JP2006180372A - IP telephone call system and call control server for communication terminals not always connected to IP network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and a call control server capable of making an IP phone call to a communication terminal that cannot be always connected to an IP network, such as a communication terminal for a mobile communication network.
When there is no registration information of the communication terminal in response to a call request to the communication terminal, the call control server exchanges a registration request signal for requesting the communication terminal to register with the call control server. Means for transmitting to the network, and means for performing call connection processing via the IP network to the communication terminal after the communication terminal has registered via the IP network. The registration request signal received from the communication terminal is transmitted to the communication terminal.
[Selection] Figure 1

Description

  The present invention is a system that enables outgoing calls via an IP network, that is, outgoing calls via an IP telephone, to a communication terminal that is not always connected to an IP network, such as a communication terminal for a mobile communication network. And a call control server.

  Conventionally, the telephone service has been provided by a communication network based on circuit switching. However, with the spread of the Internet, an IP telephone service based on packet switching has begun to be provided.

FIG. 4 is a sequence diagram for explaining outgoing / incoming calls by IP telephone between terminals connected to the IP network. In FIG. 4, the call control server is a device that performs IP telephone call control, and each message shown in FIG. 4 is based on SIP (Session Initiation Protocol, see Non-Patent Document 1).
(S41) The terminal A transmits a Register message to the call control server in order to register information for the call control server to access the terminal A in the call control server. The call control server transmits a 200 ok message to the terminal A in order to notify the end of the registration process after the registration process of the access information to the terminal A.
(S42) Similarly, the terminal B performs registration processing with the call control server.
(S43) In order to make a call to the terminal B, the terminal A transmits an Invite message including information specifying the terminal B, such as an e-mail address and a telephone number, to the call control server. The call control server sends an Invite message to the terminal B based on the registered access information to the terminal B and notifies the terminal B of the incoming call. In addition, the call control server and the terminal B that have received the Invite message transmit Trying messages to the terminal A and the call control server that are the transmission sources of the request, respectively, to indicate that the requested processing is being executed.
(S44) The terminal B transmits a Ringing message to notify the caller that the incoming call is being displayed by ringing or vibration.
(S45) In order to indicate that the terminal B has responded, the terminal B transmits a 200 ok message.

  As can be seen from the above sequence, in order to transmit an incoming call to a certain terminal, it is necessary to register access information for the terminal in advance in the call control server. If the connection environment to the IP network is a constant connection environment such as ADSL or CATV, when the communication terminal is activated, registration processing to the call control server can be performed at the same time. It is possible to receive an incoming call by an IP phone while it is in the office.

“SIP: Session Initiation Protocol”, RFC3261, June 2002

  On the other hand, currently, a communication terminal for a mobile communication network such as a mobile phone is equipped with a function for connecting to an IP network as a standard function. The communication terminal is configured to acquire an IP address when the user starts an access operation to the IP network. That is, when the access operation to the IP network is not performed (hereinafter referred to as normal time), the connection with the IP network is substantially cut off.

  In the communication terminal, for example, it is impossible to obtain an IP address at the time of activation and register it in the call control server, and therefore, it has a function of connecting to the IP network. Therefore, it is impossible to receive an incoming IP phone call.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a system and a call control server that can make an IP telephone call to a communication terminal that cannot always connect to an IP network, such as a communication terminal for a mobile communication network. And

According to the system of the present invention,
An IP telephone call system to a communication terminal connected to a circuit switched network and not always connected to the IP network, comprising a call control server connected to the circuit switched network and the IP network, In response to an outgoing request to the communication terminal, if there is no registration information of the communication terminal, the communication terminal transmits a registration request signal requesting registration to a call control server to a circuit switched network, Means for performing call connection processing via the IP network after the communication terminal has registered via the IP network, and the circuit switching network receives the registration request signal received from the call control server Is transmitted to the communication terminal.

According to another embodiment of the system of the present invention,
It is also preferable that the circuit switched network transmits the registration request signal to the communication terminal using a control line for call control.

Also, according to another embodiment of the system of the present invention,
It is also preferable that the circuit switched network has an SMS server that transmits a message using a control line to a communication terminal connected to the circuit switched network, and the call control server transmits the registration request signal to the SMS server. .

According to the call control server of the present invention,
A call control server for controlling outgoing calls of an IP telephone to a communication terminal that is connected to a circuit switching network and is not always connected to the IP network, and registers the communication terminal in response to a call request to the communication terminal If there is no information, a means for transmitting a registration request signal for requesting registration to the call control server to the communication terminal via a circuit switching network, and after the communication terminal performs registration via the IP network, the communication And a means for performing a call connection process to the terminal via the IP network.

  A communication terminal that is not connected to the IP network is requested to register with the call control server via the circuit switching network, and after the connection to the IP network is established by the communication terminal, the call control server is contacted. In this configuration, it is possible to make a call by IP telephone to a communication terminal that is not always connected to the IP network.

  The registration request is configured to be transmitted to the communication terminal through the control line between the circuit switching network and the communication terminal, so that the line setting between the call control server and the communication terminal is not actually required. A signal requesting registration quickly can be transmitted to the communication terminal.

  By making the best use of existing systems, the cost required for implementation can be reduced.

  The best mode for carrying out the present invention will be described in detail below with reference to the drawings.

  FIG. 1 is a diagram illustrating an embodiment of a system according to the present invention. According to FIG. 1, the system includes a communication terminal 1, a call control server 2, a circuit switching network 3, an IP network 4, and a communication terminal 5 connected to the IP network 4.

  The circuit switching network 3 is a communication network based on circuit switching and used for a conventional telephone network, and the IP network 4 is a communication network based on packet switching, such as the Internet protocol.

  The call control server 2 is a device that performs call control processing such as line setting / disconnection between communication terminals connected to an IP network, for example, a SIP server. Further, the call control server 2 is connected to the circuit switching network 3.

  The communication terminal 1 has a function of performing communication by connecting to both the circuit switching network 3 and the IP network 4 like a communication terminal for a mobile communication network, but normally connected to the IP network 4. An IP address or the like for communication is not assigned, and information cannot be received via the IP network 4. In other words, as shown by the solid line 13 in FIG. 1, since it is connected to the circuit switching network 3, it is possible to make and receive calls via the circuit switching network 3, but the dotted line 14 As shown, the IP network 4 is not substantially connected.

  The communication terminal 1 is connected to the IP network 4 when the user needs to connect to the IP network 4 as in the case where the user performs an access operation to the IP network 4. Yes, in this case, the communication terminal 1 acquires information necessary for communication via the IP network 4 such as an IP address from the IP network 4.

  FIG. 2 is a schematic diagram illustrating the configuration of the circuit switching network 3. The circuit switching network 3 includes an SMS server 31 and a plurality of exchanges 32. The exchange 32 has an exchange function for setting a line between communication terminals connected to the line exchange network 3.

  The SMS server 31 is connected to the exchange 32 and has a function of transmitting various messages to the communication terminal 1 via the exchange 32 via a control line that is a transmission line for control signals for call control. The SMS server 31 is connected to the call control server 2.

  FIG. 3 is an IP telephone call sequence diagram from the communication terminal 5 connected to the IP network 4 to the communication terminal 1 not always connected to the IP network 4. It is assumed that the communication terminal 5 has already completed registration processing with the call control server 2.

  (S31) The communication terminal 5 transmits an Invite message including information identifying the communication terminal 1 such as the telephone number of the communication terminal 1 to the call control server 2 in order to make a call via the IP network to the communication terminal 1. Since the call control server 2 does not have registration information of the communication terminal 1 itself, the call control server 2 transmits a registration request signal including information for identifying the communication terminal 1 to the circuit switching network 3. The registration request signal transmitted by the call control server 2 is received by the SMS server 31, and the SMS server 31 uses the control line to determine the communication terminal based on the information specifying the communication terminal 1 included in the received registration request signal. 1 sends a registration request signal. The communication terminal 1 that has received the registration request signal transmits a response signal to the SMS server 31 for confirmation of reception, and similarly, the SMS server 31 transmits a response signal to the call control server 2. Further, the call control server 2 transmits a Trying message to the communication terminal 5 that is the transmission source of the request in order to indicate that the call setting process for the requested communication terminal 1 is being executed.

  (S 32) The communication terminal 1 that has received the registration request signal from the circuit switching network 3 acquires information necessary for communication via the IP network 4, such as an IP address, from the IP network 4 and connects to the IP network 4. Put it in a state.

  (S33) The communication terminal 1 connected to the IP network performs a registration process for the call control server 2.

  (S34) Upon completion of the registration process of the communication terminal 1, the call control server 2 transmits an Invite message to the communication terminal 1 via the IP network 4, and notifies the communication terminal 1 of an incoming call from the communication terminal 5. Thereafter, line setting is performed in the sequence already described.

  As described above, an IP telephone can be transmitted via the IP network 4 to a communication terminal that is not always connected to the IP network 4. In addition, since the registration request signal is transmitted to the communication terminal 1 through the control line between the circuit switching network and the communication terminal 1, the line between the call control server 2 and the communication terminal 1 is actually used. The configuration does not require setting.

  Further, the SMS server 31 is used for a short message service of an existing mobile communication network, and the cost required for implementation can be reduced by utilizing the existing system to the maximum extent. .

It is a figure explaining embodiment of the system by this invention. It is the schematic explaining the structure of a circuit switching network. FIG. 3 is an IP telephone call sequence diagram from a communication terminal connected to an IP network to a communication terminal not always connected to the IP network. It is a sequence diagram explaining the outgoing / incoming call by the IP telephone between the terminals connected to the IP network.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 5 Communication terminal 2 Call control server 3 Circuit switching network 4 IP network 13 Link with circuit switching network 14 Link with IP network 31 SMS server 32 Switch

Claims (4)

A system for connecting an IP telephone to a communication terminal that is connected to a circuit switched network and is not always connected to the IP network,
A call control server connected to a circuit switched network and an IP network;
The call control server
In response to a call request to the communication terminal, if there is no registration information of the communication terminal, the communication terminal transmits a registration request signal for requesting registration to a call control server to a circuit switched network;
Means for performing call connection processing via the IP network to the communication terminal after the communication terminal has registered via the IP network;
Circuit switched network
A system comprising means for transmitting the registration request signal received from a call control server to the communication terminal.   The system according to claim 1, wherein the circuit switching network transmits the registration request signal to the communication terminal using a control line for call control. The circuit switching network has an SMS server that transmits a message using a control line to a communication terminal connected to the circuit switching network.
The system according to claim 2, wherein the call control server transmits the registration request signal to an SMS server. A call control server for controlling outgoing calls of an IP phone to a communication terminal that is connected to a circuit switched network and is not always connected to the IP network,
In response to the transmission request to the communication terminal, if there is no registration information of the communication terminal, means for transmitting a registration request signal for requesting registration to a call control server to the communication terminal via a circuit switching network;
Means for performing call connection processing via the IP network to the communication terminal after the communication terminal has registered via the IP network;
A call control server comprising:

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