JP2008219893A - Ringing control device and a ringing control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ringing control device and a ringing control method for utilizing network resource effectively, by reducing duplicating transfer of a control message. <P>SOLUTION: The ringing control device, which is connected with two or more terminals through a network, includes a control message management table for showing correlation between a ringing control message and a communication type, by which unicast/multicast is shown; and a control unit for deciding the communication type of the ringing request control message and a transmission destination terminal, which correspond to the ringing request control message in the control message management table, when the ringing request control message is received from the terminal. Then, a ringing response control message is transmitted to the transmission destination terminal through the decided communication type. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a call control device and a call control method that communicate with a plurality of wireless terminals, and more particularly, to a call control device and a call control method that are effective in a PoC (Push-to-talk over Cellular) system.

  In the OMA (Open Mobile Alliance) organization, the application of PoC used for 3GPP and 3GPP2 was specified. OMA is in charge of defining PoC (Push-to-talk over Cellular) technical standards not related to access technology, and 3GPP and 3GPP2 are in charge of developing PoC technical standards related to specific wireless networks.

PoC is one of the important applications of cellular communication networks, providing services similar to transceivers by providing a communication scheme that allows real-time communication between a user and one or more other users.
In application of PoC, for example, one group is formed by a plurality of PoC client terminals. In each group, a plurality of PoC client terminals cannot be the sender at the same time. While one PoC client terminal is transmitting a voice data flow, the other PoC client terminals can only be receivers and receive data. Can not.

  Transmission of the voice data flow from the PoC client terminal is controlled by the PoC server distributing tokens. Only the PoC client terminal that has obtained the token can transmit the voice data flow. It is necessary to transfer a control message between the PoC client terminal and the PoC server in order to exchange messages regarding tokens. When the voice data flow is transmitted from the PoC client terminal, the PoC server transfers the received voice data flow to each PoC client terminal.

  When transmitting the voice data packet by unicast, the PoC server needs to transmit a copy of the voice data packet to all the PoC client terminals in the group. This causes a problem that the load on the PoC server increases when the number of users in the group increases at the same time as waste of network resources occurs.

  As a conventional technique related to these problems, for example, US Pat. No. 6,141,347A (Patent Document 1) discloses a method for improving the transfer efficiency between a PoC server and a network. In Patent Document 1, network resources are saved mainly by transferring voice data packets using multicast. However, multicast is not supported in conventional normal cellular communication networks (eg, PoC).

  The 3GPP2 organization has proposed BCMCS (Broadcast / Multicast Service) to support multicast in cellular communication networks. By supporting multicast (3GPP2X.S0022-0 “Broadcast and Multicast Service in cdma2000 Wireless IP network”) in a cellular communication network, similar data can be simultaneously transmitted to a plurality of users. According to the above technique, data can be simultaneously transmitted to a plurality of wireless terminals using the control channel of the air interface. If this technology is adopted, multicast can be supported in the cellular communication network.

  When only downlink multicast data is transferred between the base station and the wireless terminal, the unicast channel resource consumption can be reduced by releasing the unicast channel resource between the wireless terminal and the base station. This technology can be applied to a PoC type group service in a 3G system. In the 3GPP2 standard, the control function of the multicast channel in the cellular network is achieved by the BCMCS controller.

US Pat. No. 6,141,347A

  The technique of Patent Document 1 employs a distributed control method to transfer only an audio data flow between different terminals. In such a distributed control method, effective management cannot be performed for a group, and thus there may be a conflict between different terminals in group communication. On the other hand, the OMA standard defines that a group is controlled by a PoC server. Thus, it is necessary to complete not only the voice data flow but also the control message to complete the group control function between the PoC client terminal and the PoC server.

  In the OMA standard, TBCP (Talk Burst Control Protocol) is defined as a control protocol for group control messages. In the OMA PoC standard, it is necessary to transfer a control message between the client terminal and the server, that is, a TBCP message in addition to the voice. However, the conventional technology only considers transferring the voice by multicast, and does not consider transferring the control message by multicast.

  When a control message such as a TBCP message is transmitted between the PoC client terminal and the PoC server in a unicast manner, the PoC client terminal maintains and controls the unicast channel even if the voice data flow is received through the BCMCS. The message needs to be transferred. Therefore, the unicast channel resource of the air interface is still occupied, and there is a problem that the channel resource is wasted.

  An object of the present invention is to provide a call control device and a call control method that can effectively use network resources by reducing duplicate transfer of control messages.

  In order to achieve the above object, the present invention provides a call control method executed by a call control device connected to a plurality of terminals via a network, the plurality of terminals via a network interface of the call control device. A reception step of receiving a call request control message transmitted from one of the above, and a control for a session between the plurality of terminals and the call control device stored in a storage device of the call control device Corresponding to the received call request control message by searching the control message management table indicating the correspondence between the call control message for performing communication and the communication type indicating whether the transfer method of the call control message is unicast or multicast. Confirm the communication type and destination terminal of the call response control message And step, based on the communication type, via the network interface, characterized in that it comprises a transmission step of transmitting the paging response control message to the determined terminal.

  More specifically, in the present invention, the control message management table stores unicast addresses of the plurality of terminals and multicast addresses of a multicast group to which each terminal belongs, and the communication is performed in the determining step. By searching the control message management table based on the type, the address corresponding to the communication type is determined, and in the transmission step, using the determined address, the network interface via the network interface The call response control message is transmitted to at least one of a plurality of terminals.

  The present invention also provides a network interface for transmitting and receiving messages in a call control device connected to a plurality of terminals via a network, a call control message for controlling a session between the plurality of terminals and the call control device, A storage device for storing a control message management table indicating a correspondence relationship with a communication type indicating whether a call control message transfer method is unicast or multicast; and one of the plurality of terminals via the network interface When the call request control message transmitted from the server is received, the communication type of the call response control message corresponding to the received call request control message and the destination terminal are determined by searching the control message management table. Controller unit The provided, based on the communication type that is determined by the control unit, via the network interface, and transmits the paging response control message to the determined terminal.

  More specifically, in the call control device of the present invention, the control message management table stores the unicast address of each terminal and the multicast address of the multicast group to which each terminal belongs. The address corresponding to the communication type is determined by searching the control message management table based on the determined communication type, and using the determined address via the network interface, The call response control message is transmitted to at least one of the plurality of terminals.

  In the present invention, the call control device (for example, PoC server) determines whether to transmit the message by unicast or multicast based on the communication type of the control message to be transmitted, and determines the one-to-one type. The control message is transmitted by unicast, and the 1 to N type control message is transmitted by multicast. In this case, the client that receives only the control message can effectively use the radio resource by releasing the air interface and using it as the radio resource of the unicast channel. In addition, since the redundant transfer of call control messages can be reduced and the consumption of network resources can be reduced, the utilization rate of cellular network resources can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of a PoC system according to the present invention.
As shown in FIG. 1, the PoC system includes a cellular network 1, a BCMCS control device 12 that is a BCMCS service device, a PoC server 11 that is a call control device, and a plurality of PoC client terminals 21, 22, and 23. . By transferring a control message such as a paging control message between the PoC client terminals 21, 22, and 23 and the PoC server 11, control of the group constituted by the PoC client terminals 21, 22, and 23 is achieved.

  A plurality of PoC client terminals 21, 22, and 23 are connected to the cellular network 1 via access terminals AT (Access Terminals) 31, 32, and 33, respectively. On the other hand, the PoC server 11 and the BCMCS control device 12 are connected to the cellular network 1 via a router (MR) 13 that supports multicast.

  The cellular network 1 includes an access point AP (Access Point), an access device (base station controller / packet control function) BSC / PCF (Base Station Controller / Packet Control Function) that supports multicast and unicast, multicast, A network device (broadcast service node) that supports unicast and BSN (Broadcast Serving Node) and a packet data service node PDSN (Packet Data Serving Node) are provided to support unicast and multicast simultaneously. . Unicast is supported by the BSC / PCF and PDSN, and multicast is supported by the PCF and BSN and is managed through the BCMCS controller 12.

FIG. 2 is a block diagram of the PoC server 11 shown in FIG.
As shown in FIG. 2, the PoC server 11 transmits a message such as a call response control message to the outside, and receives a message such as a call request control message from the outside, and a central processing unit ( CPU) 211, a storage device (hard disk) 212 in which a signaling management table (that is, a control message management table) is stored, a memory 213 in which the control unit 201 is stored, and a bus line 214 that connects these elements. . The control unit 201 includes a signaling transfer control module 202 and a token control module 203.

  In the following description, the call request control message and the call response control message used for control are collectively referred to as “call control message”. Further, as necessary, messages such as a call request control message and a call response control message are referred to as “signaling messages” and simply abbreviated as “signaling”.

FIG. 3 shows an example of detailed contents of the signaling management table 204 shown in FIG.
As shown in FIG. 3, the signaling management table 204 includes a call control message management table 301, a multicast address management table 302, and a unicast address management table 303.

  The control message management table 301 includes a TBCP message (that is, a call control message) for controlling a session established between the plurality of PoC client terminals 21, 22, 23 and the PoC server 11, and a plurality of PoC clients. A communication type indicating a TBCP message transfer method between the terminals 21, 22, 23 and the PoC server 11 is stored in association with each other.

  As shown in the control message management table 301 of FIG. 3, the TBCP message includes a TBCP rejection message issued when the PoC server rejects the token request of the PoC client terminal, a TBCP idle message indicating token idle, and a token. A request for a TBCP private message indicating that it has been occupied, a TBCP cancellation message for notifying the PoC client terminal that acquired the token from the PoC server that transmission of the voice data flow has been stopped, and a TBCP request message sent from the PoC client terminal TBCP request queue status response message for notifying the position in the queue, TBCP off message for notifying the session end of the PoC client terminal, and PoC client Such TBCP on message for notifying the session subscription preparative terminal includes.

  The communication types include two types of “1 to 1” communication and “1 to N (plurality)” communication. When a TBCP message is transmitted only to one PoC client terminal, the communication type of the TBCP message is “one-to-one”, that is, the transfer method is unicast. When a TBCP message is transmitted to a plurality of PoC client terminals, the communication type of the TBCP message is “1 to N”, that is, the transfer method is multicast.

  The multicast address management table 302 stores a correspondence relationship between a group identifier of a multicast group to which each PoC client terminal belongs and a transfer address (that is, a multicast address) corresponding to the group identifier. When the PoC server transmits a “one-to-N” type TBCP message to a plurality of PoC client terminals, the multicast address that becomes the forwarding address of the group to which the plurality of PoC client terminals belong from the multicast address management table 302 And applying the multicast address, a “1 to N” type TBCP message is transmitted to a plurality of PoC client terminals.

  The unitycast address management table 303 stores a correspondence relationship between the group identifier of the multicast group to which each PoC client terminal belongs, the identifier of the PoC client terminal, and the unicast transfer address. When the PoC server transmits a “one-to-one” type TBCP message to one of a plurality of PoC client terminals in a multicast group, the PoC server searches the unicast address management table 303 and transfers the PoC client terminal. A unicast address which is an address is acquired, and a “one-to-one” type TBCP message is transmitted to the PoC client terminal by applying the unicast address.

The control unit 201 shown in FIG. 2 transfers, for example, a plurality of types of call control messages in a session established between the plurality of PoC client terminals 21, 22, 23 and the PoC server 11 shown in FIG. Control.
When the PoC server 11 receives a paging request control message transmitted from one of the plurality of PoC client terminals 21, 22, 23 via the network interface 210, the control unit 201 searches the signaling management table 204. Thus, the communication type of the call response control message corresponding to the received call request control message is determined, and based on the content of the call response control message, which PoC client terminal is to be transmitted is determined.

  Based on the call request control message from the PoC server, the token control module 203 determines a call response control message corresponding to the call request control message to be returned to the PoC server, and sends the call response control message to the signaling transfer control module. 202 is notified.

  The signaling transfer control module 202 searches the call control message management table 301 stored in the signaling management table 204 in the hard disk, and determines the communication type of the call response control message. Further, based on the retrieved communication type, the multicast address management table 302 and the unicast address management table 303 are retrieved to determine the transfer address corresponding to the communication type of the call response control message. That is, the PoC client terminal to which the call response control message is transmitted is determined.

FIG. 4 shows a processing flowchart of the signaling transfer control module 202 in the control unit 201 of the PoC server 11.
When the signaling transfer control module 202 receives the call response control message transmitted from the PoC server 11 to the PoC client terminal (step 501), the signaling transfer control module 202 searches the call control message management table 301 and determines whether the communication type of the call response control message is multicast. It is determined whether or not (step 502).

  When the result of determination in step 502 is “NO”, that is, when the communication type of the call response control message is “one-to-one”, the signaling transfer control module 202 searches the unicast address management table 303 to A unicast address of the PoC client terminal that is the destination of the call response control message is acquired (step 504), and the call response control message is transferred by applying the unicast address (step 505).

  If the result of determination in step 502 is “YES”, that is, if the communication type of the call response control message is “1 to N”, the signaling transfer control module 202 searches the multicast address management table 302 and searches for the call response. A multicast address for transmitting the control message to all PoC client terminals is acquired (step 503), and the call response control message is transferred by applying the multicast address (step 505).

FIG. 5 shows a signaling process of the PoC system according to the present invention.
The PoC client terminal acquires a token or releases a token by transmitting a control message such as a call request control message to the PoC server via the network. The PoC server controls the token state and transmits a control message such as a call response control message to the PoC client terminal to notify the client terminal of the token state.

  In FIG. 5, a solid line arrow indicates a unicast signaling message, a two-dot chain line arrow indicates a multicast signaling message, and a broken line arrow indicates a media flow. The PoC client terminal 21 first establishes a session with the PoC server 11 according to the SIP protocol. The PoC client terminal 21 that has established the session can request a token from the PoC server 11 by transmitting a call request control message.

  As shown in FIG. 5, the PoC client terminal 21 transmits a TBCP request message, which is a call request control message, to the PoC server 11 by unicast (401). Upon receiving the TBCP request message, the PoC server 11 checks whether or not the token is occupied by other PoC client terminals 22 and 23 (402). If the token is not occupied, the PoC server 11 transmits a TBCP authorization message, which is a call response control message, to the PoC client terminal 21 in response to the TBCP request message (404). At this time, the PoC server 11 transmits a TBCP occupation message that is a call response control message to all other PoC client terminals 22 and 23 (405), and notifies that the token is currently occupied. .

  Before the call response control message is transmitted from the PoC server 11, the control unit 201 searches the call control message management table 301 to determine the communication type of the call response control message corresponding to the TBCP request message ( 403). For example, when it is determined that the communication type of the TBCP authorization message is “one-to-one”, the TBCP authorization message is transmitted to the PoC client terminal 21 by unicast. When it is determined that the communication type of the TBCP occupation message is “1 to N”, the TBCP occupation message is transmitted to the PoC client terminals 22 and 23 by multicast.

When receiving the TBCP authorization message, the PoC client terminal 21 transmits a media flow such as an audio flow to the PoC server 11. On the other hand, when receiving the TBCP occupation message, the PoC client terminals 22 and 23 receive the media flow from the PoC client terminal 21 transferred by the PoC server 11 (406).
When the PoC client terminal 21 ends the transmission of the media flow such as the voice flow and releases the token, it transmits a TBCP release message, which is a call request control message, to the PoC server 11 by unicast (407). .

  When the PoC server 11 receives the TBCP release message, the PoC server 11 checks the status of the token (408), and notifies all PoC client terminals 21, 22, and 23 of the TBCP idle message that is a call response control message. At this time, the control unit 201 searches the call control message management table 301 and confirms the communication type of the TBCP idle message (409). For example, when it is confirmed that the communication type of the TBCP idle message is “1 to N”, the PoC server 11 forwards the TBCP idle message to the PoC client terminals 21, 22, and 23 by multicast. (410).

  As described above, according to the present embodiment, for the client that receives only the call control message, the air interface is released and used as the radio resource of the unicast channel. Can be reduced. Further, since the PoC server controls the communication type of the call control message as described above to reduce the redundant transfer of the call control message in the network, the resource consumption is suppressed, and the cellular network resource utilization rate is reduced. Can be improved.

The preferred embodiments of the call control device and the call control method of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments. The present invention can be appropriately modified depending on the situation.
For example, in the above embodiment, a network configuration including three PoC client terminals and one PoC server has been described. However, it is obvious that the number of PoC client terminals and PoC servers can be arbitrarily set. In the above embodiment, the control unit 201 is composed of a signaling transfer control module and a token control module. However, if the signaling transfer control function and the token control function can be realized, the configuration modules of the control unit 201 are integrated into one. Alternatively, it may be divided into three or more modules.

  In the above embodiment, the signaling management table (control message management table) stored in the hard disk (storage device) 212 includes a call control message management table, a unicast address management table, and a multicast address management table. However, in the present invention, it is only necessary to obtain the transfer method or transfer address of the call control message communicated between the PoC client terminal and the PoC server by searching the signaling management table. It may be integrated into one table or divided into three or more sub tables. Further, the information items stored in the table may be changed as necessary.

  In the above-described embodiment, the call response control message transmitted from the PoC server to the PoC client terminal is stored in the control message management table. However, the control message management table stores, for example, from the PoC client terminal to the PoC server. Other control messages may be stored as required, such as a call request control message to be transmitted.

  The present invention can also be applied to other group communications other than the PoC system. For example, when the present invention is applied to a wireless video conference system, the utilization rate of system resources can be improved, and the present invention can be widely applied to industries.

The block diagram of the PoC system structure concerning this invention. The block diagram of the PoC server shown in FIG. The figure which shows one Example of the signaling management table shown in FIG. The flowchart of the signaling transfer control function of the PoC server shown in FIG. The signaling flowchart of the PoC system shown in FIG.

Explanation of symbols

1: cellular network, 11: PoC server, 12: BCMCS control device, 21, 22, 23: PoC client terminal, 201: control unit,
202: Signaling transfer control module, 203: Token control module,
204: Signaling management table 210: Network interface
212: hard disk, 213: memory, 214: bus line,
301: Call control message management table,
302: Multicast address management table,
303: A cast address management table.

Claims (8)

A call control method executed by a call control device connected to a plurality of terminals via a network,
A reception step of receiving a call request control message transmitted from one of the plurality of terminals via the network interface of the call control device;
A call control message for controlling a session between the plurality of terminals and the call control device, which is stored in the storage device of the call control device, and whether a transfer method of the call control message is unicast or multicast. A confirmation step for determining a communication type and a destination terminal of a call response control message corresponding to the received call request control message by searching a control message management table indicating a correspondence relationship with a communication type representing
A call control method for a call control device, comprising: a step of transmitting the call response control message to the determined terminal via the network interface based on the communication type. The call control method according to claim 1,
The control message management table further stores a unicast address of each terminal of the plurality of terminals and a multicast address of a multicast group to which each terminal belongs,
In the determining step, the address corresponding to the communication type is determined by searching the control message management table based on the communication type,
In the transmission step, the call control device transmits the call response control message to at least one of the plurality of terminals via the network interface using the determined address. Call control method. The call control method according to claim 2,
In the transmission step, when the communication type is unicast, the unicast address management table storing the unicast address of each terminal included in the control message management table is searched to search for a unicast address corresponding to the communication type. If the communication type is multicast and the communication type is determined by searching the multicast address management table storing the multicast address of the multicast group to which each terminal belongs included in the control message management table. A call control method for a call control device, wherein a corresponding multicast address is determined. A call control device connected to a plurality of terminals via a network,
A network interface for sending and receiving messages to and from the outside,
A control message indicating a correspondence between a call control message for controlling a session between the plurality of terminals and the call control device, and a communication type indicating whether a transfer method of the call control message is unicast or multicast. A storage device for storing the management table;
When a call request control message transmitted from one of the plurality of terminals is received via the network interface, the received call request control message is obtained by searching the control message management table. A control unit for determining a communication type and a destination terminal of a corresponding call response control message,
The call control device, wherein the call response control message is transmitted to the determined terminal via the network interface based on the communication type determined by the control unit. The call control device according to claim 4,
The control message management table further stores a unicast address of each terminal and a multicast address of a multicast group to which each terminal belongs,
The control unit determines an address corresponding to the communication type by searching the control message management table based on the determined communication type, and uses the determined address to configure the network interface. A call control device that transmits the call response control message to at least one of the plurality of terminals via a route. The call control device according to claim 5,
The control message management table includes a call control message management table storing a correspondence relationship between a call control message and a communication type, a unicast address management table storing a unicast address of each terminal, and each terminal belongs to the control message management table. A multicast address management table that stores a multicast address of the multicast group,
When the determined communication type is unicast, the control unit determines a unicast address corresponding to the communication type by searching the unicast address management table, and the determined communication type is multicast. In this case, the call control device determines the multicast address corresponding to the communication type by searching the multicast address management table. The call control device according to claim 6,
The control unit comprises a token control module and a signaling transfer control module;
The token control module determines a call response control message corresponding to the call request control message based on the call request control message, and notifies the signaling transfer control module of the call control message;
The signaling control module determines the communication type of the call response control message by searching the call control message management table, and determines the address corresponding to the communication type by searching the address management table. A call control device characterized by the above. The call control device according to any one of claims 4 to 7,
The call control device, wherein the call control device is a PoC server.

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