HK1223467B - Relay apparatus, voice-communication system, method for relaying voice signals, and recording medium - Google Patents

Description

Relay device, voice communication system, voice signal relay method, and recording medium

Technical Field

The present invention relates to a voice communication system utilizing a network such as a wireless LAN.

Background Art

Conventionally, so-called wireless communication devices, which modulate a high-frequency carrier wave (a continuous-time signal) with an analog or digital signal and transmit it, have been the mainstream for wireless voice communication. While one-to-one communication is the basic function of wireless communication devices, some have also been proposed, featuring group communication capabilities that allow multiple wireless communication devices to communicate simultaneously.

Conventional wireless communication devices can communicate with other wireless communication devices within the range of their own radio waves. However, in recent years, wireless communication systems have become available that connect multiple transponders via a network, as described in Patent Document 1. Wireless communication devices can communicate with each other within the communication area formed by the coverage areas of these multiple transponders, thus extending the communication range compared to the past.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2009-267911

Summary of the Invention

Problems to be solved by the invention

The wireless communication device described above can perform group communication within the communication range, but when the communication range is divided into multiple areas, it is difficult to call only wireless communication devices in the area near the device itself, etc., or to call only wireless communication devices in a certain area.

The object of the present invention is to provide a voice communication system that connects a relay device and a terminal device serving as a communication machine via a communication network, and enables the relay device to manage the current location of the terminal device, thereby enabling calls to terminal devices in units of areas to be implemented with a simple structure.

Means for solving problems

The relay device of the present invention includes a network communication unit, a control unit, and a storage unit. The network communication unit communicates with a plurality of terminal devices via a communication network including a wireless network. The control unit controls the communication of audio signals between the relay device and the terminal devices.

The control unit divides the communication area of the communication network into a plurality of partial communication areas and stores location information indicating in which partial communication area each terminal device is located in the storage unit. When a call is made from a calling terminal device, one of the terminal devices, specifying a partial communication area, the control unit establishes a communication session between the calling terminal device and a terminal device located in the specified partial communication area, and forwards audio signals received from the terminal device participating in the communication session to the other terminal devices participating in the communication session.

The voice signal relay method of the present invention relays voice signals using a relay device comprising a network communication unit for communicating with terminal devices via a network and a storage unit for storing the location information of the terminal devices. In step 1, the communication area of the communication network is divided into a plurality of partial communication areas, and location information indicating which partial communication area each terminal device is located in is stored in the storage unit. In step 2, when a call is placed from a calling terminal device, one of the terminal devices, specifying a partial communication area, a communication session is established between the calling terminal device and the terminal devices located in the specified partial communication area. In step 3, voice signals received from the terminal devices participating in the communication session are forwarded to the other terminal devices participating in the communication session.

The program of the present invention causes a control unit of a relay device, which includes a network communication unit for communicating with terminal devices via a network and a storage unit for storing location information of the terminal devices, to function as first, second, and third units. The first unit divides the communication area of the communication network into a plurality of partial communication areas and stores location information indicating in which partial communication area each terminal device is located in the storage unit. When a call is made from a calling terminal device, one of the terminal devices, specifying a partial communication area, the second unit establishes a communication session between the calling terminal device and a terminal device located in the specified partial communication area. The third unit forwards audio signals received from a terminal device participating in the communication session to the other terminal devices participating in the communication session.

The call specifying a partial communication area may be a call specifying a partial communication area where the calling terminal device is located (a neighboring call).

When a call is made from a calling terminal device specifying a partial communication area and an existing group, a communication session may be established in which the calling terminal device and terminal devices located in the specified partial communication area and belonging to the specified existing group participate.

Alternatively, when a terminal device located outside a designated partial communication area moves and enters the designated partial communication area, the terminal device may be allowed to participate in the communication session. In this case, belonging to an existing group may be a condition.

When a terminal device participating in a communication session moves outside a designated partial communication area, the terminal device may be excluded from the communication session.

The communication network may have multiple wireless access points. Each terminal device may connect to the communication network via any wireless access point. Each partial communication area may be comprised of the coverage area of one or more wireless access points, and information indicating which wireless access point each terminal device is connected to may be stored in the storage unit as location information. A call made by a calling terminal device that specifies a partial communication area may specify any wireless access point.

The control unit of the relay device may receive information on the connected wireless access point from the terminal device periodically or at a predetermined timing to update the position information stored in the storage unit.

The voice communication system of the present invention includes a relay device, each connected to a communication network, and multiple terminal devices. The relay device includes a network communication unit for communicating with the multiple terminal devices via the communication network, a control unit for controlling the communication of voice signals between the relay device and the terminal devices, and a storage unit. The control unit divides the communication area of the communication network into multiple partial communication areas and stores location information indicating which partial communication area each terminal device is located in in the storage unit. Furthermore, when a call is made from a calling terminal device, one of the terminal devices, specifying a partial communication area, the control unit establishes a communication session between the calling terminal device and a terminal device located in the specified partial communication area, and performs relay processing to forward voice signals received from the terminal device participating in the communication session to the other terminal devices participating in the communication session. The terminal device includes: a terminal network communication unit for communicating with the relay device via the communication network; a location information acquisition unit for acquiring its own location information; a location information update unit for transmitting the acquired location information to the relay device; and a calling unit for transmitting a call specifying any of the partial communication areas to the relay device in response to a specific user operation.

In the above-mentioned voice communication system, the communication network may include multiple wireless access points, and multiple terminal devices may connect to the communication network via any of the wireless access points. Each functional unit operates as follows. The control unit of the relay device divides the communication area into sections corresponding to the coverage areas of one or more wireless access points, thereby defining partial communication areas. The terminal network communication unit communicates with the relay device via any of the wireless access points. The location information acquisition unit acquires the identification information of the wireless access point with which the terminal device is communicating. The location information update unit transmits the acquired identification information of the wireless access point to the relay device as its own location information. The calling unit transmits a call to the relay device, specifying any of the wireless access points.

In the above-mentioned voice communication system, the calling unit may transmit a call specifying the wireless access point to which the calling unit is connected to the relay device.

In the above-mentioned voice communication system, the terminal device may also have a push-to-talk (PTT) circuit, and the terminal network communication unit sends the voice signal input from the microphone to the relay device when the PTT switch is on, and receives the voice signal sent from the relay device regardless of whether the PTT circuit is on/off.

Effects of the Invention

According to the present invention, by connecting the relay device and the terminal device via a communication network, and having the relay device manage the current location (area) information of each terminal device, mixed groups based on areas are set up, thereby enabling calls to terminal devices based on areas.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a block diagram of a voice communication system according to an embodiment of the present invention.

FIG2 is a block diagram of a transceiver serving as a terminal device.

FIG3 is a diagram showing an example of the structure of a voice data packet.

FIG4 is a block diagram of a management device.

FIG5 is a block diagram of a server device.

FIG6A is a diagram showing a terminal table set in the server device.

FIG6B is a diagram showing a group table set in the server device.

FIG6C is a diagram showing a mixing table set in the server device.

FIG6D is a diagram showing a region table set in the server device.

FIG7A is a diagram showing a hybrid table set in the server device.

FIG7B is a diagram showing a mixing table set in the server device.

FIG8 is a flowchart showing the operation of the transceiver.

FIG9 is a flowchart showing the operation of the transceiver.

FIG10A is a flowchart showing the operation of the server device.

FIG10B is a flowchart showing the operation of the server device.

DETAILED DESCRIPTION

The voice communication system of the present invention will be described with reference to the accompanying drawings. FIG1 is a block diagram of a voice communication system as an embodiment of the present invention. In this voice communication system, multiple terminal devices 14 communicate with each other using a wireless LAN (local area network) 16 such as Wi-Fi. The terminal device 14 has a shape similar to a portable transceiver for wireless communication and, as shown in FIG2 , includes a PTT (push-to-talk) switch 220. Functionally, the terminal device 14 is a wireless network device that transmits and receives voice data packets via wireless access points (APs) 13-1, 13-2, and 13-3 (hereinafter collectively referred to as wireless access points 13). Multiple wireless access points 13 are provided (three in FIG1 ), and each wireless access point 13-1, 2, and 3 is connected to a server device 11 serving as a relay device via a wired network 15. The server device 11 relays communications between the multiple terminal devices 14 via the wired network 15 and the wireless LAN 16. In addition, the wired network 15 and the wireless LAN 16 are collectively referred to as the network 17 hereinafter.

Multiple wireless access points 13 are installed, for example, on each floor or in each room of a building. Each wireless access point 13 covers all or part of the floor or room where it is installed. Server device 11 can estimate which floor or room a terminal device 14 is located in based on which wireless access point 13 the terminal device 14 is communicating with.

When a terminal device 14 is activated within the coverage area of any wireless access point 13, it connects to the network 17. When the terminal device 14 connects to the network 17, the server device 11 transmits configuration data to the terminal device 14, enabling communication with the terminal device 14. The configuration data transmitted by the server device 11 includes, for example, the terminal number that the terminal device 14 can communicate with and an update program. Furthermore, the configuration data is transmitted to the terminal device 14 at appropriate times thereafter. Such appropriate times include, for example, when the terminal device 14 moves into the coverage area of a different wireless access point 13 at regular intervals.

As the wired network 15, an Ethernet (registered trademark) LAN, the Internet, or the like can be used. When the Internet is included in the wired network 15, secure communication can be achieved by using a VPN (Virtual Private Network). Furthermore, as the wireless LAN 16, a communication method compliant with IEEE802.11, such as Wi-Fi, can be used. The terminal device 14 and the wireless access point 13 communicate using the communication method of the wireless LAN 16.

The server device 11 divides the entire coverage area of the voice communication system, consisting of the coverage areas of all wireless access points 13, into multiple partial communication areas to manage communications. In this embodiment, the areas are divided according to the coverage areas of each wireless access point 13, and each area is used as a partial communication area. Alternatively, as shown in the area table in FIG6D , the entire coverage area can be divided according to the coverage areas of one or more wireless access points 13, and each divided area is used as a partial communication area. The server device 11 receives information (SSID) of the connected wireless access point 13 from the terminal device 14 to manage the current location of the terminal device 14.

The terminal device 14 communicates with other terminal devices 14 in the form of individual communication, group communication, full communication (all call) and neighbor communication (neighbor call). Individual communication is a one-to-one communication form in which a terminal device 14 calls another terminal device 14. Group communication is a form in which a terminal device 14 calls a pre-set group and communicates with the terminal devices 14 belonging to the group. Full communication is a form in which all terminal devices 14 that can communicate are connected to the network 17 through a full call of the terminal devices 14. In group communication and full communication, more than three terminal devices 14 can communicate with each other. Neighbor communication is a form in which a terminal device calls a neighbor call to communicate with other terminal devices 14 located in the vicinity of its own terminal device 14. In this embodiment, the coverage area (partial communication area) of the wireless access point 13 to which the terminal device 14 is connected is referred to as the range of the neighbor, that is, the neighbor area. Details about the neighbor communication area will be described later.

The user can select a desired communication method from these by operating the terminal device 14. Furthermore, neighbor communication includes communication with all communicable terminal devices 14 located in the neighboring area (full neighbor communication) and communication with terminal devices 14 located in the neighboring area that belong to a pre-defined group (existing group) (group neighbor communication). In this embodiment, the term "neighbor communication" encompasses both full neighbor communication and group neighbor communication.

In Figure 1, a management device 12 is connected to a wired network 15. The management device 12 is, for example, a personal computer with a management program installed. The management device 12 accesses the server device 11 based on the administrator's operation and sets the table shown in Figure 6A in the server device 11. Furthermore, the management device 12 functions as a terminal device and can communicate with other terminal devices 14. The management device 12 can make calls for individual communication, group communication, and full communication, and can also make calls for area-specific communication. Area-specific communication is a communication method in which the user (administrator) of the management device 12 specifies a partial communication area and the management device 12 calls the terminal devices 14 located in the specified partial communication area to communicate. Area-specific communication, like neighbor communication, also includes communication with all communicable terminal devices 14 located in the specified partial communication area (area-specific full communication) and communication with terminal devices 14 belonging to a pre-defined existing group within the specified partial communication area (area-specific group communication). In this embodiment, the term "area-specific communication" includes both area-specific full communication and area-specific group communication.

Furthermore, proximity communication can also be described as area selection communication in which the coverage area of the wireless access point 13 to which the terminal device 14 is connected is selected as a partial communication area. In this case, the server device 11 selects the partial communication area instead of the user.

Figure 2 is a block diagram of the terminal device 14. As described above, functionally, the terminal device 14 is a wireless network device that transmits and receives voice data packets via the wireless LAN access point (AP) 13. The control unit 20 controls the operation of the terminal device 14 and is comprised of a microprocessor. The control unit 20 includes a storage unit 21 that stores various data. This storage unit 21 stores configuration data downloaded from the server device 11. The control unit 20 is connected to an operation unit 22, a display unit 23, an audio circuit 24, and a wireless LAN communication unit 25. The operation unit 22 includes push switches such as a PTT switch 220. Furthermore, the operation unit 22 receives user operations such as turning on/off the proximity call mode and selecting a target device identification number, and inputs these operation signals to the control unit 20. The target device identification number is a number selected by the user to specify the target device. Individual numbers, group numbers, or global numbers can be used. The target device identification number (target device identification information) corresponds to the forwarding destination information of the present invention. The display unit 23 includes a liquid crystal display. The liquid crystal display displays the communication party identification number selected by the user's operation, the communication party identification number written in the incoming call audio signal, and the like.

The audio circuit 24 includes a microphone 240 and a speaker 241. The control unit 20 decodes received audio data packets and inputs them to the audio circuit 24. The audio circuit converts the decoded audio signal into an analog signal and outputs it from the speaker 241. The audio circuit 24 converts the audio signal input from the microphone 240 into a digital signal and inputs it to the control unit 20. The control unit 20 converts the digital audio signal into audio data packets and inputs them to the wireless LAN communication unit 25. The wireless LAN communication unit 25 includes circuitry for wireless communication using the aforementioned IEEE 802.11 communication method. The wireless LAN communication unit 25 transmits data packets input from the control unit 20 to the wireless access point 13 and inputs data packets received from the wireless access point 13 to the control unit 20.

When the user speaks into the microphone 240 while pressing the PTT switch 220 , the terminal device 14 edits the voice signal into a voice data packet and transmits it to the server device 11 .

The audio data packet is structured as shown in Figure 3. The data body of the audio data packet includes, along with the digitized audio signal, a communication partner identification number, a source terminal number, area information, and a neighbor communication flag. Area information specifies a portion of the communication area in neighbor communication or area-specific communication. In neighbor communication, the number (AP number) of the connected wireless access point 13 is written. In area-specific communication, the information specifying the portion of the communication area (AP number) specified by the user (administrator) of the management device 12 is written. Area information can be written only in neighbor communication or area-specific communication, but can also be written in normal communication formats.

In this embodiment, the SSID of each wireless access point 13 is used as the AP number for identifying the wireless access point 13. In addition, in this embodiment, the MAC address of each wireless access point 13 is used as the SSID of each wireless access point 13. However, the AP number of a wireless access point 13 is not limited to the SSID, and the SSID of a wireless access point 13 is not limited to the MAC address.

The neighbor communication flag is set in the case of neighbor communication or area-specific communication. In the voice data packet of this embodiment, the neighbor communication flag is set in the data body, and the fact that the neighbor communication flag is set can be used to identify neighbor communication or area-specific communication. However, the neighbor communication flag is not required. For example, if the area information is written only in the case of neighbor communication or area-specific communication, the presence or absence of the area information can be used to distinguish between neighbor communication, area-specific communication, and normal communication.

The header of a voice packet contains a destination IP address and a sender address. While the destination IP address of a voice packet sent from terminal device 14 includes the IP address of server device 11, the final destination of the voice signal is not server device 11 but terminal device 14, the other party specified by the other party identification number.

If the server device 11 receives a sound data packet, it extracts the data body from the sound data packet and forwards the sound signal to the terminal device 14 of the communication partner. In the case where the communication partner identification number is a group number and a whole number, the sound signal is forwarded to multiple terminal devices 14 that are the communication partner. That is, in the case of group communication in which the group number is written as the communication partner identification number, the sound signal is forwarded to multiple terminal devices 14 belonging to the group. In addition, in the case of whole communication in which the whole number is written as the communication partner identification number, the sound signal is forwarded to all terminal devices 14 that can communicate. Furthermore, in addition to this, when the neighbor communication flag is set, it is regarded as neighbor communication, and the sound signal is forwarded to the specified group or all terminal devices 14 located in the neighboring area (partial communication area).

Specifically, if the communication partner identification number attached to the audio signal of the audio data packet received by the server device 11 is a group number and the proximity communication flag is set, the audio signal is a proximity group communication audio signal. Therefore, the server device 11 forwards the audio signal to the multiple terminal devices 14 belonging to the group and located in the proximity area. Alternatively, if the communication partner identification number is a group number and the proximity communication flag is set, it is proximity group communication. The server device 11 forwards the audio signal to the terminal devices 14 located in the proximity area of all terminal devices 14 with which communication is possible.

The user operates the terminal device 14 to switch the neighboring call mode (neighboring communication mode) of the terminal device 14 ON/OFF. In addition, when the neighboring communication mode is ON, the user can perform neighboring communication by pressing the PTT switch 220. At this time, the terminal device 14 sets the neighboring communication flag of the voice data packet sent to the server device 11. In addition, neighboring communication is communication with a non-specific terminal device 14 located in the neighboring area or a terminal device 14 belonging to a group. Therefore, when the neighboring communication mode is ON, the operation of the terminal device 14 can also be restricted so that a single communication with a specified terminal device 14 as the communication partner is not accepted.

When forwarding this audio signal, a new audio packet is created with the IP address of the forwarding terminal device 14 as the destination address and the IP address of the server device 11 as the source address. In this new packet, the communication destination identification number and the connecting AP number of the data body are the same as those of the audio packet received by the server device 11. The source terminal number may be cleared or appended with the same source terminal number as that of the audio packet received by the server device 11.

To summarize the above process, when the PTT switch 220 is turned on, the terminal device 14 does not proceed with the communication establishment process such as the SIP process, but instead sends a voice data packet to the server device 11, which is a voice signal input from the microphone 240 and to which the communication party's identification number is appended. The server device 11 forwards this voice signal to the communication party identified by the identification number. In this way, in this voice communication system, communication begins by sending a voice data packet (RTP data packet), so the user can start communication almost simultaneously with turning on the PTT switch 220, and can communicate with the same user experience as a conventional wireless communication transceiver. To achieve this user experience, the server device 11 manages the IP address, group, etc. of each terminal device 14, and forwards the voice signal.

Terminal device 14 not only has a PTT switch 220 but also a VOX circuit. The VOX circuit determines whether a call (voice signal) is being input based on the input level and duration of microphone 240, and switches the device to a transmitting mode (PTT switch on) if a call is detected. Terminal device 14 can use the VOX circuit in place of or in addition to the PTT switch 220 to switch transmission on and off. Conventional wireless communication transceivers are simplex and cannot receive wireless signals while in the transmitting mode. On the other hand, terminal device 14 transmits and receives voice signals using voice packet communication via wireless LAN 16, enabling simultaneous transmission and reception of voice packets. This functionality enables full-duplex communication, allowing simultaneous transmission and reception of voice signals. However, the terminal device 14, using the PTT switch 220 or VOX function, only edits and transmits voice packets when a call is being input, preventing the continuous transmission of silent voice packets even during full-duplex communication.

Figure 4 is a block diagram of the management device 12. As described above, the management device 12 is comprised of, for example, a personal computer with a management program installed. The management device 12 includes a control unit 40, a storage unit 41, a network communication unit 45, an operation unit 42, a display unit 43, and an audio circuit 44. In addition to being able to access the server device 11 in response to an administrator's operation, the management device 12 is also capable of conducting audio communication with other terminal devices 14, similar to the terminal devices 14. The operation unit 42, display unit 43, and audio circuit 44 may also be external components.

The control unit 40 executes management programs stored in the storage unit 41, accesses the server device 11 in response to administrator operations, and controls the operation of devices for communicating with other terminal devices 14, such as the terminal device 14. The storage unit 41 is composed of, for example, a hard disk and RAM. The network communication unit 45 controls communication with the wired network 15.

The operation unit 42 includes input devices such as a keyboard and a mouse, and receives user operations and inputs operation signals to the control unit 40. Operation signals input from the operation unit 42 include, for example, setting/cancelling the area-specific communication mode, specifying an area, and starting/ending a call (PTT operation). The display unit 43 includes a liquid crystal display. The liquid crystal display displays operation screens for setting tables for the server device 11 and for specifying areas. The liquid crystal display also displays the communication partner identification number selected by the user and the communication partner identification number of an incoming call.

As described above, the management device 12 can perform voice communication similarly to the terminal device 14. The management device 12 can perform individual communication, group communication, full communication, and area-specific communication (area-specific group communication and area-specific full communication). The management device 12 performs these communication types using substantially the same processing as the terminal device 14. When performing area-specific communication, the administrator-specified AP number is written into the area information of the voice data packet sent by the management device 12 to the server device 11.

If the communication partner identification number attached to the audio signal of the audio data packet received by the server device 11 from the management device 12 is a group number and the neighbor communication flag is set, the audio signal is an audio signal for area-specific group communication. The server device 11 forwards the audio signal to the terminal devices 14 located in the designated area identified by the AP number in the area information among the multiple terminal devices 14 belonging to the group. Alternatively, if the communication partner identification number is a global number and the neighbor communication flag is set, the audio signal is an audio signal for area-specific global communication. The server device 11 forwards the audio signal to the terminal devices 14 located in the designated area identified by the AP number in the area information among all terminal devices 14 with which communication is possible.

The following describes the forwarding of audio signals by the server device 11. The server device 11 forwards the audio signals contained in audio packets received from terminal devices 14 via network 17 to the communicating terminal devices 14 via network 17. In group communication, the audio signals are forwarded to multiple communicating terminal devices 14. In group communication, multiple users may speak simultaneously, sending audio signals from multiple terminal devices 14 simultaneously. In such cases, the server device 11 mixes the audio signals from these multiple audio packets, compiles a new audio signal, and forwards this new audio signal as an audio packet to each terminal device 14. Furthermore, mixing is performed for each terminal device 14, and the audio signal sent by the server device 11 is not included in the returned audio mix. Specifically, the server device 11 forwards a mixed signal of all received audio signals to terminal devices 14 that are not sending audio signals. For terminal devices 14 that are sending audio signals, the server device 11 excludes the audio signals sent by the terminal devices 14 and forwards a mixed signal of all other audio signals. This prevents echoes of the audio signals sent by the server device 11 at the terminal devices 14. In addition, in the case of overall communication, neighbor communication, and area-specified communication, they are also mixed in the same manner as in the above-mentioned group communication.

Figure 5 is a block diagram of the server device 11. The server device 11 includes a control unit 30, a storage unit 31, and a network communication unit 32. The storage unit 31, which is composed of, for example, a hard disk or RAM, stores the various tables shown in Figure 6 and configuration data for each terminal device 14. The control unit 30 performs configuration of the terminal devices 14, mixing of audio signals, and other operations. The network communication unit 32 controls communication with the wired network 15.

6A , 6B, 6C, and 6D are diagrams showing tables provided in the storage unit 31 of the server device 11 .

Figure 6A shows a terminal table 301. Terminal table 301 is a table used by server device 11 to manage terminal devices 14. Each terminal device 14 is identified by a uniquely assigned identification number (terminal number). Terminal table 301 stores an activation flag, a storage location for configuration data, and a connected AP number for each identification number. The activation flag indicates that the terminal device 14 has connected to network 17 and accessed server device 11, accepting registration and downloading of various data from server device 11. In other words, it indicates that registration is complete and communication is possible. The activation flag is set by server device 11 upon completion of terminal device 14 registration. Configuration data includes, for example, program update data (firmware), a phone book containing information about the group to which the terminal device belongs, and other groups with which communication is permitted. The connected AP number is information used by terminal device 14 to identify the wireless access point 13 to which it is connected. In this embodiment, the SSID of the wireless access point 13 is used as the AP number. This information is used to determine the area in which the terminal device 14 is located.

When the terminal device 14 is activated, it connects to the network 17. When the terminal device 14 connects to the network 17, the server device 11 transmits configuration data to the terminal device 14, performing a registration process to enable communication. The registration process involves setting the activation flag in the terminal table 301, receiving the connected AP number from the terminal device 14, and writing it into the terminal table 301. Furthermore, at an appropriate time thereafter, the server device 11 communicates with the terminal device 14 to update the registration. An example of a registration update is updating the connected AP number. An example of such an appropriate time thereafter is when the connected wireless access point 13 is switched at regular intervals. Registration and registration updates are performed based on a registration request sent from the terminal device 14 to the server device 11. Based on the registration request, the server device 11 registers the terminal device 14 and updates the existing information in the terminal table 301. Alternatively, the management device 12 can update the connected AP number in the terminal table 301. That is, the connected AP number may be updated by a manual operation of an administrator instead of being updated by the server device 11 after receiving it from the terminal device 14 .

In addition, a registration request is also sent to the server device 11 in the form of a voice data packet. The voice data packet containing the registration request is a data packet (RTP data packet) of the same format as the data packet shown in Figure 3, but since it is not a data packet for the purpose of transmitting a voice signal, the data body does not contain a voice signal but is composed only of control information. The control information includes, for example, information indicating that it is a registration request (flag), the number of the connected AP, and the number of the sending source terminal. The communication partner identification number is not required. If the server device 11 receives a voice data packet in this format, it is determined to be a voice data packet of a registration request, and it is not the object of the voice data packet reception processing described in Figure 10A, but a registration processing different from the reception processing is performed.

Furthermore, in terminal table 301 of FIG6A , terminal number "0" indicates management device 12. Specifically, information about management device 12 is stored in the row for terminal number "0" in terminal table 301. Because management device 12 is managed by an administrator and connected to wired network 15, information such as the data storage address and the currently connected AP number is unnecessary and not stored.

If the terminal device 14 downloads information of other activated terminal devices 14, phone books, etc. through registration processing, when the user performs a communication partner selection operation, the terminal number of the above-mentioned activated terminal device 14 and the group number allowed to communicate are displayed as candidates for the communication partner on the display unit 23.

Figure 6B shows group table 302. Group table 302 is a table used by server device 11 to manage groups. Each group is identified by a uniquely assigned identification number (group number). Group table 302 stores the group number and the terminal numbers of the terminal devices 14 belonging to the group (belonging terminal devices) for each group. The number of terminal devices 14 belonging to a group can be one or more. The administrator operates management device 12 to set these terminal table 301 and group table 302 on server device 11.

FIG6C is a diagram showing a hybrid table (session table) 303. FIG7A and FIG7B respectively show examples of registration of neighbor communication sessions and area-specified communication sessions with respect to the hybrid table 303. The hybrid table 303 is a table used by the server device 11 to manage communication sessions. A communication session is a communication state between a plurality of terminal devices 14 using the server device 11 as a relay device. The hybrid table 303 has a plurality of rows, each of which stores information about a communication session. When the server device 11 receives a sound signal (sound data packet) from the terminal device 14, it refers to the hybrid table 303 to determine which communication session the sound signal belongs to.

When the server device 11 receives the calling voice data packet as the first voice data packet from the terminal device 14 , the server device 11 registers the communication session based on the voice data packet in the mixed table 303 .

In the mixed table 303, for each communication session, items including a session number, a calling terminal number, a participating terminal number, an additional terminal number, an excluded terminal number, and a remaining holding time (T1) are provided. The session number is a number that identifies the communication session. The calling terminal number is the terminal number of the terminal device 14 (calling terminal device) that sent the initial voice data packet (call voice data packet) of the communication session. The session number only needs to be a unique value for each communication session. In this embodiment, the communication party identification number written in the above-mentioned call voice data packet is used. A communication session in which a terminal number (e.g., "19") is registered as a session number is a communication session for single communication (single communication session). Single communication refers to one-to-one communication between single terminal devices 14. A communication session in which a group number (e.g., "G1") is registered as a session number is a communication session for group communication (group communication session). Group communication refers to communication in which multiple terminal devices 14 (generally more than three) exchange voice signals with each other. Furthermore, a communication session with the overall number "A" registered as the session number is an overall communication session (overall communication session). Overall communication refers to communication in which all the communicable terminal devices 14 connected to the network 17 exchange voice signals with each other.

The participating terminal numbers are a list of the terminal numbers of the terminal devices 14 (participating terminal devices) participating in the communication session. When a voice packet is transmitted from a terminal device 14 whose terminal number is registered in the participating terminal numbers, the control unit 30 forwards the voice signal of the voice packet to the other terminal devices 14 whose terminal numbers are registered in the participating terminal numbers, thereby enabling mutual communication between the participating terminal devices.

In a group communication session, the participating terminal numbers are the terminal numbers of the calling terminal device and the terminal numbers of the terminal devices 14 belonging to the group designated as the communication partner. However, since terminal devices 14 belonging to the group but not active, or those currently engaged in other individual communication sessions, cannot participate in the group communication session, the terminal numbers of these terminal devices 14 are excluded from the participating terminal numbers (registered in the excluded terminal number entry). Furthermore, if the calling terminal device is a terminal device 14 that does not belong to the group, that is, if the terminal device 14 calls a group other than the one it belongs to, the terminal number of this terminal device 14 is also registered as the participating terminal number. Furthermore, the terminal numbers of additional terminal devices that have been temporarily registered as members are also registered in the additional terminal number entry. In other words, in the group communication session, even if the calling terminal device does not belong to the group, it is treated as a terminal device 14 participating in the communication session, just like terminal devices 14 belonging to the group. The additional terminal number and excluded terminal number entries in the mixed table 303 are not required. Table management can be achieved simply by adding or removing terminal numbers to items that participate in terminal numbers.

In the case of a full communication session, the terminal number of the calling terminal device and the terminal numbers of all communicable terminal devices 14 are registered as participating terminal numbers. Exclusion of terminal numbers is the same as in the above-mentioned group communication. No additional terminal numbers are registered.

In the case of a single communication session, the terminal number of the calling terminal device and the terminal number of the communicating party's terminal device 14 are registered as participating terminal numbers. Since it is a one-to-one communication, the additional terminal number and the excluded terminal number are not registered.

In the case of a neighborhood group communication session, the terminal number of the calling terminal device and the terminal numbers of the terminal devices 14 belonging to the group and located in the designated area (neighboring area) are registered as participating terminal numbers. In the case of a neighborhood-wide communication session, the terminal number of the calling terminal device and the terminal numbers of the terminal devices 14 located in the designated area (neighboring area) among all the terminal devices 14 that can communicate are registered as participating terminal numbers.

For example, in the neighboring communication session with session number "G1" in FIG7A , if terminal devices 14 ("1," "2," "3," "4," and "5") belonging to group number "G1) are located in the area (neighboring area) where terminal device 14 with terminal number "3" is located, which is the calling terminal, terminal devices 14 with terminal numbers "1" and "2" become the communication partners. Therefore, the participating terminal numbers of session number "G1" become "1," "2," and "3." Furthermore, terminal devices 14 with terminal numbers "4" and "5," which belong to group number "G1" but are not located in the neighboring area, are registered as excluded terminals.

In the case of a group communication session with an area specified, the terminal number of the management device 12, which is the calling terminal device, and the terminal numbers of the terminal devices 14 belonging to the group and located in the specified area are registered as participating terminal numbers. In the case of a group communication session with an area specified, the terminal number of the calling terminal device (management device 12) and the terminal numbers of the terminal devices 14 located in the specified area among all the terminal devices 14 capable of communication are registered as participating terminal numbers.

For example, in the area-specific communication session with session number "A" in Figure 7B , if "wireless access point 13-2" is selected as the designated area and, among all terminal devices 14 capable of communication, the only terminal device 14 located in the designated area "wireless access point 13-2" is terminal device 14 with terminal number "99," terminal device 14 with terminal number "99" becomes the communication partner. Therefore, the participating terminal numbers for session number "A" become "0" and "99." Furthermore, terminal devices 14 not located in the designated area "wireless access point 13-2," as well as terminal devices 14 located in the designated area "wireless access point 13-2" but not active, are registered as excluded terminals.

In this way, when a communication session is conducted in the form of neighbor communication or area-specified communication, no information indicating whether it is neighbor communication or area-specified communication is registered in the mixed table 303. Instead, neighbor communication and area-specified communication are corresponded to by adding or deleting the terminal numbers registered in the items of participating terminal numbers.

If a participating terminal device in a proximity communication session or area-specific communication session moves to another area during the communication session, i.e., connects to another wireless access point 13, it is excluded from the participating terminal devices in that communication session at that point in time. Specifically, the terminal number of that terminal device 14 is moved from the participating terminal number entry to the excluded terminal number entry. Conversely, if a terminal device 14 that was excluded from the communication session due to being outside the designated partial communication area in a proximity communication session or area-specific communication session moves into the designated partial communication area, i.e., connects to a designated wireless access point 13, it is registered as a participating terminal device in that communication session at that point in time and becomes able to participate in the communication session.

The hold time in the mixed table 303 is the time during which the communication session is maintained without canceling it even if no voice packets are sent from the participating terminal devices. The hold time for each communication session in the server device 11 is set to 30 seconds, for example. The hold time timer (TS) in the mixed table 303 counts the elapsed hold time when no voice packets are sent. During the processing of the control unit 30 (see FIG. 9 ), the hold time timer TS counts down if no voice packets are sent, and resets to 30 seconds if a voice packet is sent. If the timer TS expires due to no voice packets being sent from the participating terminal devices within 30 seconds, the communication session is canceled, and the information about the communication session is deleted from the mixed table 303.

In a communication session (call), a person's speech is typically several seconds long. The terminal device 14 divides the speech signal into short (20 milliseconds in this embodiment) audio packets and transmits them to the server device 11. Furthermore, in a communication session, the interval (silent period) between one person's speech and the next speaker's speech ranges from zero to several seconds. Therefore, if the hold time is set to 30 seconds, the session will generally not be canceled while the call is ongoing. The hold time for a communication session is not limited to 30 seconds, but should be set to a value greater than the maximum silent period in typical communications. Furthermore, in order to continue the communication session, a hold timer must be kept in each terminal device 14. The hold time (T1) of the terminal device 14 is shorter than the hold time (TS = 30 seconds) of the server device 11. For example, timer T1 is set to 5 seconds. If 5 seconds have passed since the user turned off the PTT switch 220, even if the communication session on the server device 11 is maintained, another communication session can be started by a given operation.

In addition, the mixing table 303 can be divided into two tables consisting of an ongoing mixing table and a backoff table. The ongoing mixing table is a table that registers the currently ongoing mixing session and is formed on a high-speed memory. The session whose communication (transmission and reception of voice data packets) is interrupted is transferred to the backoff table in a short time of about 200 milliseconds and is maintained in the backoff table for a holding time (T1). If communication (transmission and reception of voice data packets) occurs again during the holding time, the communication session is transferred to the ongoing mixing table again for the execution of mixing. In this way, the release of each terminal device 14 from the mixing table 303 can be advanced.

Figures 8 and 9 are flowcharts illustrating the communication control operation of the control unit 20 of the terminal device 14. This process is repeated every 20 milliseconds. During this process, the current communication status is inferred based on the on/off state of the PTT switch 220 and the reception of audio packets (RTP packets). The flags and timers used in this flowchart are as follows.

PTT: is an abbreviation of the push-to-talk switch (PTT switch) 220, but is not limited to the on/off of the PTT switch 220, and also includes the on/off of the transmission signal based on the VOX circuit.

NC0: The communication partner identification number selected by the user (individual number/group number/all number)

NC1: Session number used, a number for identifying the communication session in progress, and the communication partner identification number (individual number/group number/global number) written in the first voice packet that establishes the communication session.

FC: Communication session flag (a flag indicating that the terminal device 14 is participating in a communication session)

FT: Communication flag (a flag indicating that a voice packet is being sent or received)

AC: Neighbor communication flag (a flag indicating that the communication session is neighbor communication or area-specific communication)

T1: Hold time timer (a timer for counting the hold time (5 seconds) of a communication session)

S10 to S22 are voice data packet transmission management processes. The control unit 20 determines the status of the PTT switch 220 (S10). If the PTT switch 220 is on, the control unit 20 proceeds to S11. If the PTT switch 220 is not on, the control unit 20 proceeds to S22. In the description of this flowchart, turning on the PTT switch includes turning on the VOX transmission function.

In S11, the control unit 20 determines whether the communication session flag FC is set. If the communication session flag FC is not set (No in S11), the voice data packet created by turning on the PTT switch 220 this time is a call voice data packet. The control unit 20 sets the communication session flag FC and the communication flag FT indicating that a voice data packet is being sent or received (S12). The control unit 20 transfers the communication partner number NC0 selected by the user to the communication session number NC1 (S13) and determines whether it is neighbor communication or area-specified communication based on the neighbor communication flag AC (S14). If the neighbor communication flag AC is set, it is neighbor communication or area-specified communication. The neighbor communication flag AC is switched between setting and resetting by the user's operation of the terminal device 14.

If the neighbor communication flag AC is set in S14 (Yes in S14), the control unit 20 sends the voice packet with the neighbor communication flag (set), area information (connected AP number), and communication session number NC1 written into the data body along with the voice signal as a call voice packet to the server device 11 (S15). On the other hand, if the neighbor communication flag AC is not set in S14 (No in S14), the control unit 20 sends the voice packet with the neighbor communication flag not written (reset) and the connected AP number and communication session number NC1 written into the data body along with the voice signal as a call voice packet to the server device 11 (S16). By sending this call voice packet, the server device 11 starts a communication session. After resetting the hold time timer T1 to 5 seconds (S17), the control unit 20 advances the processing to the voice packet reception management processing after S30.

If the communication session flag FC is set in S11 (Yes in S11), the control unit 20 determines whether the communication flag FT is set, that is, whether a voice packet is currently being transmitted or received (S18). If the communication flag FT is not set (No in S18), the control unit 20 sets the communication flag FT (S19). The processing proceeds from S11 to S18 to S19 when a new voice packet (the user's conversation voice) is started while the already-started communication session is maintained. In S20, a determination is made as to whether to continue the already-started communication session and return the current voice packet to the communication session (No in S20), or to terminate the previous communication session and send the current voice packet to a new communication partner, that is, to establish a new communication session (Yes in S20). This determination can be made, for example, based on whether a user operation, such as a selection operation of the communication partner, was performed immediately before the current PTT switch 220 was turned on. When the user performs an operation of selecting a new communication partner, in the determination at S20 , a process of establishing a new communication session with the selected communication partner may be performed.

If a new communication session is to be established (YES in S20), the control unit 20 transfers the currently selected communication partner number NC0 to the communication session number NC1 (S21) and proceeds with the process to S14. If an already started communication session is to be continued (NO in S20), the control unit 20 proceeds directly from S20 to S14.

If the PTT switch 220 is not on in S10 (No in S10), the control unit 20 resets the communication flag FT (S22). If the communication flag FT has already been reset, the status quo can be maintained. The control unit 20 then advances the process to the voice packet reception management process from S30 onwards.

In S30, the control unit 20 determines whether a voice packet has been received via the network 17. If a voice packet has been received, the control unit 20 advances the process to S31. If a voice packet has not been received, the control unit 20 advances the process to S40.

In S31, the control unit 20 determines whether the communication session flag FC is set. If the communication session flag FC is not set (No in S31), it determines that a new communication session has been established and its initial voice packet has been sent. The control unit 20 sets the communication session flag FC and the communication in progress flag FT (S33). The FT flag indicates that a voice packet is currently being transmitted or received. The control unit 20 transfers the communication partner number contained in the voice packet to the communication session number NC1 (S34). In S35, the control unit 20 outputs the voice packet to the audio circuit 24 and resets the hold timer T1 to 5 seconds (S36).

If the communication session flag FC is already set in S31 (Yes in S31), the control unit 20 sets the communication flag FT in response to the reception of the current voice packet (S32). If the communication flag FT is already set, the current state can be maintained. The control unit 20 then advances the process to S35.

If no audio data packet is received in S30 (No in S30), the control unit 20 determines whether the communication session flag FC is set (S40). If the communication session flag FC is set (Yes in S40), the control unit 20 executes the processing from S41 onwards. If the communication session flag FC is not set (No in S40), the control unit 20 immediately terminates the processing.

In S41, the control unit 20 determines whether the communication flag FT is set. If the communication flag FT is set (Yes in S41), the control unit 20 immediately terminates the process. If the communication flag FT is not set (No in S41), that is, if the communication flag FT is reset but the communication session flag FC is set, the control unit 20 decrements the hold time timer T1 by 1 (20 milliseconds) (S42). Then, the control unit 20 determines whether the hold time timer T1 has reached 0 due to this subtraction (S43). If the hold time timer T1 has reached 0 (Yes in S43), the control unit 20 resets the communication session flag FC to cancel the communication session (S44). If the hold time timer T1 is still greater than 0 in S43 (No in S43), the control unit 20 immediately terminates the process.

Furthermore, the control unit 40 of the management device 12 also performs substantially the same communication control processing as that performed by the control unit 20 of the terminal device 14 in Figures 8 and 9. However, in S15 of Figure 8 , instead of the number of the wireless access point 13 to which the terminal device is connected, the AP number of the partial communication area specified by the administrator is written into the voice data packet as area information.

10A and 10B are flowcharts showing the operation of the server device 11. Fig. 10A shows the processing when receiving a voice packet, and Fig. 10B shows the mixing table management processing.

In Figure 10A, upon receiving a voice packet, the control unit 30 determines whether the communication session, identified by the source terminal number and the communication partner identification number, has been registered in the hybrid table 303 (S50). If the communication session has been registered in the hybrid table 303 (Yes in S50), the control unit 30 forwards the voice signal contained in the received voice packet to the terminal device 14 participating in the communication session based on the participating terminal number in the hybrid table 303 (S56). The hold timer TS for the communication session in the hybrid table 303 is then reset to 30 seconds (S57). This maintains the communication session in the server device 11 for the next 30 seconds.

If the communication session of the received voice packet is not registered in the hybrid table 303 (No in S50), that is, if the voice packet is a call voice packet, the control unit 30 registers a new communication session based on the call voice packet in the hybrid table 303 (S51). In the hybrid table 303, the communication partner number is registered as the session number, and the terminal number of the terminal device 14 that sent the voice packet is registered as the calling terminal number.

The control unit 30 registers the number of the corresponding terminal device 14 in the items of participating terminal number and excluded terminal number in the communication session column registered in S51 (S52). The registration rules of the items of participating terminal number and excluded terminal number are as follows.

In the case of a single communication session, the terminal number written in the call voice packet as the communication party identification number and the calling terminal number is registered as the participating terminal number.

In a group communication session, the terminal number of the terminal device 14 belonging to the group with the group number, which is written into the call audio data packet as the calling terminal number and the communicating party identification number, is registered as the participating terminal number. Furthermore, if the calling terminal device does not belong to the group, the calling terminal number is also registered as the additional terminal number.

In the case of a neighborhood group communication session or an area-specified group communication session, a communication session is established using the communication partner identification number as the session number, and the terminal numbers of the terminal devices 14 belonging to the group and located in the partial communication area (neighborhood area) specified by the area information are registered as participating terminal numbers. The terminal numbers of the terminal devices 14 belonging to the group but not located in the specified partial communication area are registered as excluded terminal numbers.

In the above-mentioned group communication sessions, neighboring group communication sessions, and area-specified group communication sessions, if there is a terminal device 14 to be registered in the item of participating terminal number that cannot participate in the communication session due to being inactive, participating in other communication sessions, etc., its terminal number is excluded from the item of participating terminal number and transferred to the item of excluded terminal number.

In the case of a full communication session, the terminal numbers of all activated terminal devices 14, including the calling terminal number, are registered as participating terminal numbers. The terminal numbers of inactive terminal devices 14 are registered as excluded terminal numbers. In addition, in the case of a neighbor-wide communication session or an area-specified full communication session, as usual, a communication session is established with the communication partner identification number (the whole number) as the session number, and the terminal numbers of the terminal devices 14 located in the partial communication area (neighboring area) specified by the area information among the activated terminal devices 14 are registered as participating terminal numbers. The terminal numbers of terminal devices 14 that are active but not located in the specified partial communication area are registered as excluded terminal numbers.

In the above steps S51 and S52, a communication session corresponding to the information written into the call audio packet is established, and the participating terminal numbers, etc., are registered. Then, when the terminal devices 14 participating in the communication session transmit a voice signal to the server device using a voice packet obtained by writing the session number of the communication session into the communicating party identification information, the voice signal is forwarded to each participating terminal device. In other words, after establishing a communication session, the terminal devices 14 do not need to distinguish whether the communication session is for proximity communication or area-specific communication.

In addition, the server device 11 also registers the terminal number of the terminal device 14 located in the specified partial communication area into the participating terminal number of the mixed table 303, and registers the terminal numbers other than those in the excluded terminal number, thereby realizing neighbor communication or area-specified communication. Therefore, after establishing a communication session, the server device 11 does not need to distinguish whether the communication session is neighbor communication or area-specified communication.

After establishing the communication session, the control unit 30 transfers the audio signal of the received audio packet to the terminal device 14 participating in the communication session (S53). The terminal device 14 participating in the communication session is determined from the participating terminal numbers of the communication session registered in the mixed table 303.

The control unit 30 determines whether there is a terminal device 14 that has been excluded from the participating terminal devices of the registered communication session due to participating in the communication session established in S51 (S54). That is, this is because each terminal device 14 can only participate in one communication session. Therefore, when a terminal device 14 that participated in the previously established communication session participates in the communication session established this time, it needs to be removed from the previously established communication session. If the corresponding terminal device 14 exists (yes in S54), the terminal number of the terminal device 14 is deleted from the participating terminal number of the previously established communication session (S55). The excluded terminal number is transferred to the excluded terminal number. In this way, the participating terminal devices of each communication session are optimized.

The hybrid table management process shown in FIG10B is repeated periodically (e.g., every 20 milliseconds). The control unit 30 first specifies the communication session in the first row of the hybrid table 303 (S60). The control unit 30 decrements the hold time timer TS for the specified communication session by 1 (20 milliseconds) (S61) and determines whether the hold time timer TS has reached 0 as a result of this subtraction (S62). If the hold time timer TS has reached 0 (YES in S62), the control unit 30 deems the communication session to have ended and deletes the communication session in that row (S63).

The control unit 30 sequentially executes the above-described processing until the final row of the hybrid table 303 ( S64 , S65 ), thereby managing the hybrid table 303 .

In the voice communication system of this embodiment, the server device 11 manages the area where each terminal device 14 is located using multiple wireless access points 13 installed in multiple areas, thereby enabling communication management within the area defined by the terminal device 14. Furthermore, the server device 11 can also add or remove participating terminal devices during normal group and group communications, leveraging this capability to operate a communication session defined within an area. This allows the operation of a communication session defined within an area to be performed using substantially the same processing as a normal communication session. The terminal device 14 can implement calls defined within an area by appending information specifying the area to the voice packets used to transmit the call.

In the above embodiment, the area is divided into sections for each coverage area of each wireless access point 13, and each section is used as a partial communication area. However, the coverage areas of multiple wireless access points 13 can also be used as a single partial communication area. In this case, the server device 11 can configure a section table as shown in FIG6D to control each partial communication area.

Figure 6D shows a region table. As described above, region table 304 is a table used to manage partial communication areas. In region table 304, AP numbers, which identify wireless access points 13 located in each partial communication area, are registered in association with area numbers uniquely assigned to each partial communication area. As described above, in this embodiment, the SSID of the wireless access point 13 is used as the AP number, and the MAC address of the wireless access point 13 is used as the SSID. The server device 11 searches region table 304 using the connected AP number from terminal table 301 to detect the partial communication area where the terminal device 14 is located.

The area table shown in FIG. 6D is used only for area-specified communication, and neighbor communication can also be used in neighboring areas (partial communication areas) divided for each wireless access point 13 .

Furthermore, in proximity communication, an area wider than the coverage area of a single wireless access point 13 can be considered a proximity area. For example, the coverage area of the wireless access point 13 to which the terminal device 14 is connected, as well as the coverage areas of other wireless access points 13 adjacent to that wireless access point 13, can be considered proximity areas. In such an operation, the server device 11 stores the configuration information of each wireless access point 13, and based on the AP number written in the audio data packet received from the terminal device 14, the coverage area of the wireless access point 13 identified by the AP number and the coverage areas of the wireless access points 13 adjacent to that wireless access point can be considered proximity areas.

In the above embodiment, the location of the terminal device 14 and the division of the partial communication area and the adjacent area are performed based on the coverage area of the wireless access point 13. However, the present invention is not limited to this. For example, the terminal device 14 may be equipped with a GPS receiver and the GPS coordinates may be used as the location information of the terminal device 14. Furthermore, the partial communication area may be divided according to the floor or room of a building within the coverage area.

Alternatively, the terminal device 14 can be allowed to perform area-specific communication, allowing the user to specify a desired area. In area-specific communication, multiple partial communication areas can be specified. In such an operation, multiple area numbers (AP numbers) can be written into the area information of the audio data packet.

Furthermore, in the above-described embodiment, an inactive terminal device is excluded from the communication session as an excluded terminal device. However, the terminal device may be allowed to participate in the communication session midway when the terminal device becomes active.

In the above embodiment, a communication session is established in response to a call audio packet transmitted from the terminal device 14. However, the trigger for establishing a communication session is not limited thereto. For example, an administrator may operate the hybrid table 303 from the management device 12 to establish and cancel a communication session.

Explanation of symbols

11 Server device (relay device)

12 Management Device

13 Wireless Access Points

14 Terminal Devices

20 Control unit (of terminal device)

30 Control unit (of the server device)

40 Control unit (of management device)

32 Network Communications Department

220 PTT (Push to Talk) switch

301 Terminal Form

302 Group Table

303 Hybrid Table

304 Zone Table

Claims (28)

1. A relay device comprising: a network communication unit for communicating with a plurality of terminal devices via a communication network including a wireless network; a control unit that controls communication of audio signals between the relay device and the terminal device; and Storage Department, The relay device is characterized in that The wireless network includes a plurality of access points and has a communication area obtained by synthesizing coverage areas of the access points. The storage unit includes: an area table storing a plurality of partial communication areas obtained by dividing the communication area into coverage areas of one or more access points; a terminal table storing location information indicating the coverage area of an access point in which a terminal device is located; and a group table storing, for each group, a group number and a terminal number of each terminal device belonging to the group. When a call is issued from a calling terminal device, which is one of the terminal devices, specifying the partial communication area, namely the designated partial communication area, and the designated group, which is one of the groups, the control unit Referencing the terminal table to determine which access point coverage area the calling terminal device is located in, and referring to the area table to determine which partial communication area the calling terminal device is located in, Refer to the group table to determine other terminal devices belonging to the designated group, For each terminal device belonging to the designated group, the terminal table and the area table are referred to determine whether the terminal device is located in the same partial communication area as the calling terminal device. A communication session is established in which terminal devices belonging to the designated group and located in the designated partial communication area participate, and a relay process is performed to forward a sound signal received from the terminal device participating in the communication session to other terminal devices participating in the communication session. 2. The relay device according to claim 1, wherein: The call specifying the partial communication area is a call specifying the partial communication area in which the calling terminal device is located. 3. The relay device according to claim 1, wherein: When a terminal device located outside the designated partial communication area moves and enters the designated partial communication area, the control unit causes the terminal device to participate in the communication session. 4. The relay device according to claim 1, wherein: The storage unit stores information indicating which terminal devices belong to a preset existing group. When the calling terminal device issues a call specifying the partial communication area and the existing group, the control unit establishes a communication session involving the calling terminal device and a terminal device located in the specified partial communication area and belonging to the specified existing group. 5. The relay device according to claim 4, wherein: When a terminal device located outside the designated partial communication area and belonging to the designated existing group moves and enters the designated partial communication area, the control unit causes the terminal device to participate in the communication session. 6. The relay device according to claim 1, wherein: When a terminal device participating in the communication session moves outside the designated partial communication area, the control unit excludes the terminal device from the communication session. 7. The relay device according to claim 1, wherein: The communication network has a plurality of wireless access points, Each terminal device is connected to the communication network via any wireless access point. Each of the partial communication areas is respectively composed of coverage areas of one or more wireless access points. The storage unit stores information indicating which wireless access point each terminal device is connected to as the location information. The call made by the calling terminal device and specifying the partial communication area is a call specifying any one of the wireless access points. 8. The relay device according to claim 7, wherein: The control unit receives information on the connected wireless access point from the terminal device periodically or at a predetermined timing, and updates the position information stored in the storage unit. 9. A voice communication system comprising a relay device and a plurality of terminal devices each connected to a communication network, characterized in that: The relay device comprises: a network communication unit for communicating with the plurality of terminal devices via the communication network including a wireless network; a control unit that controls communication of audio signals between the relay device and the terminal device; and Storage Department, The wireless network includes a plurality of access points and has a communication area obtained by synthesizing coverage areas of the access points. The storage unit includes: an area table storing a plurality of partial communication areas obtained by dividing the communication area into coverage areas of one or more access points; a terminal table storing location information indicating the coverage area of an access point in which a terminal device is located; and a group table storing, for each group, a group number and a terminal number of each terminal device belonging to the group. When a call is issued from a calling terminal device, which is one of the terminal devices, specifying the partial communication area, namely the designated partial communication area, and the designated group, which is one of the groups, the control unit Referencing the terminal table to determine which access point coverage area the calling terminal device is located in, and referring to the area table to determine which partial communication area the calling terminal device is located in, Refer to the group table to determine other terminal devices belonging to the designated group, For each terminal device belonging to the designated group, the terminal table and the area table are referred to determine whether the terminal device is located in the same partial communication area as the calling terminal device. The control unit establishes a communication session in which terminal devices belonging to the designated group and located in the designated partial communication area participate, and performs relay processing for forwarding a sound signal received from a terminal device participating in the communication session to other terminal devices participating in the communication session. The terminal device comprises: a terminal network communication unit for communicating with the relay device via the communication network; A location information acquisition unit, which acquires its own location information; a location information updating unit, configured to send the acquired location information to the relay device; and The calling unit sends a call specifying any partial communication area to the relay device according to a specific operation of the user. 10. The voice communication system according to claim 9, characterized in that: The communication network includes multiple wireless access points, The plurality of terminal devices are connected to the communication network via any wireless access point, The control unit of the relay device divides the communication area into each coverage area of one or more wireless access points to set the partial communication area. The terminal network communication unit communicates with the relay device via any one of the wireless access points. The position information acquisition unit acquires identification information of the wireless access point communicating with the own device, The location information updating unit sends the acquired identification information of the wireless access point as the own location information to the relay device. The calling unit sends a call specifying any wireless access point to the relay device. 11. The voice communication system according to claim 10, characterized in that: The calling unit sends a call specifying the wireless access point to which the calling unit is connected to the relay device. 12. The voice communication system according to claim 9, characterized in that The terminal device also has a push-to-talk circuit. The terminal network communication unit transmits a voice signal input from a microphone to the relay device while the push-to-talk circuit is connected, and receives a voice signal transmitted from the relay device regardless of whether the push-to-talk circuit is connected or disconnected. 13. A method for relaying a sound signal, comprising: relaying the sound signal using a relay device having a network communication unit for communicating with a terminal device via a wireless network having a plurality of access points and having a communication area obtained by combining coverage areas of the access points; and a storage unit for storing location information of the terminal device. The method for relaying a sound signal is characterized by comprising: In a first step, an area table, a terminal table, and a group table are stored in the storage unit, wherein the area table stores a plurality of partial communication areas obtained by dividing the communication area into coverage areas of one or more access points, the terminal table stores location information indicating the coverage area of an access point in which a terminal device is located, and the group table stores, for each group, a group number and a terminal number of each terminal device belonging to the group. A second step includes, when a call is issued from a calling terminal device that is one of the terminal devices, specifying the partial communication area, i.e., the specified partial communication area, and one of the groups, i.e., the specified group, referring to the terminal table to determine the coverage area of the access point in which the calling terminal device is located, referring to the area table to determine the partial communication area in which the calling terminal device is located, referring to the group table to determine other terminal devices belonging to the specified group, and for each terminal device belonging to the specified group, referring to the terminal table and the area table to determine whether it is located in the same partial communication area as the calling terminal device, and establishing a communication session in which the terminal devices belonging to the specified group and located in the specified partial communication area participate; and In a third step, the relay device forwards the audio signal received from the terminal device participating in the communication session to other terminal devices participating in the communication session. 14. The method for relaying a sound signal according to claim 13, wherein: In the second step, a call specifying a portion of the communication area where the calling terminal device is located is received. 15. The method for relaying a sound signal according to claim 13, wherein: The audio signal relay method further includes a fourth step of causing the relay device to cause a terminal device located outside the designated partial communication area to participate in the communication session when the terminal device moves into the designated partial communication area. 16. The method for relaying a sound signal according to claim 13, wherein: The storage unit further stores information indicating which terminal devices belong to a pre-set existing group. In the second step, when a call is made from the calling terminal device specifying the partial communication area and the existing group, a communication session is established between the calling terminal device and terminal devices located in the specified partial communication area and belonging to the specified existing group. 17. The method for relaying a sound signal according to claim 16, characterized in that: The method for relaying a sound signal further includes a fourth step of causing the relay device to cause a terminal device located outside the designated partial communication area and belonging to the designated original group to participate in the communication session when the terminal device moves into the designated partial communication area. 18. The method for relaying a sound signal according to claim 13, wherein: The audio signal relay method further includes a fifth step of excluding, by the relay device, the terminal device from the communication session when the terminal device participating in the communication session moves outside the designated partial communication area. 19. The method for relaying a sound signal according to claim 13, wherein: The storage unit stores information indicating which wireless access point each terminal device is connected to as the location information. In the second step, a call specifying any one of the wireless access points is received as a call specifying the partial communication area. 20. The method for relaying a sound signal according to claim 19, wherein: The method for relaying a sound signal further includes a sixth step in which the relay device receives information on a connected wireless access point from the terminal device periodically or at a predetermined time, and updates the position information stored in the storage unit. 21. A recording medium recording a computer program that causes a control unit of a relay device including a network communication unit that communicates with a terminal device via a wireless network having a plurality of access points and a communication area obtained by combining coverage areas of the access points, and a storage unit that stores location information of the terminal device to function as the following means: The first unit stores an area table, a terminal table, and a group table in the storage unit, wherein the area table stores a plurality of partial communication areas obtained by dividing the communication area into coverage areas of one or more access points, the terminal table stores location information indicating the coverage area of an access point in which a terminal device is located, and the group table stores, for each group, a group number and a terminal number of each terminal device belonging to the group. The second unit, when a call is issued from a calling terminal device that is one of the terminal devices and specifies the partial communication area, i.e., the designated partial communication area, and one of the groups, i.e., the designated group, refers to the terminal table to determine the coverage area of the access point in which the calling terminal device is located, refers to the area table to determine the partial communication area in which the calling terminal device is located, refers to the group table to determine other terminal devices belonging to the designated group, and for each terminal device belonging to the designated group, refers to the terminal table and the area table to determine whether it is located in the same partial communication area as the calling terminal device, and establishes a communication session in which the terminal devices belonging to the designated group and located in the designated partial communication area participate; and The third unit transfers a voice signal received from a terminal device participating in the communication session to other terminal devices participating in the communication session. 22. The recording medium according to claim 21, wherein The second unit receives a call specifying a partial communication area where the calling terminal device is located. 23. The recording medium according to claim 21, wherein The program causes the control unit to further function as fourth means for causing a terminal device located outside the designated partial communication area to participate in the communication session when the terminal device moves into the designated partial communication area. 24. The recording medium according to claim 21, wherein The storage unit further stores information indicating which terminal devices belong to a pre-set existing group. When a call is made from the calling terminal device specifying the partial communication area and the existing group, the second unit establishes a communication session between the calling terminal device and a terminal device located in the specified partial communication area and belonging to the specified existing group. 25. The recording medium according to claim 24, wherein The program causes the control unit to further function as a fourth unit that causes a terminal device located outside the designated partial communication area and belonging to the designated existing group to participate in the communication session when the terminal device moves into the designated partial communication area. 26. The recording medium according to claim 21, wherein The program causes the control unit to further function as fifth means for excluding a terminal device participating in the communication session from the communication session when the terminal device moves outside the designated partial communication area. 27. The recording medium according to claim 21, wherein The storage unit stores information indicating which wireless access point each terminal device is connected to as the location information. The second unit receives a call specifying any wireless access point as a call specifying the partial communication area. 28. The recording medium according to claim 27, wherein The program causes the control unit to further function as a sixth unit that receives information on the connected wireless access point from the terminal device periodically or at a predetermined timing and updates the position information stored in the storage unit.