this embodiment.

[0075] The message generator 64 of the management device 10 generates a group creation request message for creating a group for group communication (step S10). Specifically, the message generator 64 generates the group creation request message in accordance with operation information input by the administrator to the input unit 44. The group creation request message is also called a group creation request signal. Then, the process proceeds to step S12.

[0076] The transmitter 40 of the management device 10 transmits a group creation request message to the leader device 20 under the control of the communication control unit 60 (step S12). Specifically, the transmitter 40 transmits the group creation request message to the leader device 20 over CH1 under the control of the communication control unit 60. Then, the process proceeds to step S14.

[0077] The communication control unit 60 of the management device 10 starts scanning each channel in the wireless communication system 1 (step S14). Specifically, the communication control unit 60 performs scanning on CH2 to CH9 used by each of the multiple leader devices 20 included in the wireless communication system 1. The communication control unit 60 performs scanning at all times until it receives group creation completion messages from all leader devices 20 in the wireless communication system 1. Scanning is a state in which the management device 10 waits for group creation completion messages and group update messages from the leader devices 20. Then, the process proceeds to step S16.

[0078] The receiving unit 72 of the leader device 20 receives the group creation request message from the management device 10 under the control of the communication control unit 90 (step S16), and then the process proceeds to step S18.

[0079] The timer unit 96 of the leader device 20 starts a group creation timer that specifies the time limit for creating a group (step S18). At the same time, a group creation processing timer is also started in the timer unit 126 of the general device 30, which will be described later in the general device processing. There is no particular limit on the time limit, but the timer unit 96 may set it according to the number of general devices 30 that are the target of the group. For example, the timer unit 96 may set a longer time limit if there are a large number of general devices 30, and a shorter time limit if there are a small number of general devices 30. Then, the process proceeds to step S20.

[0080] The message generator 94 of the leader device 20 generates a group join request message requesting the general device 30 to join the group (step S20). The group join request message is also called a group join request signal. Then, the process proceeds to step S22.

[0081] The transmitting unit 70 of the leader device 20 transmits a group join request message to the general device 30 under the control of the communication control unit 90 (step S22). Specifically, the transmitting unit 70 of each leader device 20 transmits the group join request message to the general device 30 on the channel CH1 under the control of the communication control unit 90. After transmitting the group join request message, the communication control unit 90 of the leader device 20 switches to its own set channel and waits for a group join application message, which is a response from the general device 30. For example, if the leader device 20 is the leader device 20-1, the communication control unit 90 of the leader device 20-1 switches the channel from CH1 to CH2 and receives the group join request message from the general device 30 on CH2. Here, CH2 is a type of second channel in this embodiment. The group join request message will be described later. Each leader device 20 included in the wireless communication system 1 avoids collision with group join request messages transmitted by other leader devices 20 on CH1, for example, by executing a random access procedure with the management device 10. Then, proceed to step S24.

[0082] The receiving unit 102 of the general device 30 receives the group join request message under the control of the communication control unit 120 (step S24), and then the process proceeds to step S26.

[0083] When group join request messages are received from a plurality of leader devices 20, the selection unit 130 of the general device 30 selects a leader device 20 to join the group. The selection of the leader device 20 by the selection unit 130 of the general device 30 will be described later in the processing of the general device 30. The message generation unit 124 of the general device 30 generates a group join request message indicating a request to the selected leader device 20 to join the group (step S26). The group join request message is also called a group join request signal. Then, the process proceeds to step S28.

[0084] The transmitting unit 100 of the general device 30, under the control of the communication control unit 120, switches to the channel set in the leader device 20 of the group to join, and transmits a group join request message to the leader device 20 (step S28). Then, the process proceeds to step S30.

[0085] The receiving unit 72 of the leader device 20 receives the group join request message from the general device 30 under the control of the communication control unit 90 (step S30), and then the process proceeds to step S32.

[0086] When the leader device 20 accommodates a new general device 30, the control unit 84 updates the accommodation number (step S32). The accommodation number refers to the number of general devices 30 that can be registered in the leader device 20. The accommodation number also refers to the number of general devices 30 that can join the group of the leader device 20. The control unit 84 accommodates the new general device 30 when the current accommodation number is equal to or less than the maximum number that can be accommodated. Specifically, the control unit 84 updates the accommodation number by incrementing the current accommodation number N by +1 (N+1). Then, the process proceeds to step S34.

[0087] The control unit 84 stores the ID and RSSI value of the general device 30 in the storage unit 80 (step S34). Specifically, the control unit 84 associates the ID, which is the identifier of the general device 30 that transmitted the group joining request message, with the RSSI value at the time of receiving the group joining request message and stores them in the storage unit 80. Specifically, if the ID of the general device 30 is "UID11" and the RSSI value is "-100 dBm," the control unit 84 associates "UID11" with "-100 dBm" and stores them in the storage unit 80. Then, the process proceeds to step S36.

[0088] The message generator 94 of the leader device 20 generates a group joining permission / denial message (step S36). Specifically, the message generator 94 generates a group joining permission / denial message (OK) indicating that joining to the group is permitted. The group joining permission / denial message is also called a group joining permission / denial signal. Then, the process proceeds to step S38.

[0089] The transmitter 70 of the leader device 20 transmits a group joining permission / denial message (OK) to the general device 30 on the channel set for itself under the control of the communication control unit 90 (step S38), and then proceeds to step S40.

[0090] The timer unit 96 of the leader device 20 waits for the time limit to elapse and ends the group creation timer (step S40). Until the group creation timer ends, the timer unit 96 waits for a group join request message from the general device 30, and if a group join request message is received, the process repeats steps S30 to S38. Then, the process proceeds to step S42.

[0091] The message generation unit 94 of the leader device 20 generates a group creation completion message indicating that the formation of the group has been completed (step S42). The group creation completion message includes the ID and RSSI value of the newly joined general device 30. The group creation completion message includes the current location information of the leader device 20 acquired by the location information acquisition unit 92 of the leader device 20. The group creation completion message is also called a group creation completion signal. Then, the process proceeds to step S44.

[0092] The transmitter 70 of the leader device 20, under the control of the communication control unit 90, switches the channel to CH1 and transmits a group creation completion message to the management device 10 (step S44).

[0093] The display control unit 98 of the leader device 20 displays the ID and RSSI value of the general device 30 that has newly joined the group (step S46). Fig. 8 is a diagram showing an example of a display screen of the leader device according to the embodiment.

[0094] 8, the display screen 200 shows general devices 30 accommodated in a specific leader device 20. The display screen 200 shows an icon 210, a UID, and an RSSI value of the general device 30 accommodated in the specific leader device 20. The newly added general device 30 is shown to have an ID of "UID12" and an RSSI value of "-98 dBm."

[0095] On the display screen 200, when the user selects, for example, "UID12" and presses the Call image button 220 or the PTT button, the leader device 20 makes a voice call to the general device 30 of "UID12" on the channel set in the leader device 20.

[0096] Returning to Fig. 7, the timer unit 96 of the leader device 20 starts the operation timer (step S48). The operation timer is a timer used to update the RSSI value of the general device 30 accommodated in the leader device 20. The process of updating the RSSI value will be described later.

[0097] 7, the management device 10 receives a group creation completion message from the leader device 20, and can display the position of the leader device 20 and the general devices 30 included in the group on the display unit 76. Figures 9A and 9B are diagrams showing examples of the display screen of the management device according to the embodiment.

[0098] 9A and 9B, the display screen 300 shows the number of general devices 30 accommodated in each leader device 20. The display screen 300 includes a number-of-people display icon 310, a Next image button 320, and a Clear image button 330.

[0099] The number of people display icon 310 indicates the number of general devices 30 contained in the corresponding leader device 20. For example, it is shown that the leader device 20 with the ID "UID2" contains 10 general devices 30. "Ungrouped" shown in Fig. 9B indicates the number of general devices 30 that are not members of any group.

[0100] On the display screen 300, when the user selects, for example, "UID2" and presses the Next image button 320, details of the general device 30 contained in "UID2" are displayed. The Clear image button 330 is a button used to disband a group. The administrator using the management device 10 can disband a group by pressing the Clear image button 330 at any time when it is no longer necessary to form the group.

[0101] Fig. 10 is a diagram showing an example of a display screen of a management device according to an embodiment. Fig. 10 is a diagram showing details of a general device 30 contained in a leader device 20 with an ID of "UID2". As shown in Fig. 10, a display screen 400 includes a leader icon 410 indicating the leader device 20, a general icon 420 indicating the general device 30, a Call image button 430, and a Back image button 440.

[0102] As shown in FIG. 10, when "UID2" is selected in FIG. 9A, a leader icon 410 and "UID2," which is the ID of the corresponding leader device 20, are displayed on the display screen 400. For example, an exclamation mark is added to the leader icon 410. A general icon 420 and "UID12," which is the ID of the corresponding general device 30, are displayed on the display screen 400. Note that when "Ungrouped" is selected in FIG. 9B, a general icon 420 indicating a general device 30 that could not join a group and the ID of the corresponding general device 30 are displayed on the display screen 400.

[0103] On the display screen 400, when the user selects, for example, "UID12" and presses the Call image button 430 or the PTT button, the management device 10 makes a voice call to the general device 30 with "UID12" on CH2, which is the channel set for the leader device 20-1 with "UID2."

[0104] (Reader device processing) The group formation process of the wireless communication system according to the embodiment will be described with reference to Fig. 11. Fig. 11 is a sequence diagram showing the flow of the group formation process of the wireless communication system according to the embodiment.

[0105] Fig. 11 mainly shows the process executed by the leader device 20 when forming a group, and Fig. 11 shows the process when refusing to allow a general device 30 to join the group.

[0106] The processes from step S60 to step S84 are the same as the processes from step S10 to step S34 shown in FIG. 7, respectively, and therefore will not be described here.

[0107] The message generator 94 of the leader device 20 generates a group joining permission / denial message (step S86). Specifically, the message generator 94 generates a group joining permission / denial message (NG) indicating that joining the group is denied because the current capacity has reached the maximum. Then, the process proceeds to step S88.

[0108] The transmitter 70 of the leader device 20, under the control of the communication control unit 90, transmits a group joining permission / refusal message (NG) to the general device 30 on the channel set for itself (step S88).

[0109] The processes from step S90 to step S98 are the same as the processes from step S40 to step S48 shown in FIG. 7, respectively, and therefore will not be described here.

[0110] (Reader device processing) The group formation process of the wireless communication system according to the embodiment will be described with reference to Fig. 12. Fig. 12 is a sequence diagram showing the flow of the group formation process of the wireless communication system according to the embodiment.

[0111] 12 mainly shows the process executed by the leader device 20 when forming a group. In FIG. 12, the process is performed when a group join request message cannot be received from the general device 30.

[0112] The processes from step S100 to step S112 are the same as the processes from step S10 to step S22 shown in FIG. 7, respectively, and therefore will not be described again.

[0113] The timer unit 96 of the leader device 20 waits for the time limit to elapse and ends the group creation timer (step S114). That is, the leader device 20 does not receive a group join request message from the general device 30 during the period from when the group creation timer was started to when it was ended. Then, the process proceeds to step S116.

[0114] The message generating unit 94 of the leader device 20 generates a group creation completion message (NG) indicating that the group has not been formed (step S116), and the process then proceeds to step S118.

[0115] The transmitter 70 of the leader device 20, under the control of the communication control unit 90, switches the channel to CH1 and transmits a group creation completion message (NG) to the management device 10 (step S118). If the group cannot be formed, the leader device 20 returns to CH1 from the channel set for itself under the control of the communication control unit 90. For example, if the leader device 20 is the leader device 20-1, the communication control unit 90 of the leader device 20-1 executes a process of returning from CH2 to CH1.

[0116] (General equipment processing) The group formation process of the wireless communication system according to the embodiment will be described with reference to Fig. 13. Fig. 13 is a sequence diagram showing the flow of the group formation process of the wireless communication system according to the embodiment.

[0117] Fig. 13 mainly shows the processing executed by the general device 30 when forming a group. Fig. 13 shows the processing when the general device 30 applies to join a group. In the example shown in Fig. 13, for simplicity of explanation, two leader devices 20, leader device 20-1 and leader device 20-2, are shown, but the present invention is not limited to this.

[0118] The process of step S130 is the same as the process of step S10 shown in FIG. 7, and therefore a description thereof will be omitted.

[0119] The transmitting unit 40 of the management device 10 transmits a group creation request message to the leader device 20 and the general device 30 via CH1 under the control of the communication control unit 60 (step S132). Then, the process proceeds to step S134.

[0120] The receiving unit 102 of the general device 30 receives the group creation request message from the management device 10 under the control of the communication control unit 120 (step S134). Then, the process proceeds to step S136.

[0121] The timer unit 126 of the general device 30 activates a group creation processing timer with a time limit of the first time for forming a group, and the mode setting unit 128 sets the general device 30 to the group creation mode (step S136). There is no particular limit on the time limit, but the timer unit 126 may set the time limit according to the number of general devices 30 that are the targets of the group. For example, the timer unit 126 may set a longer time limit if the number of general devices 30 is large and a shorter time limit if the number is small. For example, the timer unit 126 may set a time limit according to the number of leader devices 20 included in the wireless communication system 1. For example, the timer unit 126 may set a time limit of about one second per leader device 20. Although not shown, upon receiving the group creation request message from the management device 10, the timer unit 96 of the leader device 20 activates the group creation timer that specifies the time limit for creating the group described above. Then, the process proceeds to step S138.

[0122] The message generator 94 of the leader device 20-1 generates a group join request message requesting the general device 30 to join the group (step S138), and then the process proceeds to step S140.

[0123] The transmitter 70 of the leader device 20-1 transmits a group join request message to the general device 30 on the channel CH1 under the control of the communication control unit 90 (step S140), and then the process proceeds to step S142.

[0124] The receiving unit 102 of the general device 30 receives the group join request message from the leader device 20-1 under the control of the communication control unit 120 (step S142), and then the process proceeds to step S144.

[0125] The control unit 114 of the general device 30 stores the ID and RSSI value of the leader device 20-1 in the storage unit 110 (step S144). Specifically, the control unit 114 associates the ID of the leader device 20-1 that transmitted the group join request message with the RSSI value at the time of receiving the group join request message and stores them in the storage unit 110. For example, if the RSSI value is "-98 dBm," the control unit 114 associates "UID2," which is the ID of the leader device 20-1, with "-98 dBm" and stores them in the storage unit 110. Then, the process proceeds to step S146.

[0126] The message generator 94 of the leader device 20-2 generates a group join request message requesting the general device 30 to join the group (step S146), and then the process proceeds to step S148.

[0127] The transmitter 70 of the leader device 20-2 transmits a group join request message to the general device 30 on the channel CH1 under the control of the communication control unit 90 (step S148), and then the process proceeds to step S150.

[0128] The receiving unit 102 of the general device 30 receives the group join request message from the leader device 20-2 under the control of the communication control unit 120 (step S150).

[0129] The control unit 114 of the general device 30 stores the ID and RSSI value of the leader device 20-2 in the storage unit 110 (step S152). Specifically, the control unit 114 associates the ID of the leader device 20-2 that transmitted the group join request message with the RSSI value at the time of receiving the group join request message and stores them in the storage unit 110. For example, if the RSSI value is "-100 dBm," the control unit 114 associates "UID3," which is the ID of the leader device 20-2, with "-100 dBm" and stores them in the storage unit 110. Then, the process proceeds to step S154.

[0130] The timer unit 126 of the general device 30 waits for the first time to elapse, and ends the group creation processing timer, and the mode setting unit 128 cancels the group creation mode setting of the general device 30 (step S154). Then, the process proceeds to step S156.

[0131] In this embodiment, in steps S136 to S154, the general device 30 associates the IDs and RSSI values ​​of the leader device 20-1 and the leader device 20-2 and stores them, but the present invention is not limited to this. In practice, the general device 30 receives group join request messages on the CH1 channel from multiple leader devices 20. Then, the general device 30 associates the IDs and RSSI values ​​of the multiple leader devices 20 and stores them in the storage unit 110.

[0132] The selection unit 130 of the general device 30 selects a leader device 20 to join the group (step S156). Specifically, the selection unit 130 refers to the RSSI values ​​stored in the storage unit 110, and selects the leader device 20 having the ID associated with the highest RSSI value as the leader device 20 to join the group. In the example shown in FIG. 13, for example, if the RSSI value of the leader device 20-1 is "-98 dBm" and the RSSI value of the leader device 20-2 is "-100 dBm," the selection unit 130 selects the leader device 20-1 as the leader device 20 to join the group. Then, the process proceeds to step S158.

[0133] The message generator 124 of the general device 30 generates a group join request message indicating a request to join the group to the leader device 20-1 (step S158), and then the process proceeds to step S160.

[0134] The transmitting unit 100 of the general device 30 transmits a group join request message to the leader device 20-1 under the control of the communication control unit 120 (step S160). Specifically, the transmitting unit 100 switches the channel to be used from CH1 to CH2 under the control of the communication control unit 120, and transmits the group join request message to the leader device 20-1. Then, the process proceeds to step S162.

[0135] The receiving unit 72 of the leader device 20-1 receives a group join request message from the general device 30 under the control of the communication control unit 90 (step S162). Although not shown in the figure to mainly explain the processing of the general device 30, the leader device 20-1 executes processing equivalent to updating the accommodation capacity (step S32) and storing the ID and RSSI value (step S34) in Fig. 7. Then, the process proceeds to step S164.

[0136] The message generator 94 of the leader device 20-1 generates a group joining permission / denial message (step S164). Specifically, the message generator 94 of the leader device 20-1 generates a group joining permission / denial message (OK) indicating that joining to the group is permitted. Then, the process proceeds to step S166.

[0137] The transmitter 70 of the leader device 20-1 transmits a group joining permission / denial message (OK) to the general device 30 on the channel CH2 under the control of the communication control unit 90 (step S166). Then, the process proceeds to step S168.

[0138] The receiving unit 102 of the general device 30 receives the group joining permission / denial message (OK) from the leader device 20-1 under the control of the communication control unit 120 (step S168), and then the process proceeds to step S170.

[0139] The display control unit 132 of the general device 30 displays the ID and RSSI value of the leader device 20-1 (step S170). Fig. 14 is a diagram showing an example of a display screen of the general device according to the embodiment.

[0140] 14, the display screen 500 displays "UID2" which is the ID of the reader device 20-1 and "-98 dBm" which is the RSSI value. This allows the user of the general device 30 to easily understand his / her own reader device 20 and the RSSI value of that reader device 20. By pressing a Menu button 510 on the display screen 500, the user can display a main menu for selecting various operations.

[0141] Returning to Fig. 13, the transmitting unit 70 of the leader device 20-1 transmits audio signals and various information to the general device 30 through the channel CH2 under the control of the communication control unit 90 (step S172).

[0142] The receiving unit 102 of the general device 30 receives the audio signal and various information from the leader device 20-1 under the control of the communication control unit 120 (step S174), and then the process proceeds to step S176.

[0143] The control unit 114 of the general device 30 updates the RSSI value of the leader device 20-1 stored in the storage unit 110 (step S176). Specifically, the control unit 114 updates the RSSI value of the leader device 20-1 stored in the storage unit 110 when receiving an audio signal or various information. Furthermore, based on the operation timer started in step S48 of FIG. 7 and step S94 of FIG. 11, the leader device 20-1 may transmit a signal strength update request signal at predetermined intervals of a predetermined second time, thereby causing the control unit 114 to update the RSSI value of the leader device 20-1 at predetermined intervals. In this way, the RSSI value of the leader device 20-1 stored in the storage unit 110 is updated, making it possible to check the latest reception status.

[0144] (General equipment processing) The group formation process of the wireless communication system according to the embodiment will be described with reference to Fig. 15. Fig. 15 is a sequence diagram showing the flow of the group formation process of the wireless communication system according to the embodiment.

[0145] Fig. 15 mainly shows the processing executed by the general device 30 when forming a group. Fig. 15 shows the processing when the general device 30 dynamically changes the group to which it joins. In the example shown in Fig. 15, for simplicity of explanation, the processing when the general device 30 changes the group between two leader devices 20-1 and 20-2 is shown, but the present invention is not limited to this.

[0146] The processing from step S180 to step S212 is the same as the processing from step S130 to step S162 shown in Fig. 13, respectively, and therefore description thereof will be omitted. Then, although not shown in Fig. 15 in order to mainly explain the processing of the general device 30, the leader device 20-1 executes processing equivalent to updating the accommodation number (step S32) and storing the ID and RSSI value (step S34) in Fig. 7.

[0147] The message generator 94 of the leader device 20-1 generates a group join permission / denial message (step S214). Specifically, the message generator 94 of the leader device 20-1 generates a group join permission / denial message (NG) indicating that joining the group is denied because the current capacity has reached the maximum. Then, the process proceeds to step S216.

[0148] The transmitter 70 of the leader device 20-1 transmits a group joining permission / refusal message (NG) to the general device 30 via CH2 under the control of the communication control unit 90 (step S216). Then, the process proceeds to step S218.

[0149] The receiving unit 102 of the general device 30 receives the group joining permission / refusal message (NG) from the leader device 20-1 under the control of the communication control unit 120 (step S218), and then proceeds to step S220.

[0150] The selection unit 130 of the general device 30 selects a leader device 20 to join the group (step S220). Specifically, the selection unit 130 refers to the RSSI values ​​stored in the storage unit 110, and since the selection unit 130 has received a message rejecting joining the group from the leader device 20-1 whose ID is associated with the highest RSSI value, selects the leader device 20 with the next highest RSSI value as the leader device 20-2 to join the group. Then, the process proceeds to step S222.

[0151] The message generator 124 of the general device 30 generates a group join request message indicating a request to join the group to the leader device 20-2 (step S222), and then the process proceeds to step S224.

[0152] The transmitting unit 100 of the general device 30 transmits a group join request message to the leader device 20-2 on the channel CH3 under the control of the communication control unit 120 (step S224), and then the process proceeds to step S226.

[0153] The receiving unit 72 of the leader device 20-2 receives a group join request message from the general device 30 under the control of the communication control unit 90 (step S226). Although not shown in Fig. 15 to mainly explain the processing of the general device 30, the leader device 20-1 executes processing equivalent to updating the accommodation capacity (step S32) and storing the ID and RSSI value (step S34) in Fig. 7. Then, the process proceeds to step S228.

[0154] The message generator 94 of the leader device 20-2 generates a group joining permission / denial message (step S228). Specifically, the message generator 94 of the leader device 20-2 generates a group joining permission / denial message (OK) indicating that joining to the group is permitted. Then, the process proceeds to step S230.

[0155] The transmitter 70 of the leader device 20-2 transmits a group joining permission / denial message (OK) to the general device 30 via CH3 under the control of the communication control unit 90 (step S230). Then, the process proceeds to step S232.

[0156] The receiving unit 102 of the general device 30 receives the group joining permission / denial message (OK) from the leader device 20-2 under the control of the communication control unit 120 (step S232), and then proceeds to step S234.

[0157] The display control unit 132 of the general device 30 displays the ID and RSSI value of the leader device 20-2 (step 234). The display screen is the same as the example shown in Fig. 14, so a description thereof will be omitted.

[0158] [Group Update Process] A group update process in the wireless communication system according to the embodiment will be described with reference to Fig. 16. Fig. 16 is a sequence diagram showing the flow of a group formation process in the wireless communication system according to the embodiment.

[0159] FIG. 16 shows the process when a general device 30 that has joined a group of the leader device 20-2 updates the group to join to the group of the leader device 20-1.

[0160] The message generator 124 of the general device 30 generates a group leave message indicating that the general device 30 will leave the group of the leader device 20-2 (step S240). Specifically, when the control unit 114 determines that the RSSI value of the signal received from the leader device 20-2 is below a predetermined threshold, the message generator 124 generates the group leave message. The group leave message is also called a group leave signal. Although not shown in FIG. 16, in steps S174 and S176 of FIG. 13 described above, the general device 30 updates the RSSI value of the leader device 20 every time it receives a voice signal or various information from the leader device 20 of the group it has joined. Furthermore, based on the operation timer started in step S48 of FIG. 7 or step S94 of FIG. 11, the general device 30 updates the RSSI value of the leader device 20 every time it receives a signal strength update request signal transmitted from the leader device 20 of the group at second time intervals. Then, the process proceeds to step S242.

[0161] The transmitting unit 100 of the general device 30 transmits a group leave message to the leader device 20-2 on the channel CH3 under the control of the communication control unit 120 (step S242), and then the process proceeds to step S244.

[0162] The receiving unit 72 of the leader device 20-2 receives the group leave message from the general device 30 under the control of the communication control unit 90 (step S244). As a result, although not shown, the leader device 20-2 detects that there has been a change in the general devices 30 included in the group, and updates the display screen in Fig. 8. Then, the process proceeds to step S246.

[0163] The message generator 94 of the leader device 20-2 generates a group update message (step S246). The group update message is also called a group update signal. Then, the process proceeds to step S248.

[0164] The transmitter 70 of the leader device 20-2 transmits a group update message to the management device 10 on the CH1 channel under the control of the communication control unit 90 (step S248). As a result, although not shown, the management device 10 detects that there has been a change in the general devices 30 accommodated in the group of the leader device 20-2, and updates the display screens of Figures 9A, 9B, and 10. Then, the process proceeds to step S250.

[0165] The timer unit 126 of the general device 30 starts a group rejoining timer that specifies a time limit for executing the rejoining process to the group (step S250). Specifically, the timer unit 126 starts a group rejoining timer that specifies a time limit for executing the rejoining process for the leader device 20-1. Then, the process proceeds to step S252.

[0166] The message generator 124 of the general device 30 generates an RSSI value level request message indicating a request for an RSSI value (step S252). The RSSI value level request message is also called a radio wave intensity request signal. Then, the process proceeds to step S242.

[0167] The transmitting unit 100 of the general device 30 transmits an RSSI level request message to the leader device 20-1 on the channel CH2 under the control of the communication control unit 120 (step S254), and then the process proceeds to step S256.

[0168] The receiving unit 72 of the leader device 20-1 receives the RSSI level request message from the general device 30 under the control of the communication control unit 90 (step S256). Then, the process proceeds to step S258.

[0169] The message generator 94 of the leader device 20-1 generates an RSSI level response message indicating the RSSI value (step S258). The RSSI level response message is also called a radio wave intensity response signal. Then, the process proceeds to step S260.

[0170] The transmitter 70 of the leader device 20-1 transmits an RSSI response message to the general device 30 on the channel CH2 under the control of the communication control unit 90 (step S260), and then the process proceeds to step S262.

[0171] The receiving unit 102 of the general device 30 receives the RSSI response message from the leader device 20-1 under the control of the communication control unit 120 (step S262), and then the process proceeds to step S264.

[0172] The timer unit 126 of the general device 30 waits for the time limit to elapse and ends the group rejoining timer (step S264), and then the process proceeds to step S266.

[0173] The control unit 114 of the general device 30 stores the ID and RSSI value of the leader device 20-1 in the storage unit 110 (step S266). Specifically, the control unit 114 associates the ID of the leader device 20-1 that transmitted the RSSI response message with the RSSI value of the signal when the RSSI response message was received, and stores them in the storage unit 110. For example, if the RSSI value is "-98 dBm," the control unit 114 associates "UID2," which is the ID of the leader device 20-1, with "-98 dBm," and stores them in the storage unit 110. Then, the process proceeds to step S268.

[0174] The timer unit 126 of the general device 30 starts a group rejoining timer that specifies a time limit for executing the rejoining process to the group (step S268). Specifically, the timer unit 126 starts a group rejoining timer that specifies a time limit for executing the rejoining process for the leader device 20-2. Then, the process proceeds to step S270.

[0175] The message generator 124 of the general device 30 generates an RSSI value level request message indicating a request for an RSSI value (step S270), and then the process proceeds to step S272.

[0176] The transmitting unit 100 transmits an RSSI level request message to the leader device 20-1 on the channel CH3 under the control of the communication control unit 120 (step S272), and then the process proceeds to step S274.

[0177] The receiving unit 72 of the leader device 20-2 receives the RSSI value request message from the general device 30 under the control of the communication control unit 90 (step S274).

[0178] The message generator 94 of the leader device 20-2 generates an RSSI response message for indicating the RSSI value (step S276), and then the process proceeds to step S278.

[0179] The transmitter 70 of the leader device 20-2 transmits the RSSI response message to the general device 30 on the channel CH3 under the control of the communication control unit 90 (step S278). Then, the process proceeds to step S280.

[0180] The receiving unit 102 of the general device 30 receives the RSSI response message from the leader device 20-2 under the control of the communication control unit 120 (step S280), and then the process proceeds to step S282.

[0181] The timer unit 126 of the general device 30 waits for the time limit to elapse and ends the group rejoining timer (step S282), and then the process proceeds to step S284.

[0182] The control unit 114 stores the ID and RSSI value of the leader device 20-2 in the storage unit 110 (step S284). Specifically, the control unit 114 associates the ID of the leader device 20-2 that transmitted the RSSI response message with the RSSI value at the time of receiving the RSSI response message and stores them in the storage unit 110. For example, if the RSSI value is "-100 dBm," the control unit 114 associates "UID3," which is the ID of the leader device 20-2, with "-100 dBm" and stores them in the storage unit 110. Then, the process proceeds to step S286.

[0183] In this embodiment, in steps S250 to S284, the general device 30 associates the IDs of the reader devices 20-1 and 20-2 with the RSSI values ​​and stores them, but the present invention is not limited to this. In practice, the general device 30 transmits RSSI level request messages to all reader devices 20 on channels corresponding to the reader devices 20. Then, the general device 30 associates the IDs of all reader devices 20 with the RSSI values ​​and stores them in the storage unit 110.

[0184] The selection unit 130 of the general device 30 selects the leader device 20 of the group to rejoin (step S286). Specifically, the selection unit 130 refers to the RSSI values ​​stored in the storage unit 110, and selects the leader device 20 with the ID associated with the highest RSSI value as the leader device 20 to join the group. In this embodiment, the channel set for the leader device 20 with the ID associated with the highest RSSI value is called the third channel. In the example shown in FIG. 16, the selection unit 130 selects the leader device 20-1 as the leader device 20 to join the group. Then, the process proceeds to step S288.

[0185] The message generator 124 generates a group join request message requesting leader device 20-1 to join the group (step S288), and then the process proceeds to step S290.

[0186] The transmitting unit 100 of the general device 30 transmits a group join request message to the leader device 20-1 on the channel CH2 under the control of the communication control unit 120 (step S290). In the example shown in Fig. 16, CH2 is the third channel.

[0187] The receiving unit 72 of the leader device 20-1 receives the group join request message from the general device 30 under the control of the communication control unit 90 (step S292). Then, the process proceeds to step S294.

[0188] The message generator 94 of the leader device 20-1 generates a group joining permission / denial message (step S294). Specifically, the message generator 94 of the leader device 20-1 generates a group joining permission / denial message (OK) indicating that joining to the group is permitted. As a result, although not shown, the leader device 20-1 detects that there has been a change in the general devices 30 accommodated in the group, and updates the display screen in FIG. 8. Then, the process proceeds to step S296.

[0189] The transmitter 70 of the leader device 20-1 transmits a group joining permission / refusal message (OK) to the general device 30 on the CH2 channel under the control of the communication control unit 90 (step S296). Also, although not shown, the transmitter 70 of the leader device 20-1 transmits a group update message to the management device 10 in the same manner as in step S248 described above, to notify that there has been a change in the general devices 30 accommodated in the group. Then, the process proceeds to step S298.

[0190] The receiving unit 102 of the general device 30 receives the group joining permission / denial message (OK) from the leader device 20-1 under the control of the communication control unit 120 (step S298), and then the process proceeds to step S300.

[0191] The display control unit 132 of the general device 30 displays the ID and RSSI value of the leader device 20-1 (step S300). The display screen is the same as the example shown in Fig. 14, so a description thereof will be omitted.

[0192] As described above, in this embodiment, by transmitting and receiving various signals between the management device 10, the leader device 20, and the general device 30, it becomes possible to change the group without going through a base station.

[0193] The components of each device shown in the figure are conceptual functional components and do not necessarily have to be physically configured as shown. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads and usage conditions. This distribution and integration configuration may also be performed dynamically.

[0194] Although the embodiments of the present invention have been described above, the present invention is not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments. [Explanation of symbols]

[0195] 10 Management device 20 Reader device 30 General equipment 40,70,100 Transmitter 42, 72, 102 Receiver 44,74,104 Input section 46,76,106 Display section 48,78,108 Audio output section 50,80,110 storage section 52, 82, 112 GNSS receiver 54,84,114 Control section 60,90,120 Communication control unit 62,92,122 Location information acquisition unit 64,94,124 Message Generation Unit 66,98,132 Display control unit 96,126 Timer section 128 Mode setting section 130 Selection Section

Claims

1. a receiving unit that receives a group creation request signal from the management device and a group joining request signal from each of the plurality of leader devices via a first channel; a mode setting unit that sets the device itself to a group creation mode for a predetermined first time period when the device receives the group creation request signal; a storage unit that receives a group join request signal from each of the plurality of leader devices during the group creation mode, and stores the radio wave intensity at the time of receiving the group join request signal and the identifier of the leader device that transmitted the group join request signal in association with each other; a selection unit that selects the leader device whose radio wave intensity stored in the storage unit is the maximum value when the period of the group creation mode ends; a transmitter that transmits a group join request signal to the leader device selected by the selector on a second channel different from the first channel; A wireless communication device comprising:

2. the receiving unit receives a group join request signal, which is a response to the transmitted group join request signal, via the second channel; If the group joining permission signal is a signal permitting joining to the group, the receiving unit and the transmitting unit communicate with another wireless communication device on the second channel. The wireless communication device according to claim 1 .

3. the storage unit pre-stores a channel list in which an identifier of the reader device is associated with a channel used by the reader device; the second channel is a channel associated with the identifier of the reader device having the maximum radio wave intensity stored in the storage unit; 3. The wireless communication device according to claim 1.

4. a control unit that causes the transmitting unit to transmit a group leave signal on the second channel when the radio wave intensity when the receiving unit receives a signal on the second channel from the leader device becomes lower than a preset threshold; the transmitting unit, after transmitting the group leaving signal, sequentially transmits radio wave intensity request signals to the plurality of reader devices on the channels associated with the reader devices stored in the storage unit; the receiving unit sequentially receives radio wave intensity response signals from a plurality of reader devices on a channel associated with the reader device; the storage unit stores the radio wave intensity of the radio wave intensity response signal in association with an identifier of the reader device that transmitted the radio wave intensity response signal; the selection unit selects the reader device having the maximum radio wave intensity when receiving the radio wave intensity response signal stored in the storage unit; the transmitting unit transmits a group joining request signal on a third channel associated with the leader device selected by the selecting unit. The wireless communication device according to claim 1 .

5. receiving a group creation request signal from the management device and a group joining request signal from each of the plurality of leader devices via a first channel; setting the device itself into a group creation mode for a predetermined first time period when the device receives the group creation request signal; receiving a group join request signal from each of the plurality of leader devices during the group creation mode, and storing in a storage unit the radio wave intensity at the time of receiving the group join request signal and the identifier of the leader device that transmitted the group join request signal in association with each other; selecting the leader device whose radio wave intensity stored in the storage unit is the maximum value when the period of the group creation mode has ended; transmitting a group join request signal to the selected leader device on a second channel different from the first channel; A wireless communication method comprising:

Images