JP2008277981A - Owner changing method and poc client in group communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a group communication system capable of preventing a group from breaking up when the terminal device of an owner moves out of a communication zone. <P>SOLUTION: The group communication system comprises a PoC client 1a as the owner, PoC clients 1b to 1d as members, and a server device 2, and the PoC client 1a as the owner stores a state list wherein a prediction result showing whether the terminal device moves out of the communication zone is described, and generates as a list change request a request for changing the owner to one of the PoC clients 1b to 1d as members when the prediction result showing that the terminal device moves out of the communication zone is described. The server device 2 stores a member list wherein the owner and members are described, and rewrites the owner in the member list to one of the PoC clients 1b to 1d as the members when receiving the list change request. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a group call system that enables a call within a group to which a plurality of members and two or more members belong.

Conventional group call systems include the following. First, a user (sender) selects a member list and presses a PTT (Push To Talk) button of a PoC (Push-to-talk over Cellular) client. In response to this operation, the PoC client (hereinafter referred to as a terminal device) transmits a group call setup request to the control device. The control device ends the process of setting up the group call by sending a call announcement to the members in the member list including the caller. Thereafter, a call can be made within a group in which the caller is a group owner (hereinafter simply referred to as an owner) (see, for example, Patent Document 1).
JP 2005-528818 A

  In the conventional group call system, the caller continues to be the owner until the end of the group call, and keeps the group maintenance right. Therefore, if the owner terminal device goes out of the communication range, the group maintenance right disappears and the group is canceled. As a result, the group call ends. In other words, even if the remaining member terminal devices exist within the communication range, the group call cannot be continued only by the remaining members.

  Therefore, an object of the present invention is to provide a group call system capable of preventing group cancellation caused by movement of an owner terminal device out of a communication range.

  To achieve the above object, according to one aspect of the present invention, in order to perform a group call, a first PoC client as a group owner and a second PoC client as a group member are connected via a server device. An owner change method used in a communicating group call system, which is executed by a first PoC client and is used to change a group owner to a second PoC client based on a prediction result indicating that the communication is out of a communication range. A request generation step for generating a list change request, a transmission step executed by the first PoC client, and a list change request generated by the request generation step is sent to the server device. In response to receiving the list change request sent in step, at least the current group Owner access to the described member list, including a group owner, and a rewriting unit for rewriting into the second PoC client.

  According to the above aspect, when the first PoC client is about to go out of the communication range, a list change request for changing the owner to the second PoC client is transmitted to the server device. In response to the list change request, the server device rewrites the owner from the first PoC client to the second PoC client. Therefore, the group call is subsequently performed under the new owner. This makes it possible to prevent the group from being eliminated due to the movement of the owner's PoC client outside the communication range.

1. Configuration of group communication system 1-1. Overall Configuration FIG. 1 is a block diagram showing an overall configuration of a group communication system (hereinafter simply referred to as a system) according to a first embodiment of the present invention. As shown in FIG. 1, a plurality of PoC (Push to talk over Cellular) clients 1 and a server device 2 can communicate with each other via a communication network 3 such as an IP (Internet Protocol) network. Connected.
1-2. Configuration of PoC Client 1 First, the configuration of the PoC client 1 will be described first.

  Each PoC client 1 includes a terminal device 4 and a mobile phone 5.

  Each terminal device 4 is, for example, an in-vehicle navigation device or an in-vehicle AV device. Each terminal device 4 is connected to the mobile phone 5 by a wireless link or a wired transmission path. Each mobile phone 5 receives various information from the terminal device 4 connected to itself and transmits it to the server device 2, receives various information from the server device 2, and transmits it to the terminal device 4.

  In FIG. 1, PoC clients 1 a to 1 d are illustrated as PoC clients 1. The PoC client 1a includes a terminal device 4a and a mobile phone 5a, and the PoC clients 1b to 1d include terminal devices 4b to 4d and mobile phones 5b to 5d. The above PoC clients 1a to 1d belong to the same group, and the users of the PoC clients 1a to 1d make a voice call with each other within the group.

  In addition, any PoC client 1 belonging to the group becomes the owner of the group, and the rest become members of the group. The owner is the PoC client 1 that has transmitted the group call setup request, and the member is the PoC client 1 that is requested to join the group by the caller. In the example of FIG. 1, the PoC client 1a is the owner, and the PoC clients 1b to 1d are members.

  Each terminal device 4 is connected to a hands-free device (not shown) in which, for example, an earphone and a microphone are set so that the user becomes hands-free during a voice call.

  Next, a detailed configuration of each terminal device 4 will be described. As shown in FIG. 1, the terminal device 4 includes a communication interface 41, a locator 42, an area storage unit 43, a state storage unit 44, and a processing unit 45.

  The communication interface 41 transmits various types of information from the processing unit 45 to the mobile phone 5a and receives various types of information from the mobile phone 5a.

  The locator 42 is, for example, a GPS (Global Positioning System) receiver, calculates the current position of the terminal device 4, and sends current position information indicating the calculated current position to the processing unit 45. The locator 42 may further include a so-called self-contained navigation sensor.

  The area storage unit 43 is provided in a storage device including a readable storage medium, and an area (hereinafter referred to as “out of communication range”) in which the mobile phone 5 is known to be unable to communicate is a combination of latitude and longitude, for example. Stores area information to be identified. Examples outside the communication range are in tunnels, indoor parking lots and mountainous areas. Alternatively, the area information may alternatively specify an area (hereinafter referred to as a communication area) that is previously known that the mobile phone 5 can communicate.

  The state storage unit 44 is provided in a storage device including a writable storage medium, and stores a state table 441 for a group. Here, FIG. 2 is a schematic diagram illustrating the state table 441. In FIG. 2, the status table 441 describes the identification information of all PoC clients 1 belonging to the group. The state table 441 further describes a communication state prediction result in association with the identifier of the own PoC client 1. However, the communication state (prediction result) of other PoC clients 1 is not described. The communication state (prediction result) is derived by the processing unit 45 described later, and indicates a prediction result as to whether or not the own PoC client 1 can communicate after a predetermined time. In the present embodiment, “communication enabled” and “communication disabled” are defined as communication states (predicted results).

  In the example of FIG. 2, identification information “a”, “b”, “c”, and “d” is described as identification information of the PoC clients 1a, 1b, 1c, and 1d belonging to the same group. If it is assumed that the state table 441 in FIG. 2 is that of the PoC client 1a, the state table 441 describes the communication state (predicted result) of the PoC client 1a, for example, “communication impossible”.

The processing unit 45 is constituted by a CPU, for example, and is connected to a ROM and a RAM (both not shown). The processing unit 45 executes the computer program stored in the ROM using the RAM. Detailed processing contents of the processing unit 45 will be described later.
1-3. Configuration of Server Device 2 Next, the server device 2 of FIG. 1 will be described. The server device 2 is, for example, a PoC server, and includes at least a communication unit 21, a list storage unit 22, and a processing unit 23.

  The communication unit 21 receives various information from each mobile phone 5 via the communication network 3 and transmits various information to the mobile phone 5.

  The list storage unit 22 includes a data rewritable storage device, and stores a group member list 221. Here, FIG. 3 is a schematic diagram illustrating the member list 221. In FIG. 3, the member list 221 describes the identification information of the PoC client 1 as the owner and the identification information of the member PoC client 1 in the group. In the example of FIG. 3, “owner” is described in a form linked to the identification information “a”, and “member” is described in a form linked to the identification information “b” to “d”.

The processing unit 23 includes, for example, a CPU, and executes a computer program stored in a ROM (not shown) using a RAM (not shown). The processing content of the processing unit 23 will be described later.
2. Processing in Group Communication System Next, processing in each part of the system will be described. However, since the process at the time of setting a group call and the process itself related to the voice call are the same as those of the known technique or the known technique, the description thereof is omitted. Only the group owner switching process unique to this embodiment will be described below.
2-1. Process of Owner PoC Client 1 First, the process of the owner PoC client 1 (hereinafter referred to as owner client 1) will be described with reference to FIG. When the group call setting is completed, the processing unit 45 in the owner client 1 indicates identification information of all PoC clients 1 in the group, which PoC client 1 is “owner”, and which PoC client 1 is “member”. Information is received from the server device 2, and the state table 441 describing the received information is stored in the state storage unit 44 (step S301).

  After completion of step S301, for example, every time the current position information from the locator 42 is input, step S302 and subsequent steps are executed. In addition, step S302 and the subsequent steps may be periodically executed at predetermined time intervals.

  In step S <b> 302, the processing unit 45 acquires current position information from the locator 42 and reads area information from the area storage unit 43. Further, the processing unit 45 obtains a vehicle speed pulse from a vehicle speed pulse generator (not shown) connected to the owner client 1, and derives the current speed of the vehicle based on the vehicle speed pulse (step S302).

  Next, the processing unit 45 uses the information obtained in step S302 to calculate a time predicted to reach from the current position to the outside of the communication range (hereinafter referred to as arrival time) (step S303). Specifically, the distance from the current position from the locator 42 to the outside of the communication area defined by the area information is divided by the current speed, and the quotient is the arrival time.

  Thereafter, the processing unit 45 determines whether or not the calculated arrival time is equal to or shorter than a predetermined time (hereinafter referred to as a threshold value) (step S304). The threshold is selected based on, for example, the expiration time of one floor assigned by PoC floor control. If the expiration time is 30 seconds, for example, the threshold is selected to be 1 minute, for example.

  When it is determined Yes in step S304, the processing unit 45 regards that the vehicle is out of the communication range within a short time, that is, within the time indicated by the threshold value, and stores “not communicable” as the communication state (predicted result). The data is written in the status table 441 (see FIG. 2) of the unit 44 (step S305). On the contrary, in the case of No, “communication permitted” is written (step S306).

  Here, FIG. 2 illustrates a case where the PoC client 1 a as the owner client 1 writes “communication impossible” in the state table 441. Since the processing unit 45 cannot know the communication state (prediction result) of the PoC client 1 other than itself, the communication state of the other PoC client 1 is not written in the state table 441.

  After step S305 or S306, the processing unit 45 determines whether or not the communication state (prediction result) is currently “communication impossible” (step S307). When determining No, the processing unit 45 returns to step S302 and waits until the next execution timing of step S302.

  On the other hand, when it is determined Yes in step S307, the processing unit 45 determines whether or not it is currently “owner” based on the contents of the state table 441 (step S308). When it is determined No, there is no need to change the owner, so the processing unit 45 returns to Step S302 and waits for the next execution timing.

  If the arrival time is equal to or less than the threshold value in step S304 described above, the process transitions to step S305. Instead, the distance from the current position of the vehicle to the outside of the communication range is equal to or less than a predetermined reference value. Step S305 may be executed. Further, when the terminal device 4 is an in-vehicle navigation device, the processing unit 45 can obtain route information from the departure place to the destination. In this case, it is possible to calculate the distance from the current position to the outside of the communication area when the vehicle travels according to the route information. Therefore, in step S304, when this road is equal to or smaller than the threshold value, the process may be shifted to step S305.

  When it is determined Yes in step S308, the processing unit 45 executes an owner change process (step S309). This step S309 includes steps S310 to S316 as shown in FIG.

  First, in step S310, the processing unit 45 of the owner client 1 obtains the right to speak normally used for group calls in order to exchange control data for changing owners. After acquiring the floor, the processing unit 45 accesses the state storage unit 44 and selects one of the unidentified ones from the PoC client 1 (hereinafter referred to as member client 1) that is currently described as a member. Are selected (step S310).

  Next, the processing unit 45 generates control data called an owner change request (step S311). As shown in FIG. 5, the owner change request includes an identifier, a destination, a message type, and a data portion.

  In FIG. 5, the identifier indicates control data. The destination is the identification information selected in step S310. The message type indicates that this control data is an owner change request. The data portion is identification information of the current owner client 1 in the case of an owner change request. Such an owner change request is control data for requesting an owner change to the member client 1 having the destination identification information.

  The owner change request as described above is stored in the payload portion of the message exchanged during the group call by PoC, as shown in FIG. Such a message is sent from the processing unit 45 to the communication network 3 via the mobile phone 5 (step S312). Thereafter, the processing unit 45 releases the right to speak.

  Although details will be described later, after the message including the owner change request is transmitted, the owner client 1 receives an affirmative response or a negative response.

  The positive response is control data indicating that the member client 1 has accepted the owner change request, and includes an identifier, a destination, a message type, and a data portion as shown in FIG.

  In FIG. 6, the identifier indicates control data, similar to the owner change request. The destination is the identification information of the current owner client 1, that is, the identification information set in the data portion of the owner change request. The message type indicates that this control data is an acknowledgment. The data part is identification information set as the destination of the PoC client 1 that is the transmission source of this acknowledgment, that is, the owner change request.

  The negative response is control data indicating that the member client 1 has rejected the owner change request, and includes an identifier, a destination, a message type, and a data portion as shown in FIG.

  Here, in the negative response, the identifier, the destination, and the data portion are the same as those in the positive response, and thus the description thereof is omitted. The message type indicates that this control data is a negative response.

  Reference is again made to FIG. After step S312, the processing unit 45 of the owner client 1 receives either an affirmative response or a negative response as a response to the owner change request via the mobile phone 5 and the communication interface 41.

  However, an affirmative response and a negative response are also set in the payload portion of the message in the same manner as the owner change request. Therefore, the processing unit 45 first checks the identifier (see FIG. 5) of the payload portion of the message and determines whether or not the identifier indicates control data. Next, it is determined whether the message type of the payload portion is a positive response or a negative response.

  The processing unit 45 checks the message type to determine whether or not the current received message is a negative response (step S313), and then determines whether or not the current received message is an affirmative response (step S314). . If it is determined No in either step S313 or S314, the process returns to step S310. On the other hand, if it is determined Yes in step S314, it is assumed that the member client 1 that has transmitted the acknowledgment has accepted the owner change, obtains the right to speak, and generates control data called a list change request (step S315). .

  The list change request is control data for requesting the server apparatus 2 to change the member client 1 that has transmitted the acknowledgment to a new owner, and as shown in FIG. 8, an identifier, a destination, a message type, Data portion.

  In FIG. 8, the identifier indicates control data. The destination is identification information assigned in advance to the server device 2. The message type indicates that this control data is a list change request. In the case of a list change request, the data portion is identification information of a new owner client 1, that is, identification information of an acknowledgment transmission source.

  The list change request as described above is also stored in the payload portion of the message, like other control data, and then sent to the communication network 3 (step S316). Thereafter, the processing unit 45 releases the right to speak.

  Although details will be described later, after the transmission of the message including the list change request, the owner client 1 receives a completion notification.

  The completion notification is control data for notifying the current owner client 1 that the server device 2 has updated the member list 221, and, as shown in FIG. 9, an identifier, a destination, a message type, and a data part are Including.

  In FIG. 9, the identifier indicates control data. The destination is identification information of the current owner client 1. The message type indicates that this control data is a completion notification. No data portion is set in the case of completion notification.

Reference is again made to FIG. After step S316, the processing unit 45 of the owner client 1 receives a completion notification as a response to the list change request transmitted earlier via the mobile phone 5 and the communication interface 41 (step S317). With this reception, the processing unit 45 considers that the change to the new owner has been completed, and ends the processing of FIG.
2-2. Process of Member PoC Client 1 Next, the process of the member PoC client 1 (member client 1) will be described with reference to FIG. When the setting of the group call is completed, the processing unit 45 in each member client 1 performs the same processing as steps S301 to S306 executed by the owner client 1 (steps S401 to S406).

  After step S406, the processing unit 45 determines whether an owner change request addressed to itself has arrived (step S407). Hereinafter, detailed processing of step S407 will be described. As described above, the owner change request is normally set in the payload portion of a message used in a voice call. Therefore, the processing unit 45 first checks the payload portion of the message to determine whether an identifier (see FIG. 5) indicating control data is set. Next, it is determined whether or not the message type of the payload portion is an owner change request, and then it is determined whether or not the identifier set at the destination is own. When the above three determination results are Yes, the determination result of Step S407 is Yes, and when any one is No, the determination result of Step S407 is No.

  If it is determined No in step S407, the processing unit 45 returns to step S402 and waits until the next execution timing of step S402 comes.

  On the other hand, when it is determined Yes in step S407, the processing unit 45 executes an owner change process (step S408). This step S408 includes steps S409 to S413 as shown in FIG.

  In the owner change process, first, the processing unit 45 determines whether or not the current communication state (prediction result) is “communication enabled” (step S409).

  When determining Yes, the processing unit 45 generates the above-described acknowledgment (see FIG. 6) (step S410), stores the generated acknowledgment in the payload portion of the message exchanged during the voice call, and performs communication. The data is sent to the communication network 3 via the interface 41 and the mobile phone 5 (step S411).

  On the other hand, when it is determined No in step S409, the processing unit 45 generates the above-described negative response (FIG. 7) (step S412) and sends it to the communication network 3 in the same manner as the positive response (step S413).

When the above step S411 or S413 ends, the owner change process in the member client 1 ends.
2-3. Processing of Server Device 2 Next, processing of the server device 2 will be described with reference to FIG. During the owner change process, the server apparatus 2 receives via the communication network 3 a message in which the list change request includes the list change request from the owner client 1 (see FIG. 8) in the payload portion. In the server device 2, the processing unit 23 receives a message via the communication unit 21, and first determines whether a list change request has arrived (step S1101). Specifically, first, it is determined whether or not there is an identifier (see FIG. 8) indicating control data in the payload portion of the message, and then whether or not the message type indicates a list change request. When the above two determination results are Yes, the determination result of Step S1101 is Yes, and when any one is No, the determination result of Step S1101 is No.

  If it is determined No in step S1101, the processing unit 23 determines that the received message is not a list change request and ends the owner change process.

  On the other hand, when the determination is Yes, the processing unit 23 rewrites “owner” associated with the identification information of the current owner client 1 into “member” in the member list 221 in the list storage unit 22 (step S1102). ). Further, the processing unit 23 extracts the identification information of the new owner client 1 set in the data portion of the list change request (step S1103), and sets the “member” associated with the identification information extracted in step S1103 to “ “Owner” is rewritten (step S1104).

When the processing in step S1104 is completed, the processing unit 23 acquires the right to speak, generates a completion notification (see FIG. 9) (step S1105), and sends it to the communication network 3 via the communication unit 21 (step S1106). ). Thereafter, the right to speak is released, and the owner change process in the server device 2 is thereby terminated.
3. Owner Change Sequence Next, an example of control data exchange in the owner change will be described with reference to FIG.
It is assumed that the owner client 1 is the PoC client 1a and the member client 1 is the PoC clients 1b to 1d at the start of transmission / reception of control data in FIG. Further, it is assumed that the current communication state (prediction result) of the owner client 1a is “communication impossible” as shown in the state table 441 in FIG. 2 (see FIG. 2).

  Under the above assumption, the owner client 1a selects one piece of identification information of the unselected member client 1 in step S310 in FIG. 4 when the owner change process in FIG. 4 is executed. This time, it is assumed that the identification information “b” of the member client 1b is selected.

  Thereafter, in step S311 of FIG. 4, the owner client 1a generates an owner change request (see FIG. 5) set with the selected identification information “b” as the destination, and includes the generated owner change request in the payload portion. The message is sent to the communication network 3 in step S312 of FIG.

  The above message (owner change request) reaches all the member clients 1b to 1d via the communication network 3 or the like. When the member clients 1b to 1d perform the process of FIG. 10, as shown in step S501 of FIG. 12, the member client 1b assumes that this message (owner change request) is addressed to itself, and in step S409 of FIG. Make a decision.

  Here, it is assumed that “not communicable” is described in the state table 441 of the member client 1b as the communication state (prediction result). In this case, the member client 1b generates a negative response shown in FIG. 7 in step S412 of FIG. 10, and a message including the generated negative response in the payload portion is sent to the communication network 3 in step S413. .

  The message (negative response) reaches the owner client 1a via the communication network 3 or the like as shown in step S502 of FIG. When the owner client 1a executes Step S313 in FIG. 4 in response to the reception of the message, the owner client 1a determines No, and therefore executes Step S310 in FIG. 4 again. In this step S310, it is assumed that the identification information “c” of the member client 5c is selected.

  After that, the owner client 1a executes steps S311 and S312 in FIG. 4 to generate an owner change request (see FIG. 5) in which the selected identification information “c” is set as a destination and send it to the communication network 3. .

  In response to the current message (owner change request), the member client 1c determines in step S409 in FIG. Here, it is assumed that “communication permitted” is described as the communication state (prediction result) in the state table 441 of the member client 1c. Under this assumption, the member client 1b generates an acknowledgment shown in FIG. 6 in step S410, and sends the generated acknowledgment (message) to the communication network 3 in step S411.

  The message (acknowledgment) reaches the owner client 1a as shown in step S504 in FIG. When the owner client 1a executes step S314 in FIG. 4 in response to the reception of the message, the owner client 1a determines Yes. Therefore, the owner client 1a generates a list change request in step S315, and the list change request in the payload portion in step S316. A message including the message is transmitted to the communication network 3.

  The message (list change request) reaches the server apparatus 2 via the communication network 3 or the like as shown in step S505 in FIG. In response to receiving the list change request, the server apparatus 2 performs the process of FIG. At that time, as shown in FIG. 13, the server device 2 rewrites “owner” linked to the identification information “a” in the member list 221 to “member” in step S1102, and in step S1103, the identification information “ Rewrite “member” associated with “c” to “owner”. As a result, the group owner is changed from the PoC client 1a to the PoC client 1c.

  As described above, according to the present system, when the communication state of the owner client 1 becomes “communication impossible”, the owner change request is individually transmitted to the member client 1. When the owner client 1 a receives an affirmative response from the member client 1 in response to the owner change request, the owner client 1 a transmits a list change request to the server device 2. In response to the list change request, the server device 2 accesses the member list 221 and sets a new owner. Thereafter, the group call is performed under the new owner. This makes it possible to prevent the group from being eliminated due to the movement of the owner client 1 out of the communication range.

  When the client 1 is mounted on a vehicle, the client 1 often goes out of the communication area such as when passing through a tunnel, and the group call is interrupted each time. However, it is possible to prevent such a group call from being interrupted by changing the owner as in the present embodiment.

  As described above, in this system, the caller does not necessarily remain the owner until the end of the group call, and the owner client may be changed to another client according to the current communication state prediction. . Therefore, even when there is a high probability that the current owner client will be out of the communication range, the group maintenance right is handed over to another client, so that the group can be prevented from being canceled.

  In the above embodiment, the arrival time to the outside of the communication range is calculated in step S303 using the current position acquired from the locator 42 and the area information read from the area storage unit 43. However, the present invention is not limited to this, and each terminal device 4 may calculate the arrival time as follows. That is, each terminal device 4 stores, for example, map data representing a road network. In this map data, information indicating a location that is known in advance as being incapable of communication in this road network is different from the area information. Suppose that it is added as an example. In this case, each terminal device 4 may calculate the arrival time from the current position to the outside of the communication area using the map data.

  In the embodiment described above, the processing unit 45 writes “communication impossible” as the communication state (prediction result) in the state table 441 when the calculated arrival time is equal to or less than the threshold value in step S304. In addition, the communication state (prediction result) may be written by the following method. That is, the terminal device 4 is not configured to be connectable to the mobile phone 5 but may be provided internally as a mobile phone unit 46 having the function of the mobile phone 5 as shown in FIG. In this case, the processing unit 45 can obtain information (reception field strength or bit error rate) indicating the reception status of radio waves from the mobile phone unit 46. In this case, the processing unit 45 may write the communication state (prediction result) in the state table 441 as “communication impossible”, for example, when the received electric field strength or the bit error rate falls below a predetermined threshold.

  In the above embodiment, as shown in step S501 of FIG. 12, for example, the owner client 1a transmits an owner change request to one member client 1. However, the present invention is not limited to this. May be broadcast to all member clients 1.

  In the above embodiment, each client 1 needs to acquire the right to speak before sending control data such as an owner change request. Further, from the viewpoint of maintaining the group call, it is preferable that the server device 2 gives the speaking right preferentially to the client 1 that has sent such a request for speaking right.

  As mentioned above, although this invention was demonstrated in detail, the said description is an illustration in all the meanings, and is not restrictive. It will be understood that other modifications and variations are possible without departing from the scope of the invention.

  The group call system according to the present invention can be applied to a PoC communication system in which the effect that it is possible to prevent the group from being canceled due to the movement of the owner terminal device outside the communication range is required.

The block diagram which shows the whole structure of the group communication system which concerns on the 1st Embodiment of this invention. The schematic diagram which shows the structure of the state table 441 stored in the state storage part 44 shown in FIG. The schematic diagram which shows the structure of the member list 221 stored in the list storage part 22 shown in FIG. The flowchart which shows the processing procedure of the owner PoC client 1 Schematic diagram showing the structure of owner change request Schematic diagram showing the structure of acknowledgment Schematic diagram showing the structure of negative response Schematic diagram showing the structure of a list change request Schematic diagram showing the structure of completion notification Flow chart showing processing procedure of member PoC client 1 The flowchart which shows the process sequence of the server apparatus 2 Data flow diagram for changing owners Schematic diagram showing contents before and after rewriting member list 221 The block diagram which shows the alternative structure of the terminal device 4 shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PoC client 2 Server apparatus 21 Communication part 22 List storage part 221 Member list 23 Processing part 3 Communication network 4 Terminal device 41 Communication interface 42 Locator 43 Area storage part 44 Status storage part 441 Status table 45 Processing part 46 Cellular telephone part 5 Carrying phone

Claims (8)

An owner change method used in a group call system in which a first PoC client as a group owner and a second PoC client as a group member communicate via a server device in order to perform a group call,
A request generating step for generating a list change request for changing a group owner to the second PoC client based on a prediction result executed by the first PoC client and indicating that the mobile phone is out of communication range;
A sending step executed by the first PoC client and sending the list change request generated in the request generating step to the server device;
In response to reception of the list change request executed in the server device and sent in the sending step, at least the current group owner is accessed to access the member list in which the group owner is designated as the second PoC client. Owner change method, including a rewriting unit that rewrites A PoC client that makes a group call via a communication network,
A state storage unit that stores a state list in which a prediction result indicating whether or not to go out of communication range is described;
A first result of generating a list change request for changing the group owner to another PoC client when the prediction result indicating that the state storage unit is out of the communication range is stored and the owner is the group owner. A request generation unit of
A PoC client comprising: a first transmission unit that transmits a list change request generated by the first request generation unit to a server device connected to the communication network.   The PoC client according to claim 2, wherein the list change request is transmitted in a state set in a payload of a message for group call after the PoC client acquires a right to use in a group call by PoC. The PoC client
If the prediction result indicating that the state storage unit is out of the communication range is stored and the owner is the owner of the group, a second change request is generated for requesting another PoC client to change the owner. A request generation unit of
A second sending unit for sending the owner change request generated by the second request generating unit to the other PoC client via the communication network;
The said 1st request generation part produces | generates the said list change request, when the positive response with respect to the owner change request sent by the said 2nd transmission part is sent from the said another PoC client. The described PoC client.   When a negative response to the owner change request sent from the second sending unit is sent from the other PoC client, the second request generation unit requests another PoC client to change the owner. 5. The PoC client according to claim 4, which generates another owner change request.   5. The PoC client according to claim 4, wherein the owner change request is transmitted in a state set in a payload of a message for group call after the PoC client acquires a right to use in a group call by PoC. An area storage unit for storing area information for identifying an incommunicable area;
A locator to derive the current position;
Using the vehicle speed pulse sent from the outside, the area information stored in the area storage unit, and the current position derived by the locator, generate a prediction result indicating whether or not to go out of communication range, The PoC client according to claim 1, further comprising a processing unit that writes in a state list of the state storage unit. A mobile phone unit that generates information indicating the reception status of radio waves;
The information processing apparatus according to claim 1, further comprising: a processing unit that generates a prediction result indicating whether or not to go out of a communication range using the information generated by the mobile phone unit and writes the prediction result in a state list of the state storage unit. PoC client.

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