JP4994594B2 - PTT call system - Google Patents

Description

  The present invention relates to a push-to-talk (PTT) call system, and more particularly to a technique for displaying a call partner on a display unit during a PTT call.

  A push-to-talk call (hereinafter referred to as “PTT call”) is a call that is performed between a plurality of mobile phones using a network such as the Internet. In a PTT call, each mobile phone that performs a PTT call Log in to a server connected to the network and mediate the PTT call, and voice transmission / reception is performed between the mobile phones via the logged-in server, and the display unit of each mobile phone shows the other party of the PTT call An icon or the like is displayed (see Patent Document 1).

Thereby, the user of the PTT call can talk with a plurality of other parties at the same time while recognizing the other parties participating in the call via the display unit of the mobile phone.
Special Table 2002-536928

  However, if some of the other parties are unable to continue the call during the PTT call, for example, the other party ends the call halfway, or the communication state of the other party's mobile phone changes, resulting in an out-of-service state. In such a case, in the above prior art, other call participants cannot know this, and even if the other party thinks that the other party is continuing the call, The other party will have a problem that the message is not transmitted.

  In view of the above-described problems, the present invention can be applied to a case where the other party's mobile phone participating in a call cannot continue the PTT call during the PTT call. It is an object of the present invention to provide a PTT call system that can notify a mobile phone of a call participant.

  In order to solve the above problems, the present invention provides a plurality of mobile phones having a push-to-talk (PTT) call function and having a display unit, and an intermediary server that mediates PTT calls in which each of the mobile phones can participate. The intermediary server includes a monitoring unit that monitors a change in a participation state of each mobile phone in the PTT call after the PTT call is started, and any one of the mobile phones. And a change notification means for notifying each mobile phone participating in the PTT call that the change has occurred when the participation state is changed, and participating in the PTT call Each of the mobile telephones has a configuration in which, when the notification is given, information indicating that the change has occurred is displayed on the display unit based on the notification. (Hereinafter referred to as "Configuration 1".).

  The present invention is also a mediation server that has a push-to-talk (PTT) call function and mediates a PTT call in which a plurality of mobile phones having a display unit can participate. A monitoring unit that monitors a change in the participation state of the telephone in the PTT call, and the mobile phone that is participating in the PTT call when the participation state is changed in any of the mobile phones. A change notification means for notifying that the change has occurred (hereinafter referred to as “configuration 2”) may be employed.

By providing the above configuration, the present invention can easily know even when the other party's mobile phone becomes non-participating during a PTT call. It is possible to prevent a problem that a message is not actually transmitted to the other party and later noticed.
Here, in the configuration 1 and the configuration 2, the monitoring means monitors the connection status of each mobile phone that is participating in the PTT call with the base station, and the mobile phone that is not connected to the base station. A non-connection detection means for attempting detection may be provided, and the change notification means may notify the mobile phone that is participating in the PTT call when the detection is made.

  As a result, if the other party's mobile phone is disconnected for some reason during the PTT call, other call participants can immediately know this, so it is appropriate for the communication situation. You can deal with it. For example, when the call partner is moving on a train, the call can be interrupted for a while and the call partner can wait to return to the PTT call.

  Here, in the configuration 1, each of the mobile phones has an interruption notification transmitting unit that transmits an interruption interruption notification for notifying an interruption of participation in the PTT call to the mediation server according to a user instruction, and the monitoring The means includes interruption detection means for monitoring reception of the participation interruption notification and trying to detect the participation interruption notification, and the change notification means is participating in the PTT call when the detection is made. The mobile phone may be notified that the participation has been interrupted (hereinafter referred to as “configuration 3”).

  In the configuration 2, the monitoring unit monitors reception of a participation interruption notification for notifying a participation interruption in the PTT call transmitted from any of the mobile phones participating in the PTT call, And an interruption detecting means for trying to detect the interruption of participation, and the change notification means, when the detection is made, notifies the mobile phones participating in the PTT call that the participation interruption has occurred. It is also possible to do this (hereinafter referred to as “Configuration 4”).

As a result, when a call participant interrupts a call at his / her own will during a PTT call, other call participants can immediately know the fact, and the call participant is not notified. Thus, it is possible to easily identify the range of the content of the call and to inform only the unreported part of the call to the call participant later.
Here, in the configuration 3, each of the mobile phones has a re-participation request transmission unit that transmits a re-participation request for requesting re-participation in the PTT call according to a user instruction, and the interruption detection unit includes: The re-participation is detected by receiving the re-participation request, and the change notification means notifies the re-participation of the re-participation when participating in the PTT call. It is good to make each mobile phone,
In the configuration 4, the interruption detection unit monitors reception of a re-participation notification requesting re-participation in the PTT call, which is transmitted from the mobile phone that has made the participation interruption notification, and the re-participation notification When the detection is detected, the change notification means may notify the mobile phones participating in the PTT call that the re-participation has occurred.

As a result, it is possible to immediately know that the other party who has stopped participating in the PTT call has rejoined the call, so other call participants can easily resume the conversation with the rejoined call participant. can do.
Here, in Configuration 1, the intermediary server starts the PTT call in response to a call start request from any of the mobile phones, and the monitoring unit is configured to start the PTT call at the start of the PTT call. Detection means for detecting a participation state in a PTT call, and a request for repeatedly transmitting a participation request notification for requesting participation in the PTT call to the mobile phone for a predetermined period when the mobile phone in a non-participation state is detected Each mobile phone has a response notification transmission means for transmitting a response notification to the mediation server when the participation request notification is received, and the monitoring means is configured to receive the response notification. In the middle of trying to detect the response notification, and the change notification means is participating in the PTT call when the detection is detected. Serial to the mobile phone may be able to notice that there was a way participate in the PTT call of the portable telephone of nonparticipating state (hereinafter, referred to as "Configuration 5".).

In the configuration 1, the mediation server starts the PTT call in response to a call start request from any of the mobile phones, and the monitoring unit is configured to start the PTT call of each mobile phone at the start of the PTT call. A detecting means for detecting the participation state in the call;
A request notification transmission means for transmitting a participation request notification for requesting participation in the PTT call to the address of the mobile phone when the mobile phone in a non-participating state is detected; And a response notification transmission unit that transmits a response notification to the mediation server when the participation request notification is received, and the monitoring unit monitors the reception of the response notification and detects the response notification. The mid-attendance detection means includes a change notification means, and when the detection is detected, the mobile phone that is participating in the PTT call is notified that the mobile phone that is not participating in the PTT call It may be notified that there has been (hereinafter referred to as “configuration 6”).

  In the configuration 2, the mediation server starts the PTT call in response to a call start request from any of the mobile phones, and the monitoring unit is configured to start the PTT call of each mobile phone at the start of the PTT call. Detection means for detecting a participation state in a call, and a request notification for repeatedly transmitting a participation request notification for requesting the mobile phone to participate in the PTT call for a predetermined period when the non-participating mobile phone is detected When the participation request notification is received by the transmitting unit and the mobile phone in a non-participating state, monitoring of reception of a response notification transmitted from the mobile phone and attempting to detect the response notification is performed. The change notification means, when the detection is made, the mobile phone that is participating in the PTT call is not connected to the mobile phone in a non-participating state. It is also possible that the notification that there was a halfway participation in the said PTT call of the story machine.

  In the configuration 2, the mediation server starts the PTT call in response to a call start request from any of the mobile phones, and the monitoring unit is configured to start the PTT call of each mobile phone at the start of the PTT call. Detection means for detecting a participation state in a call, and a request notification for sending a participation request notification for requesting participation in the PTT call to the address of the mobile phone when the mobile phone in a non-participating state is detected When the participation request notification is received by the transmitting unit and the mobile phone in a non-participating state, monitoring of reception of a response notification transmitted from the mobile phone and attempting to detect the response notification is performed. The change notification means, when the detection is made, the mobile phone that is participating in the PTT call is not connected to the mobile phone in a non-participating state. It is also possible that the notification that there was a halfway participation in the said PTT call of the story machine.

This makes it possible for a user who has not been able to participate in the call because the battery is out of service or the radio wave does not reach at the start of the PTT call to be able to participate in the call later. It is possible to flexibly cope with the PTT call impossible state associated with the above.
Here, in configurations 5 and 6, the mobile phone that requested the call start transmits a selection instruction as to whether or not to transmit the participation request notification to the mediation server, and the request notification transmission means receives the request. The participation request notification may be transmitted only when the selection instruction instructs transmission of the participation request notification.

  As a result, it is possible to select in advance whether or not to notify the participation request to the mediation server for the mobile phone that is not participating at the start of the PTT call. When it is known in advance that there is no possibility of recovery from the non-participating state, it is possible to avoid applying unnecessary processing load to the mediation server.

  Here, in the configuration 1, the change notification unit is changed when there is a change in the participation state and an image storage unit that stores a plurality of state images indicating the participation state for each mobile phone. The mobile phone that has been changed to read the state image indicating the participation state after the change from the image storage means, and transmit to each mobile phone that is participating in the PTT call, The mobile phone may display the state image on the display unit when the state image is received.

  Further, in the configuration 2, the change notification means includes an image storage means for storing a plurality of state images indicating participation states for each of the mobile phones and a change when the participation state is changed. The mobile phone may further include an image transmission unit that reads a state image indicating the changed participation state from the image storage unit and transmits the state image to the mobile phone that is participating in the PTT call.

  As a result, the user can easily recognize from the image displayed on the display unit that the participation state of the PTT call partner has changed.

(Embodiment)
The best mode for carrying out the present invention will be described below with reference to the drawings.
<Configuration>
FIG. 1 is a functional block diagram showing a configuration of a PTT call system 50 according to the present embodiment. The PTT call system 50 includes cellular phones 1 to 8, a network 10, base stations 11 to 13, edge servers (hereinafter referred to as “ES”) 21 to 23, and PTT call mediation servers (hereinafter referred to as “mediation servers”). 40.

Here, for convenience of explanation, the number of each component of the PTT call system 50 is limited, but FIG. 1 shows an example of the configuration of the PTT call system 50, and the number of each component is The number is not limited to the number shown in FIG. 1, and may be more or less.
(Network 10)
A network connected via the Internet or an intranet.
(Base stations 11-13)
It is provided for each area of a predetermined size, wirelessly connected to the mobile phones 1 to 8 and connected to the network 10.
(ES21-23)
An IP address is assigned to each of the base stations 11 to 13 and assigned to the mobile phones 1 to 8.
(Mediation server 40)
FIG. 2 is a functional block diagram showing the configuration of the mediation server 40. The mediation server 40 includes an interface unit 41, a mobile phone management unit 42, a user information storage unit 43, a PTT phone book synchronization management unit 44, a PTT phone book storage unit 45, a PTT mediation processing unit 46, a voice data storage unit 47, and a PTT call. The information search unit 48 and the PTT call information storage unit 49 are configured, and communication between the mediation server 40 and the mobile phones 1 to 8 is performed using SIP (Session Initiation Protocol).

(Interface part 41)
Communication with each component of the PTT call system 50 connected to the network 10 is performed.
(Mobile phone management unit 42)
It manages the participation status of mobile phones participating in PTT calls.

  Specifically, based on the recording instruction from the PTT mediation processing unit 46, the PTT call ID of the mobile phone requested to participate in the PTT call is stored in the user information storage unit 43, and thereafter, from the PTT mediation processing unit 46, Each time a change in the participation state of the mobile phone is notified, the PTT call ID of the mobile phone whose participation state has shifted to the non-participation state is deleted from the user storage unit 43, and the participation state changes from the non-participation state to the participating state. The PTT call ID of the migrated mobile phone is stored in the user information storage unit 43.

Here, the “PTT call ID” refers to an identifier uniquely added to each mobile phone in order to identify each mobile phone of the mobile phones 1 to 8.
(User information storage unit 43)
The PTT call ID of the mobile phone participating in the PTT call is stored.
(PTT phone book synchronization management unit 44)
The phone book of the PTT call group (hereinafter referred to as “group phone book”) stored in the PTT phone book storage unit 45 and the group phone book stored in the mobile phone belonging to the PTT call group have the same contents. Manage to be.

  Specifically, in any mobile phone belonging to the PTT call group, when the group phone book is updated, the updated group phone book is transmitted to the mediation server 40, and the PTT phone book synchronization management unit 44 transmits The received group phone book is received via the interface unit 41, stored in the PTT phone book storage unit 45, and the update is performed by notifying other mobile phones belonging to the PTT call group that the group phone book has been updated. The later group phone book is downloaded from the PTT phone book storage unit 45.

  Here, the “group phone book” means a group name for identifying a PTT call group, a contact name representing a nickname of a user of each mobile phone belonging to the PTT call group, a PTT call ID of each mobile phone, An image showing the participation state of the mobile phone in the PTT call (hereinafter referred to as “state image”), specifically, whether the participation state is (1) participating in the PTT call, or (2) the mobile phone is It is information including each state image indicating whether it is in a non-participating state in a non-connected state with a base station, or (3) in a non-participating state in accordance with a PTT call termination instruction from the mobile phone.

The state image of (1) is called “participating state image”, the state image of (2) is called “unconnected state image”, and the state image of (3) is called “call end state image”.
FIG. 6 shows a specific example of the group phone book. Reference numerals 601, 602, 603, and 604 in FIG. 6 indicate group telephone books, respectively.
FIG. 7 shows a specific example of a state image of the mobile phone. FIG. 7A shows a participating state image, FIG. 7B shows a disconnected state image, and FIG. 7C shows a call end state image.

(PTT phonebook storage unit 45)
Remember group phone book.
(PTT mediation processing unit 46)
As shown below, PTT call start processing, connection status monitoring processing, and voice data mediation processing are performed.
1. PTT Call Start Processing When the PTT mediation processing unit 46 receives a PTT call start request and designation of a PTT call group from any of the mobile phones 1 to 8 via the interface unit 41, the PTT phone book synchronization management unit 44 The PTT call ID of each mobile phone belonging to the specified PTT call group is identified through the mobile phone management unit 42 and the PTT call information search unit 48, and the PTT of each specified mobile phone is identified. A call ID is notified (hereinafter referred to as “participation candidate notification”), and a URI (Uniform Resource Identifier) indicating a communication mediation destination of the voice data of the PTT call and a PTT call start request are received via the interface unit 41. The INVITE information indicating the fact is transmitted to the specified mobile phone (the mobile phone excluding the mobile phone that requested the PTT call start). Request to participate in the PTT call, and notify the mobile phone management unit 42 and the PTT call information search unit 48 of the PTT call ID of the mobile phone in response to the participation request (hereinafter referred to as “participation notification”). A PTT call start process completion notification indicating that the PTT call start process has been completed and a status image of each mobile phone acquired from the PTT call information search unit 48 are transmitted to each mobile phone identified as connection status information. Start a PTT call.

Here, the state image transmitted as connection status information to each mobile phone is a state image excluding the state image of the destination mobile phone. The same applies to the connection status monitoring process 2 described later.
In addition, it is good also as transmitting including the state image of the mobile telephone of a transmission destination.
2. Connection Status Monitoring Processing The PTT mediation processing unit 46 specifies a mobile phone that is participating in the PTT call by inquiring the PTT call information search unit 48, and the base station Inquires about the wireless connection status with a fixed time interval, determines whether the mobile phone is wirelessly connected based on the response result from the base station, and manages the mobile phone if it is not connected to the base station Notification of the PTT call ID of the unconnected mobile phone (hereinafter referred to as “non-connection notification”) to the unit 42 and the PTT call information search unit 48, and the mobile phone of the notified PTT call ID When the state image corresponding to the unconnected state is acquired from the PTT call information search unit 48, the acquired state image is used as the connection state information to the mobile phone during the PTT call. The data is transmitted via the communication unit 41.

  When a PTT call termination instruction from a mobile phone that has intentionally ended the PTT call (the PTT call has been terminated by a user operation) is received via the interface unit 41, the mobile phone management unit 42 and the PTT call information search The unit 48 is notified of this and the PTT call ID of the terminated mobile phone (hereinafter referred to as “call end notification”), and corresponds to the PTT call end state of the mobile phone having the notified PTT call ID. When the status image is acquired from the PTT call information search unit 48, the acquired status image is transmitted as connection status information to the mobile phone during the PTT call via the interface unit 41.

  Further, when a PTT call re-participation request is received from a mobile phone that has intentionally terminated the PTT call, the mobile phone management unit 42 and the PTT call information search unit 48 are notified of the fact and the PTT call ID of the mobile phone (hereinafter referred to as “PTT call ID”). When the status image corresponding to the PTT call participation status is acquired from the PTT call information search unit 48 for the mobile phone with the notified PTT call ID, the acquired status image is connected. The status information is transmitted via the interface unit 41 to the mobile phone in the PTT call.

In addition, a URI of an ongoing PTT call is transmitted to a mobile phone that has not responded to the participation request for a predetermined period, and a request for participation in the PTT call is continuously made. When a halfway participation request is received from the telephone, the mobile phone management unit 42 and the PTT call information search unit 48 are notified of the fact and the PTT call ID of the mobile phone (hereinafter referred to as “halfway participation notification”). When a state image corresponding to the PTT call participation state for the mobile phone with the notified PTT call ID is acquired from the PTT call information search unit 48, the acquired state image is used as connection status information to interface with the mobile phone during the PTT call. It transmits via the part 41.
3. Audio data mediation processing During the PTT call, the PTT mediation processing unit 46 receives audio data transmitted from each mobile phone participating in the PTT call via the interface unit 41, and stores it in the audio data storage unit 47. The stored voice data is transmitted to the mobile phone participating in the PTT call other than the mobile phone that transmitted the voice data via the interface unit 41 (voice data storage unit 47).
Voice data transmitted from each mobile phone during a PTT call is stored.

(PTT call information search unit 48)
The update process of the participation state of each mobile phone in the PTT call and the search process of the state image when the participation state is updated are performed.
1. Participation State Update Processing The PTT call information search unit 48 corresponds to the participation state specification table stored in the PTT call information storage unit 49 based on each notification from the PTT mediation processing unit 46 in the connection status monitoring processing. Update the PTT call participation state of the mobile phone.

  Here, the “participation state specifying table” refers to a PTT call ID of a mobile phone (hereinafter referred to as “participation candidate mobile phone”) that has been notified of a participation candidate in the PTT call start processing, and a PTT call participating in the PTT call. This is a table indicating the correspondence between the PTT call ID of a mobile phone (hereinafter referred to as “participating mobile phone”), the PTT call ID of an unconnected mobile phone, and the PTT call ID of an end-of-call mobile phone.

Here, the “unconnected mobile phone” is a state in which, in the PTT call start process, the PTT call start process is not responding to the participation request or is not connected to the base station and is not participating in the PTT call. Refers to the mobile phone in
The “call-ending mobile phone” refers to a mobile phone that intentionally ends the PTT call and is not participating in the PTT call.

FIG. 8 shows a specific example of the participation state specifying table.
When the PTT call information search unit 48 receives the participation candidate notification from the PTT mediation processing unit 46, the PTT call information search unit 48 records the PTT call ID of the participation candidate mobile phone in the participation candidate mobile phone column of the participation status specifying table, and further performs the PTT mediation processing. When the participation notification is received from the unit 46, the PTT call ID of the mobile phone notified of the participation is recorded in the column of the participating mobile phone in the participation state specifying table, and the PTT call ID of the mobile phone not notified of the participation is recorded. It records in the column of the unconnected mobile phone in the participation state specifying table (see FIG. 8A).

  Next, when a disconnection notification is received from the PTT mediation processing unit 46, the PTT call ID of the mobile phone for which the disconnection notification has been received is deleted from the column of the participating mobile phone in the participation state specifying table, and the deleted PTT call ID is deleted. Is recorded in the column of the unconnected mobile phone (see FIG. 8D), and when the mid-participation notification is received, the PTT call ID of the mobile phone for which the mid-participation notification has been received is stored in the non-connected mobile phone column of the participation state specifying table And the deleted PTT call ID is recorded in the column of the participating mobile phone (see FIG. 8B).

When a call end notification is received from the PTT intermediary processing unit 46, the PTT call ID of the mobile phone that intentionally ends the PTT call is deleted from the participating mobile phone column of the participation state specifying table, and the call end mobile phone When the re-participation notification is received, the PTT call ID of the mobile phone that has been notified of the re-participation is recorded in the participation state specifying table. Delete the PTT call ID from the field and record the deleted PTT call ID in the participating mobile phone field (see FIG. 8B).
2. State image search processing The PTT call information search unit 48 displays the PTT call participation state of each mobile phone specified by the participation state specification table updated based on each notification from the PTT mediation processing unit 46 in the connection status monitoring process. The telephone directory synchronization management unit 44 is notified, the corresponding state image is searched for each notified mobile phone, each searched state image is received from the PTT telephone directory synchronization management unit 44, and is output to the PTT mediation processing unit 46. .

(PTT call information storage unit 49)
A participation state specifying table is stored.
(Mobile phones 1-8)
Since the configurations of the cellular phones 1 to 8 are the same, the cellular phone 1 will be described below as an example.
FIG. 4 is a functional block diagram showing the configuration of the mobile phone 1. The mobile phone 1 includes a speaker unit 101, a microphone unit 102, an operation unit 103, a display unit 104, an antenna 105, a communication unit 106, a control unit 107, and a storage unit 108.

(Speaker unit 101)
An audio signal input from the control unit 107 from the mobile phone of the PTT call partner is output.
(Microphone unit 102)
A call voice from the user is received and output to the control unit 107 as a voice signal.

(Operation unit 103)
Various instructions from the user are received and output to the control unit 107.
(Display unit 104)
The state image of the mobile phone transmitted from the mediation server 40 is displayed.
(Antenna 105)
Communication radio waves including various information such as call voice data, connection status information, a PTT call start request, and a PTT call participation request are transmitted and received.

(Communication unit 106)
The communication radio wave input from the antenna 105 is demodulated and output to the control unit 107. The communication data including various information input from the control unit 107 is modulated and output to the antenna 105 as a communication radio wave.
(Control unit 107)
The cellular phone 1 is configured by a microprocessor, a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and controls the entire mobile phone 1 according to a control program stored in the ROM.

  The control unit 107 receives various instructions (a PTT sum start request, a PTT call end instruction, a PTT call participation response, a PTT call rejoin request, a PTT call halfway join request, etc.) input from the operation unit 103 from the user as a mediation server 40, notifies the participation / non-participation in the PTT call, and causes the display unit 104 to display an updated status image included in the connection status information each time the connection status information is received from the mediation server 40. .

Here, in the PTT call start request, the control unit 107 transmits the PTT call group name selected by the user from the group phone book stored in the storage unit 108 and the PTT call ID of the mobile phone 1 to the mediation server 40. Is done. FIG. 5 shows a specific example of a PTT call group selection screen.
Further, the PTT call end instruction is received by a user pressing a PTT call end instruction button 103B of the operation unit 103, which will be described later, so that the control unit 107 receives the PTT call end instruction, and the PTT call end instruction and the PTT of the cellular phone 1 are received. This is performed by transmitting the call ID to the mediation server 40.

The PTT call participation response, the PTT call rejoin request, and the PTT call join request are performed by transmitting the URI and the PTT call ID of the mobile phone 1 to the mediation server 40 based on the input of an instruction from the user. Is called.
(Storage unit 108)
It stores state images and URIs transmitted from the group telephone directory and the mediation server 40.

FIG. 3 is a diagram showing an appearance of the mobile phone 1. Reference numeral 101 denotes a speaker unit, 102 denotes a microphone unit, 103 denotes an operation unit, 104 denotes a display unit, 103A denotes a PTT call button, and 103B denotes a PTT call end instruction button.
By pressing the PTT call button 103A, an IP address assignment request is issued to the ES 21 (see FIG. 1) corresponding to the base station 11 in which the mobile phone 1 is located.
<Operation>
(PTT call control processing)
Next, the operation of the PTT call control process performed by the mediation server 40 will be described. 9 and 10 are flowcharts showing the above operation.

  When the PTT intermediary processing unit 46 receives a PTT call start request specifying a PTT call group for starting a call from any of the mobile phones 1 to 8 via the interface unit 41 (step S901), the PTT phone book synchronization management A mobile phone excluding a mobile phone that makes a PTT call start request among the specified mobile phones by referring to the group phone book via the unit 44, specifying the PTT call ID of each mobile phone belonging to the specified PTT call group In response to this, the URI and INVITE information assigned to the PTT call are transmitted (step S902), and it is monitored whether or not there is a participation response from each mobile phone that transmitted the INVITE information (step S903).

  When there is a participation response (step S903: Y), the PTT mediation processing unit 46 notifies the participation to the PTT call information search unit 48, and acquires the start process completion notification and the PTT call information search unit 48 immediately before the start of the call. The state image of each mobile phone is transmitted as connection status information to each mobile phone that has participated in the response (step S904), the PTT call is started (step S905), and each mobile phone participating in the PTT call (Step S906), and inquires each base station connected to each participating mobile phone about the wireless connection status with the mobile phone at regular intervals (step S907). When the response result from the base station is “not connected” (step S908: Y), the PTT mediation processing unit 46 communicates with the PTT call information search unit 48 without connection. The state image corresponding to the PTT call participation state of each mobile phone in the participation state specifying table updated based on the disconnection notification is acquired from the PTT call information search unit 48, and the acquired state image is updated after connection. The situation information is transmitted to each mobile phone participating in the PTT call via the interface unit 41 (step S909), and it is monitored whether a call end instruction is received from each mobile phone participating in the PTT call (step S910).

  When received (step S910: Y), a call end notification is sent to the PTT call information search unit 48, and the state corresponding to the PTT call participation state of each mobile phone in the participation state specifying table updated based on the call end notification An image is acquired from the PTT call information search unit 48, and the acquired status image is transmitted as updated connection status information to each mobile phone participating in the PTT call via the interface unit 41 (step S911). It is monitored whether a PTT call rejoin request is received from the terminated mobile phone (step S912).

If received (step S912: Y), the PTT intermediary processing unit 46 inquires of the PTT call information search unit 48 about the current PTT call participation status, and determines whether there is a mobile phone participating in the PTT call. It is determined whether or not the process has ended (step S913).
If there is a mobile phone that is participating in a PTT call and it is determined that the PTT call has not ended (step S913: Y), a re-participation notification is sent to the PTT call information search unit 48, and the re-participation notification is made. A status image corresponding to the PTT call participation status of each mobile phone in the updated participation status specification table is acquired from the PTT call information search unit 48, and the acquired status image is used as connection status information after the update to indicate that the PTT call is participating. The data is transmitted to each mobile phone through the interface unit 41 (step S914), and the process proceeds to step S907.

In step S912, when the PTT call re-participation request has not been received (step S912: N), the PTT intermediary processing unit 46 inquires of the PTT call information search unit 48 about the current PTT call participation state, and is participating in the PTT call. It is determined whether or not the PTT call is ended depending on whether or not there is a mobile phone (step S915).
In step S903, when there is no participation response from any of the mobile phones (step S903: N), the PTT mediation processing unit 46 sends the URI and INVITE information assigned to the PTT call to the mobile phone that has not received the participation response. It retransmits (step S916), and monitors whether there is a PTT call midway participation request from the mobile phone (step S917).

When there is a request for participation in the middle of a PTT call (step S917: Y), the PTT mediation processing unit 46 inquires of the PTT call information search unit 48 about the current PTT call participation state, and whether there is a mobile phone participating in the PTT call. Therefore, it is determined whether or not the PTT call has ended (step S918).
If there is a mobile phone that is participating in a PTT call and it is determined that the PTT call has not ended (step S918: Y), a participation permission notification is transmitted to the mobile phone that has requested participation during the PTT call, The PTT call information search unit 48 notifies the halfway participation, and acquires from the PTT call information search unit 48 a state image corresponding to the PTT call participation state of each mobile phone in the participation state specifying table updated based on the halfway participation notification. The acquired status image is transmitted as updated connection status information to each mobile phone participating in the PTT call via the interface unit 41 (step S919).

In step S917, when there is no midway participation request (step S917: N), the PTT mediation processing unit 46 determines whether or not a certain time has elapsed since the first retransmission (step S920). If not (step S920: N), the process proceeds to step S916.
In step S908, if the response result from the base station is “connected” (step S908: N), the PTT mediation processing unit 46 proceeds to the process in step S910, and in step S910, a call termination instruction is issued. If not received (step S910: N), the process proceeds to step S915. If no PTT call rejoin request is received in step S912 (step S912: N), the process proceeds to step S915.
(Example of mid-participation processing)
Next, regarding the operation example of the midway participation mediation process (corresponding to the processes of steps S901 to S905 and steps S916 to S920 in FIG. 9) performed by the PTT call system 50, each mobile phone belonging to the PTT call group designated as the mediation server 40 The description will focus on the relationship with the telephone (here, for convenience of explanation, any one of the cellular phones 1 to 8).

11 and 12 are flowcharts showing the above operation example.
When one of the mobile phones belonging to the PTT call group (hereinafter referred to as “start request mobile phone”) designates the PTT call group name and makes a PTT call start request (step S11), the mediation server 40 9, each mobile phone except the start requesting mobile phone among the mobile phones belonging to the PTT call group for which the INVITE information is designated (hereinafter referred to as “receiving-side mobile phones 1, 2, 4”, respectively) (Referred to as “unconnected mobile phone 3 at start”) (step S13), and there is a participation response from the incoming side mobile phones 1, 2, and 4 (steps S14 to 16). If there is no participation response, the mediation server 40 determines the participation status specifying table of the participation status of each mobile phone belonging to the designated PTT call group. (Step S17), and in accordance with the processing of step S904 in FIG. 9, a status image indicating the PTT call participation status of each mobile phone is transmitted as connection status information to each mobile phone except the unconnected mobile phone 3 at the start. (Step S18).

The start requesting mobile phone and the receiving-side mobile phones 1, 2, and 4 that have received the connection status information display the received connection status information on the display unit 104 (steps S19 to S22), and start a PTT call (step S23). -Step S26).
The mediation server 40 repeatedly repeats the URI and INVITE information assigned to the designated PTT call for a certain period of time to the unconnected mobile phone 3 at the start without participation response in accordance with the processing of steps S916, 917, and 920 in FIG. Transmit (step S27).

Upon receiving the URI and INVITE information (step S28), the unconnected mobile phone 3 at the start transmits a PTT call midway participation request to the mediation server 40 (step S29).
When the mediation server 40 receives the PTT participation request, it confirms the PTT call state according to the process of step S918 in FIG. 9 (step S30), and if the PTT call has not ended, the intermediary server 40 The participation permission notification is sent (step S31), the PTT call participation state of the participation state specifying table is updated (step S32), and the updated connection status information is designated in accordance with the process of step S919 of FIG. Is transmitted to each mobile phone belonging to (step S33).

Each mobile phone displays the received connection status information on the display unit 104 (steps S34 to S38).
(Operation example of mid-call termination and call resumption processing)
Next, as for the operation example of the mid-call termination and call resumption processing (corresponding to the processing in steps S910 to S914 in FIG. 10) performed by the PTT call system 50, the mediation server 40 is similar to the operation example of the midway participation processing. And the mobile phone (here, for convenience of explanation, any one of the mobile phones 1 to 8 is assumed).

13 and 14 are flowcharts showing the above operation example.
In FIG. 13, the PTT call group is specified, the mobile phone that has started the PTT call is the start requesting mobile phone, and the mobile phones that are participating in the PTT call are called the receiving side mobile phones 1 to 4.
Of the mobile phones in the PTT call state (steps S41 to S45), the receiving mobile phone 4 transmits a PTT call end instruction to the mediation server 40 (step S46).

The mediation server 40 receives the PTT call end instruction (step S47), updates the PTT call participation state of the participation state specifying table (step S49), and updates the updated connection status information according to the process of step S911 of FIG. Then, it is transmitted to each mobile phone except the incoming side mobile phone 4 (step S50).
The start requesting mobile phone and the receiving side mobile phones 1 to 3 display the updated connection status information on the display unit 104 (steps S51 to S54).

Thereafter, the called mobile phone 4 transmits a PTT call rejoin request to the mediation server 40 (step S55).
When the mediation server 40 receives the PTT participation request, the intermediary server 40 confirms the PTT call state according to the process of step S913 in FIG. 9 (step S56), and if the PTT call has not ended, An approval notification is sent (step S57), the PTT call participation state in the participation state specifying table is updated (step S58), and the updated connection status information belongs to the designated PTT call group according to the process of step S914 in FIG. It transmits to each mobile phone (step S59).

The start requesting mobile phone and the receiving side mobile phones 1 to 4 display the received updated connection status information on the display unit 104 (steps S60 to S64), and the receiving side mobile phone 4 resumes the PTT call ( Step S65).
(Example of wireless connection management processing)
Next, in the same way as the operation example of the midway participation process in the operation example of the wireless connection management process (corresponding to the process in steps S907 to S909 in FIG. 9) performed by the PTT call system 50, the mediation server 40 and the mobile phone ( Here, for convenience of explanation, the description will focus on the relationship with any one of the mobile phones 1 to 8. FIG. 16 is a flowchart showing the above operation example.

In FIG. 16, the PTT call group is designated, the mobile phone that has started the PTT call is the start requesting mobile phone, and the mobile phones that are participating in the PTT call are called the receiving side mobile phones 1 to 4.
When each mobile phone starts a call (steps S71 to S75), the mediation server 40 confirms the connection status of each mobile phone to the base station at regular time intervals according to step S907 in FIG. 9 (step S76). When the receiving side mobile phone 1 is disconnected from the base station (step S77), this is detected based on the confirmation result, and the PTT participation state in the participation state specifying table is updated (step S78). According to the processing of 909, the updated connection status information is transmitted to each mobile phone except for the incoming side mobile phone 1 (step S79).

The start requesting mobile phone and the receiving side mobile phones 2 to 4 display the received updated connection status information on the display unit 104 (steps S80 to S83).
FIG. 15 shows a specific example of the state image displayed on the display unit 104 of each mobile phone participating in the PTT call.
FIG. 15A is a specific example of the state image displayed on the display unit 104 of the start request mobile phone in step S19 of FIG. 1301 is a status image of the receiving side mobile phone 1, 1302 is a status image of the receiving side mobile phone 2, 1303 is a status image of the unconnected mobile phone 3 at the start, and 1304 is a status image of the receiving side mobile phone 4. A state image is shown.

FIG. 15B is a specific example of the state image displayed on the display unit 104 of the start request mobile phone in step S34 of FIG. Reference numeral 1305 denotes a state image of the unconnected mobile phone 3 at the start of participation in the PTT call halfway.
FIG. 15C is a specific example of the state image displayed on the display unit 104 of the start request mobile phone in step S51 of FIG. Reference numeral 1306 denotes a state image of the incoming-side mobile phone 4 which has instructed to end the PTT communication during the PTT call.

FIG. 15D is a specific example of the state image displayed on the display unit 104 of the start request mobile phone in step S80 of FIG. Reference numeral 1307 denotes a state image of the incoming-side mobile phone 1 that is in a disconnected state during a PTT call.
<Supplement>
As mentioned above, although embodiment of this invention was described, of course, this invention is not limited to these embodiment.
(1) For example, in the present embodiment, before starting the PTT call, the URI and INVITE information are repeatedly retransmitted for a certain period of time to the mobile phone that has not participated in response to the INVITE information transmitted from the mediation server 40. However, instead of retransmitting, the URI and INVITE information may be sent by e-mail to the mobile phone.

In addition, the mobile phone side selects whether or not to perform the re-transmission or mail transmission, and the mediation server 40 receives an instruction from the mobile phone to perform the re-transmission or mail transmission when a PTT call start request is made. The re-transmission or mail transmission may be performed only when it is transmitted.
(2) Also, in this embodiment, when the PTT call participation state of each mobile phone is changed, the mediation server 40 transmits a state image indicating that fact to each mobile phone participating in the PTT call, and displays it. However, instead of transmitting the status image, information (for example, character information) indicating the PTT call participation status of each mobile phone may be transmitted to each mobile phone participating in the PTT call and displayed. .

On the mobile phone side, based on the above information, the mobile phone whose call state has been changed is identified, and the state image whose call state has been changed is displayed by blinking or highlighting the state image. It may be displayed.
Further, based on the above information, the corresponding state image may be read from the group phone book stored in the storage unit 108 on the mobile phone side and displayed on the display unit 104.
(3) In the present embodiment, when the PTT call participation state of each mobile phone is changed, not only the changed mobile phone state image but also the other mobile phone PTT call participation states are shown. As for the state image, the mediation server 40 transmits to each mobile phone that is participating in the PTT call. However, only the changed state image may be transmitted.
(4) In the present embodiment, whether or not the PTT call has ended is determined based on whether or not there is a mobile phone that is participating in the PTT call. Good. For example, when there is a PTT call end instruction from a mobile phone that has requested PTT call start, it may be determined that the PTT call has ended.

INDUSTRIAL APPLICABILITY The present invention can be used in a push-to-talk (PTT) call system as a technique for controlling display of a call partner during a PTT call.

2 is a functional block diagram showing a configuration of a PTT call system 50. FIG. 3 is a functional block diagram showing a configuration of an intermediary server 40. FIG. 1 is a diagram showing an external appearance of a mobile phone 1. FIG. 2 is a functional block diagram showing a configuration of a mobile phone 1. FIG. The example of the selection screen of a PTT call group is shown. A specific example of a group telephone book is shown. A specific example of a state image of a mobile phone is shown. A specific example of the participation state specifying table is shown. It is a part of flowchart which shows the operation | movement of the PTT call control process which the mediation server 40 performs. It is a part of flowchart which shows the operation | movement of the PTT call control process which the mediation server 40 performs. 7 is a part of a flowchart showing an operation example of midway participation mediation processing performed by the PTT call system 50. 7 is a part of a flowchart showing an operation example of midway participation mediation processing performed by the PTT call system 50. 7 is a part of a flowchart showing an operation example of mid-call termination and call resumption processing performed by the PTT call system 50. 7 is a part of a flowchart showing an operation example of mid-call termination and call resumption processing performed by the PTT call system 50. A specific example of the state image displayed on the display unit 104 of each mobile phone participating in the PTT call is shown. 6 is a flowchart showing an operation example of wireless connection management processing performed by the PTT call system 50.

Explanation of symbols

1-8 Cellular Phone 11-13 Base Station 21-23 Edge Server 40 Mediation Server 41 Interface Unit 42 Cellular Phone Management Unit 43 User Information Storage Unit 44 PTT Phonebook Synchronization Management Unit 45 PTT Phonebook Storage Unit 46 PTT Mediation Processing Unit 47 Voice data storage unit 48 PTT call information search unit 49 PTT call information storage unit 50 PTT call system 101 Speaker unit 102 Microphone unit 103 Operation unit 104 Display unit 105 Antenna 106 Communication unit 107 Control unit 108 Storage unit

Claims (19)

It has a function of performing communication between a plurality of mobile phones using a network, and includes a plurality of mobile phones having a display unit, and an intermediary server that mediates the communication in which each mobile phone can participate. Communication system,
The intermediary server monitors the connection state of each mobile phone participating in the communication with a base station and the call state of each mobile phone after the start of the communication, thereby A monitoring means for monitoring a change in the communication participation state;
Change notification means for notifying each of the mobile phones participating in the communication of the monitoring result when there is a change in the participation state in any of the mobile phones,
When each of the mobile phones participating in the communication is notified, information on at least one of a connection state with the base station and the call state is displayed on the display unit based on the notification. Ru to display,
A communication system characterized by the above. It has a function of performing communication between a plurality of mobile phones using a network, and includes a plurality of mobile phones having a display unit, and an intermediary server that mediates the communication in which each mobile phone can participate. Communication system,
The intermediary server monitors the connection state of each mobile phone participating in the communication with a base station and the call state of each mobile phone after the start of the communication, thereby A monitoring means for monitoring a change in the communication participation state;
Change notification means for notifying each of the mobile phones participating in the communication of the monitoring result when the participation state is changed in any of the mobile phones,
Each of the mobile phones participating in the communication participates in at least one of a connection state with the base station and the call state on the display unit based on the notification when the notification is given. Display status change information,
The change notification means includes
For each of the mobile phones, an image storage unit that stores a plurality of state images that display participation state change information corresponding to the monitoring results ,
When there is a change in the participation state, the state image corresponding to the monitoring result is read from the image storage unit for the mobile phone that has been changed, and is transmitted to each mobile phone that is participating in the communication Transmission means, and
Each mobile phone, when receiving the state image, displays the state image on the display unit as the participation state change information . Each of the mobile phones has interruption notification transmission means for transmitting a participation interruption notification for notifying the communication server of participation interruption in response to a user instruction,
The monitoring means includes interruption detection means for monitoring reception of the participation interruption notification and attempting to detect the participation interruption notification;
3. The communication according to claim 1, wherein, when the detection is made, the change notification unit notifies the mobile phones participating in the communication that the participation has been interrupted. 4. system. Each of the mobile phones has re-participation request transmission means for transmitting a re-participation request for requesting re-participation in the communication in response to a user instruction.
The interruption detection means detects the rejoin by receiving the rejoin request,
4. The communication system according to claim 3, wherein, when the detection is made, the change notification unit notifies each of the mobile phones participating in the communication that the re-participation has occurred. The mediation server starts the communication in response to the communication start request from any of the mobile phones,
The monitoring means includes
Detecting means for detecting a participation state of each mobile phone at the start of the communication;
A request notification transmitting means for repeatedly transmitting a participation request notification for requesting the mobile phone to participate in the communication for a predetermined period when the mobile phone in a non-participating state is detected;
Each mobile phone has a response notification transmission means for transmitting a response notification to the mediation server when the participation request notification is received;
The monitoring unit includes a midway participation detection unit that monitors reception of the response notification and tries to detect the response notification.
The change notification means, when the detection is made, notifies the mobile phone that is participating in the communication that the mobile phone in a non-participating state has joined the communication halfway. The communication system according to any one of claims 1 to 4. The mediation server starts the communication in response to the communication start request from any of the mobile phones,
The monitoring means includes
Detecting means for detecting a participation state of each mobile phone at the start of the communication;
A request notification transmitting means for transmitting a participation request notification for requesting participation in the communication to the address of the mobile phone when the mobile phone in a non-participating state is detected;
Each mobile phone has a response notification transmission means for transmitting a response notification to the mediation server when the participation request notification is received;
The monitoring unit includes a midway participation detection unit that monitors reception of the response notification and tries to detect the response notification.
The change notification means, when the detection is made, notifies the mobile phone that is participating in the communication that the mobile phone in a non-participating state has joined the communication halfway. The communication system according to any one of claims 1 to 4. The mobile phone that requested the communication start transmits a selection instruction as to whether or not to transmit the participation request notification to the mediation server,
The communication system according to claim 5 or 6, wherein the request notification transmission unit transmits the participation request notification only when the received selection instruction instructs transmission of the participation request notification. . A mediation server having a function of performing communication between a plurality of mobile phones using a network, and mediating the communication in which a plurality of mobile phones having a display unit can participate,
After the start of the communication, the connection state of each mobile phone participating in the communication with the base station and the call state of each mobile phone are monitored, whereby the participation state of each mobile phone in the communication Monitoring means for monitoring changes in
Change notification means for notifying the monitoring result to the mobile phone participating in the communication when the participation state is changed in any of the mobile phones,
Mediation server, wherein the Ru with the. A mediation server having a function of performing communication between a plurality of mobile phones using a network, and mediating the communication in which a plurality of mobile phones having a display unit can participate,
After the start of the communication, the connection state of each mobile phone participating in the communication with the base station and the call state of each mobile phone are monitored, whereby the participation state of each mobile phone in the communication Monitoring means for monitoring changes in
Change notification means for notifying the monitoring result to the mobile phone participating in the communication when the participation state is changed in any of the mobile phones,
With
The change notification means includes
For each of the mobile phones, an image storage unit corresponding to the monitoring result and storing a state image relating to a connection state with the base station and a state image relating to the call state ;
When there is a change in the participation state, an image transmission for reading the state image corresponding to the monitoring result from the image storage unit and transmitting the state image corresponding to the monitoring result to the mobile phone participating in the communication An intermediary server comprising: means. The monitoring means monitors the reception of a participation interruption notification for notifying the participation interruption to the communication to be transmitted from any of the mobile phones participating in the communication, and attempts to detect the participation interruption. Having detection means;
The mediation according to claim 8 or 9, wherein, when the detection is detected, the change notification unit notifies the mobile phones participating in the communication that the participation has been interrupted. server. The interruption detection means monitors reception of a re-participation notification requesting re-participation in the communication, transmitted from the mobile phone that has made the participation interruption notification, and tries to detect the re-participation notification,
The intermediary server according to claim 10, wherein, when the detection is made, the change notification unit notifies the mobile phones participating in the communication that the re-participation has occurred. The mediation server starts the communication in response to the communication start request from any of the mobile phones,
The monitoring means includes
Detecting means for detecting a participation state of each mobile phone at the start of the communication;
A request notification transmitting means for repeatedly transmitting a participation request notification for requesting participation in the communication to the mobile phone for a predetermined period when the mobile phone in a non-participating state is detected;
When the participation request notification is received by the mobile phone in a non-participating state, monitoring is performed for reception of a response notification transmitted from the mobile phone, and halfway participation detection means for attempting to detect the response notification is provided. And
The change notification means, when the detection is made, notifies the mobile phone that is participating in the communication that the mobile phone in a non-participating state has joined the communication halfway. The mediation server according to any one of claims 8 to 11. The mediation server starts the communication in response to the communication start request from any of the mobile phones,
The monitoring means includes
Detecting means for detecting a participation state of each mobile phone at the start of the communication;
A request notification transmission means for transmitting a participation request notification for requesting participation in the communication to the address of the mobile phone when the mobile phone in a non-participating state is detected;
When the participation request notification is received by the mobile phone in a non-participating state, monitoring is performed for reception of a response notification transmitted from the mobile phone, and halfway participation detection means for attempting to detect the response notification is provided. And
The change notification means, when the detection is made, notifies the mobile phone that is participating in the communication that the mobile phone in a non-participating state has joined the communication halfway. The mediation server according to any one of claims 8 to 11. A mobile phone having a function of performing communication between a plurality of mobile phones using a network via a mediation server, and having a display unit,
  The intermediary server monitors the connection state of each mobile phone participating in the communication with a base station and the call state of each mobile phone after the start of the communication, thereby A monitoring means for monitoring a change in the communication participation state;
  Change notification means for notifying each of the mobile phones participating in the communication of the monitoring result when there is a change in the participation state in any of the mobile phones,
The mobile phone is
Receiving means for receiving the notification;
Display control means for displaying information on at least one of a connection state with the base station and the call state on the display unit based on the received notification;
A mobile phone comprising: A mobile phone having a function of performing communication between a plurality of mobile phones using a network via a mediation server, and having a display unit,
The intermediary server monitors the connection state of each mobile phone participating in the communication with a base station and the call state of each mobile phone after the start of the communication, thereby A monitoring means for monitoring a change in the communication participation state;
Change notification means for notifying each of the mobile phones participating in the communication of the monitoring result when the participation state is changed in any of the mobile phones,
The change notification means includes
For each of the mobile phones, an image storage unit corresponding to the monitoring result and storing a state image relating to a connection state with the base station and a state image relating to the call state ;
When there is a change in the participation state, the state image corresponding to the monitoring result is read from the image storage unit for the mobile phone that has been changed, and is transmitted to each mobile phone that is participating in the communication Transmission means,
When the state image is received, the received state image is displayed on the display unit as information indicating that the change has occurred. A mobile phone having a function of performing communication between a plurality of mobile phones using a network via a mediation server, and including a display unit,
The intermediary server monitors the connection state of each mobile phone participating in the communication with a base station and the call state of each mobile phone after the start of the communication, thereby A monitoring means for monitoring a change in the communication participation state;
Change notification means for notifying each of the mobile phones participating in the communication of the monitoring result when the participation state is changed in any of the mobile phones,
The mobile phone corresponds to each of the monitoring results, an image storage means for storing a state image relating to a connection state with the base station, and a state image relating to the call state ;
When the notification is received, for the mobile phone that has changed, a display control unit that reads out a state image corresponding to the monitoring result from the image storage unit, and causes the display unit to display the state image;
A mobile phone comprising: A PTT call system comprising a plurality of mobile phones having a push-to-talk (PTT) call function and having a display unit, and an intermediary server that mediates the PTT call in which each mobile phone can participate,
The intermediary server monitors the connection state of each mobile phone that is participating in the PTT call with the base station and the call state of each mobile phone after the PTT call is started. Monitoring means for monitoring a change in the participation state of the PTT call
Change notification means for notifying each of the mobile phones participating in the PTT call when the participation state is changed in any of the respective mobile phones, and notifying the monitoring result .
Each of the mobile phones participating in the PTT call displays information on at least one of a connection state with the base station and the call state based on the notification when the notification is given. The
A PTT call system characterized by that. A PTT call system comprising a plurality of mobile phones having a PushTalk (PTT) call function and having a display unit, and an intermediary server that mediates the PTT call in which each mobile phone can participate,
The intermediary server monitors the connection state of each mobile phone that is participating in the PTT call with the base station and the call state of each mobile phone after the PTT call is started. Monitoring means for monitoring a change in the participation state of the PTT call
Change notification means for notifying each of the mobile phones participating in the PTT call when the participation state is changed in any of the respective mobile phones, and notifying the monitoring result .
When each of the mobile phones participating in the PTT call is notified, the participation state change information related to at least one of a connection state with the base station and the call state based on the notification Is displayed,
The change notification means includes
For each of the mobile phones, an image storage unit that stores a plurality of state images that display participation state change information corresponding to the monitoring results ,
When there is a change in the participation state, the state image corresponding to the monitoring result is read from the image storage unit and transmitted to each of the mobile phones participating in the PTT call when the mobile phone has changed. Image transmission means, and
When each of the mobile phones receives the status image, the mobile phone displays the status image on the display unit as the participation status change information . A mobile phone having a display unit having a push talk (PTT) call function, connected to an intermediary server that mediates a PTT call between a plurality of mobile phones,
  The intermediary server monitors the connection state of each mobile phone that is participating in the PTT call with the base station and the call state of each mobile phone after the PTT call is started. Monitoring means for monitoring a change in the participation state of the communication,
  Change notification means for notifying each of the mobile phones participating in the communication of the monitoring result when there is a change in the participation state in any of the mobile phones,
The mobile phone is
Receiving means for receiving the notification;
Display control means for displaying information on at least one of a connection state with the base station and the call state on the display unit based on the received notification;
A mobile phone comprising:

Images