JP2008252608A - Satellite communication method, slave station, and master station - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a satellite communication method, a slave station, and a master station that can perform address registration processing, origination/termination processing, etc., of an IP telephone when communication by the IP telephone connected to the slave station is performed through a DAMA type satellite communication line. <P>SOLUTION: Based upon an Invite message sent from the IP telephone connected to the slave station 2, an Invite control signal conforming to a DAMA type control signal format is generated, and transmitted from the slave station 2 to the master station 1 through an up CSC line. The master station 1 retrieves address information on an opposite IP telephone from a SIP server device, generates an Invite control signal based upon a retrieval result, and transmits it to an opposite-side slave station through a down CSC line. The opposite slave station reproduces the Invite message based upon the Invite control signal, and transmits it to the opposite IP telephone. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a satellite communication method, a slave station, and a master station that perform voice and data communications of a terminal device including an IP telephone connected to a slave station by satellite communication of a request allocation multiple access method via a satellite. .

  Due to the recent development of Internet communication, data communication via the Internet has been actively performed, and voice communication via the Internet is also becoming widespread supported by IP telephone system construction technology. The voice communication over the Internet by this IP phone is different from the other data communication because of the simultaneity that the voice communication should have, and a protocol suitable for each signaling process of the start, change and end of the voice communication is necessary. is there. As a typical protocol, there is SIP (Session Initiation Protocol) defined in the RFC3261 standard and related standards, and various services such as an IP phone are provided by this protocol in the application layer. On the other hand, in the field of satellite communications, a request allocation multiple access scheme (hereinafter referred to as “DAMA scheme”) is used from the fixed scheme communication between one-to-one satellite communications apparatuses. DAMA is an abbreviation for Demand Assignment Multiple Access. )), And further communication by satellite mobile phones using CDMA or FDMA schemes such as the Iridium Project. Satellite communication has a history of technological development different from wired communication on the ground, from the viewpoint of wide area and publicity, and by pursuing the establishment of communication based on the speciality of remote wireless communication.

  The DAMA system in satellite communication is a system for effectively using a satellite communication line by a plurality of slave stations, and appropriately assigns a communication line used for communication between slave stations or between slave stations / parent stations. A communication line assignment request is issued from a slave station on a control line (referred to as “CSC line”) different from the communication line, the master station receives the line assignment request, and the master station assigns the communication line. Is. In JP-A-10-51370, in a DAMA satellite communication system, when a telephone terminal is connected to a slave station and voice communication is performed by telephone between the slave stations, a unique number of the telephone terminal is assigned to the master station. There is disclosed a conventional technique in which a slave station data file in which at least a part, for example, 03 (Tokyo) or 06 (Osaka) is associated with a relay station group number to be relayed is provided. According to this conventional technique, when a unique number of a partner telephone terminal is dialed from a telephone terminal connected to one slave station, the slave station uses at least a part of the unique number of the partner telephone terminal at the master station. Select the corresponding slave station from the data file and assign a satellite communication line between the slave station and the partner slave station, and specify the partner slave station when calling from the slave station There is no need to do so, and the operability is improved.

JP-A-10-51370

  As described above, for example, the SIP protocol provides a signaling process in the application layer, and various IP telephone address registration processes and processes related to session establishment occur in the communication line. In DAMA satellite communication, when an IP telephone is connected to a slave station and voice communication is performed between the slave stations via the satellite, communication lines are frequently used for such various processes. Thus, there is a problem that the use efficiency of voice and data communication on the communication line is lowered. In addition, in order to perform voice communication by IP telephone, a server device for protocol control (in SIP, a server device generally referred to as a SIP server) is required. There is a problem that it is necessary to consider that the complications of communication packets and input / output processing packets to / from the server do not reduce the utilization efficiency of the communication line via the satellite.

  The present invention has been made to solve the above-mentioned problems or problems. When a communication is performed using an IP phone connected to a slave station in a DAMA satellite communication line, an IP phone address is registered. It is an object to obtain a satellite communication method, a slave station, and a master station that can perform processing and incoming / outgoing call processing.

  According to a first aspect of the present invention, a satellite communication method requests a channel allocation from a slave station via a CSC channel via a satellite, allocates a communication channel from the master station, and performs satellite communication between the slave station and the partner slave station. In a line assignment type satellite communication method to be performed, based on a message from an IP telephone connected to the slave station, a control signal to be transmitted by the slave station via the CSC line is generated and transmitted via the CSC line. The master station that has received the control signal reproduces the message.

  The slave station according to the invention of claim 2 is requested to allocate a line via a CSC line passing through a satellite, and is connected at a slave station that is allocated a communication line by the master station and performs satellite communication with the partner slave station. A satellite GW device that generates a control signal to be transmitted through the CSC line based on a message from the IP telephone, and a satellite communication that transmits the control signal generated by the satellite GW device to the master station through the CSC line. Device.

  The slave station according to the invention of claim 3 is connected to a slave station that requests a line assignment by a CSC line passing through a satellite and is assigned a communication line by a master station and performs satellite communication with a partner slave station. Discriminating means for discriminating that the received data is a message from the IP phone from the received data from the terminal device group including the IP phone, and discriminating that the received data is a message from the IP phone A satellite GW apparatus having message processing means for generating a control signal to be transmitted by the CSC line based on the message, and a satellite communication apparatus for transmitting the control signal to the master station by the CSC line It is.

  According to a fourth aspect of the present invention, there is provided a master station for allocating a communication line for satellite communication performed between slave stations based on a channel assignment request transmitted from a slave station via a CSC line passing through a satellite. A master station satellite communication apparatus that receives the transmitted control signal via the CSC line, and a line control that reproduces a message from the IP telephone connected to the slave station based on the control signal received by the master station satellite communication apparatus Device.

  According to a fifth aspect of the present invention, there is provided a satellite communication method that requests a channel assignment from a slave station via a CSC channel passing through a satellite, assigns a communication channel from the master station, and performs satellite communication between the slave station and the partner slave station. In a line assignment type satellite communication method to be performed, a first control signal to be transmitted through the CSC line is generated and transmitted through the CSC line based on an invite message by the SIP protocol from an IP telephone connected to the slave station. Then, the master station that has received the first control signal searches for the IP address of the partner IP phone that is the destination of the invite message and the slave station number of the partner slave station to which it is connected. A second control signal is transmitted to the station via the CSC line, and the other party slave station that has received the second control signal reproduces the invite message to the other party IP phone. It is intended to be sent.

  The slave station according to the invention of claim 6 is connected to a slave station that requests a line assignment by a CSC line passing through a satellite, is assigned a communication line by a master station, and performs satellite communication with a partner slave station. Discriminating means for discriminating that the received data is an invite message by the SIP protocol from the IP phone from the received data from the terminal device group including the IP phone, and by the discriminating means using the invite message by the SIP protocol. A satellite GW apparatus having message processing means for generating a first control signal transmitted by the CSC line when it is determined to be present, and a satellite communication apparatus for transmitting the control signal to the master station by the CSC line It is equipped with.

  According to a seventh aspect of the present invention, there is provided a master station for allocating a communication line for satellite communication performed between slave stations based on a channel assignment request transmitted from the slave station via a CSC line passing through a satellite. The master station satellite communication device that receives the first control signal generated based on the SIP message invite message sent from the connected IP telephone through the CSC line, and the first station satellite communication device that receives the first control signal. Search means for searching for the IP address of the counterpart IP telephone that is the destination of the invite message and the slave station number of the counterpart slave station to which the invite message is connected based on the control signal, and transmitted to the counterpart slave station via the CSC line. And message processing means for generating a second control signal for reproducing the invite message at the counterpart slave station.

  In the satellite communication method according to the eighth aspect of the present invention, a channel assignment request is made from a slave station by a CSC line passing through a satellite, a communication line is assigned by the master station, and satellite communication is performed between the slave station and the partner slave station. In the line assignment type satellite communication method to be performed, a control line is provided separately from the CSC line and the communication line, and the slave station uses the control line on the basis of a message from an IP telephone connected to the slave station. A control signal to be transmitted is generated and transmitted through the control line, and the master station that has received the control signal reproduces the message.

  The slave station according to the invention of claim 9 is connected to a slave station that requests a line assignment by a CSC line passing through a satellite, is assigned a communication line by a master station, and performs satellite communication with a partner slave station. A satellite GW device for generating a control signal to be transmitted by a control line provided separately from the CSC line and the communication line based on the message from the IP telephone, and the control signal generated by the satellite GW device And a satellite communication device that transmits to the master station via a control line.

  According to a tenth aspect of the present invention, there is provided a master station for allocating a communication line for satellite communication performed between slave stations based on a channel assignment request transmitted from a slave station via a CSC line passing through a satellite. A master station satellite communication device that receives the transmitted control signal via a control line provided separately from the CSC line and the communication line, and a control signal received by the master station satellite communication device is connected to the slave station. And a line control device for reproducing a message from the IP telephone.

  According to the first to fourth aspects of the invention, based on the message from the IP telephone connected to the slave station, the slave station generates a control signal to be transmitted by the CSC line and transmits the control signal by the CSC line. Since the master station that has received this control signal reproduces the message, the IP telephone message can be processed without assigning a communication line.

  According to the invention described in claims 5 to 7, the first control signal to be transmitted by the CSC line is generated based on the invite message by the SIP protocol from the IP telephone connected to the slave station, and the CSC line is generated. The master station that has received the first control signal transmits the IP address of the partner IP telephone that is the destination of the invite message and the slave station number of the partner slave station to which it is connected. The second control signal is transmitted to the station via the CSC line, and the counterpart slave station that has received the second control signal reproduces the invite message and transmits it to the partner IP telephone. Invite message processing of an IP phone according to the SIP protocol can be performed.

  According to the invention described in claims 8 to 10, since the control line is provided separately from the CSC line and the communication line and the connection processing between the IP telephones connected to the slave stations is performed on the control line, the CSC It is possible to prevent the communication efficiency from being lowered due to the IP telephone connection process occurring on the line and the communication line.

Embodiment 1

  A satellite communication method, a slave station, and a master station according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a block diagram showing a configuration of a satellite communication system according to Embodiment 1 of the present invention. In FIG. 1, 1 is a master station, 2 is a slave station, 3 is a communication satellite, 4 is an uplink CSC line for transmitting a control signal from the slave station 2 to the master station 1 via the communication satellite 3, and 5 is This is a downlink CSC line for transmitting a control signal from the master station 1 to the slave station 2 via the communication satellite 3. The uplink CSC line 4 transmits a line assignment request signal for requesting communication line assignment from the slave station 2 to the master station 1, and the master station 1 assigns the communication line 6 between the slave stations. The line information of the assigned communication line 6 is transmitted from the master station 1 to the slave station 2 and the other slave station 2 as the communication partner as a line assignment response signal via the downlink CSC line 5. Communication is performed between the slave station 2 that has received this line assignment response signal and the partner slave station 2 via the communication line 6 via the communication satellite 3. This communication line 6 is also allocated for communication between the master station 1 and the slave station 2. FIG. 2 is a schematic diagram showing the arrangement of the lines used on the frequency axis. As shown in FIG. 2, the lines to be used are an uplink CSC line 4, a downlink CSC line 5, and a plurality of communication lines 6, and the uplink CSC line 4 and the downlink CSC line 5 are fixedly assigned and a plurality of communication lines are used. The line 6 is appropriately allocated by the master station 1 based on the request from the slave station 2 as described above in the frequency band allocated to the satellite communication system. The upstream CSC line 4 and the downstream CSC line 5 are originally control lines for establishing the DAMA system. When various processing signals for voice communication by an IP telephone, which will be described later, are transmitted and received on these lines, the lines become congested, and the original DAMA It can also be expected that the control will not function sufficiently. In this case, various processing signals for voice communication by IP telephone are transmitted between the slave station 1 and the master station 2 separately from the CSC line and the communication line, instead of the upstream CSC line 4 and the downstream CSC line 5. Further, a downlink control line (not shown in FIG. 2) may be provided, and transmission / reception may be performed on this control line.

  Next, the configuration of the master station 1 and the slave station 2 will be described. FIG. 3 is a block diagram showing the configuration of the slave station and the master station according to Embodiment 1 of the present invention. In the master station 1 shown in FIG. 3, reference numeral 7 denotes a master station satellite communication apparatus that performs transmission / reception of radio waves to / from the communication satellite 3, modulation / demodulation, and signal processing, 8 is a line control apparatus that performs DAMA line control and SIP processing, 9 Is a SIP server device. In the master station satellite communication device 7, reference numeral 10 denotes a transmitter / receiver that transmits / receives radio waves to / from the communication satellite 3, and performs signal frequency conversion, amplification, and the like. A CSC line modulation / demodulation unit 11 modulates / demodulates a control signal to be transmitted / received, and modulates / demodulates the control signal based on various modulation / demodulation methods such as PSK (phase shift modulation / demodulation). A signal processing unit 12 performs frame processing and error correction code processing of the transmission signal, error correction processing and frame processing of the reception signal. In the line control device 8, reference numeral 13 denotes a DAMA line control unit that performs DAMA line control. The DAMA line control unit 13 performs control processing using a control signal received from the slave station 2 through the uplink CSC line 4 and transmits to the slave station 2 through the downlink CSC line 5. The control signal to be generated is generated. Reference numeral 14 denotes an SIP message processing unit that performs processing based on the SIP message when the control signal from the slave station 2 is an SIP message. In the SIP server device 9, 15 is a registrar server that accepts a Register (register) message from the slave station 2, 16 is a location server that records registration information from the registrar server 15, and 17 is an Invite message from the slave station 2. On the other hand, it is a proxy server that inquires the location server 16 about information on the called side and transfers an invite message to the called side.

  The configuration of the slave station 2 and the connected device shown in FIG. 3 will be described. Reference numeral 18 denotes an IP terminal, reference numeral 19 denotes an IP telephone, the IP terminal 18 is a device for mainly performing data communication with the IP terminal 18 connected to the other slave station 2, and the IP telephone 19 is connected to the other child station. This is a device that mainly performs voice communication with the IP telephone 19 connected to the station 2. The IP terminal 18 and the IP telephone 19 are devices that can perform packet communication in accordance with the Internet protocol. The IP terminal 18 can also have a voice communication function, and the voice communication function of the IP terminal 18 is the present invention. It shall be included in the IP phone. The slave station 2 is also connected to another external network 22 via an interface device 20 (hereinafter referred to as I / F 20), and this connection is generally made via a proxy server 21. In the slave station 2 shown in FIG. 3, reference numeral 23 denotes a satellite communication device that performs radio wave transmission / reception, modulation / demodulation, and signal processing with the communication satellite 3, and reference numeral 24 denotes a satellite of the slave station 2 for communication by the IP terminal 18 or IP telephone 19. This is a satellite gateway device (hereinafter referred to as a satellite GW device) that performs transmission processing of data and audio data to be performed via the communication device 23. In the satellite communication device 23, reference numeral 25 denotes a transmitter / receiver that transmits / receives radio waves to / from the communication satellite 3, and performs signal frequency conversion, amplification, and the like. A CSC line modulation / demodulation unit 26 modulates / demodulates a control signal to be transmitted / received, and modulates / demodulates the control signal based on various modulation / demodulation methods such as PSK (phase shift modulation / demodulation). A communication line modulation / demodulation unit 27 modulates / demodulates a communication signal to be transmitted / received, and modulates / demodulates the communication signal based on various modulation / demodulation methods such as PSK (phase shift modulation / demodulation). A signal processing unit 28 performs frame processing and error correction code processing of the transmission signal, error correction processing and frame processing of the reception signal. A control unit 29 controls the transmission / reception frequency and band of the communication line modulation / demodulation unit 27 based on the line assignment response signal received by the CSC line modulation / demodulation unit 26. In the satellite GW apparatus 24, transmission control 30 identifies transmission data in communication by the IP terminal 18 or IP telephone 19, and transfers transmission data between the satellite communication apparatus 23, the IP terminal 18, and the IP telephone 19. 31 is a SIP processing unit that performs message processing when data to be transmitted is a message according to the SIP protocol. An identification information storage unit 32 stores identification information of the IP phone 19 included in the SIP message processed by the SIP processing unit 31.

  The configuration shown in FIG. 3 shows an example in which IP phone processing is performed by the SIP protocol, but can be replaced by a protocol that performs the same type of IP phone communication processing. For example, the SIP phone shown in FIG. The server device 9 may be a server device used to execute the protocol to be replaced, and the SIP message processing unit 14 in the master station 1 and the SIP processing unit 31 in the slave station 2 are respectively The same processing as the SIP message processing unit 14 and the SIP processing unit 31 may be performed.

  Although not shown in FIG. 3, a circuit unit corresponding to the communication line modulation / demodulation unit 27 in the satellite communication device 23 of the slave station 2 is included in the master station satellite communication device 7 of the master station 1. There is a device corresponding to the satellite GW device 24 of the slave station 2, and an IP terminal or an IP telephone connected to the master station 1 or another network device via the interface uses the master station 1 to establish a communication satellite. The communication line 6 can communicate with IP terminals connected to a plurality of slave stations. In the master station 1, a circuit and a device that perform a function provided to an IP terminal or the like may be considered to correspond to the slave station 1.

  Regarding the operations of the master station 1 and the slave station 2, the operation in the case of performing data communication via the communication satellite 3 between the IP terminals 18 connected to the slave stations will be described first. The transmission control unit 30 transmits transmission data from the IP terminal 18 to the signal processing unit 28 while buffering, and the amount of transmission data that can be transmitted to the transmission control unit 30 and the signal processing unit 28 is allocated to the satellite communication device 23. Depending on the bandwidth of the selected communication line. When the slave station 2 needs data communication with the partner slave station 2, the slave station 2 transmits a line assignment request signal to the master station 1 through the uplink CSC line 4. This line allocation request signal includes information for identifying the partner slave station, is generated by the transmission control unit 30, is signal-processed by the signal processing unit 28, is modulated by the CSC line modulation / demodulation unit 26, and is transmitted by the transceiver 25. Sent. The master station 1 monitors the upstream CSC line 4, receives and demodulates the line assignment request signal, processes the signal, and reproduces it. The data is input to the DAMA line control unit 13 reproduced by the signal processing unit 12 of the master station 2, and the DAMA line control unit 13 searches for a free area in the system dedicated band (a usable frequency band given to the communication system). A communication line is allocated to a free area, a center frequency and bandwidth information, and a line allocation response signal including information specifying the slave station 2 and the partner slave station 2 that have requested the line allocation are generated, and signal processing is performed. To the unit 12. The channel assignment response signal is signal-processed by the signal processing unit 12, modulated by the CSC channel modulation / demodulation unit 11, and transmitted from the transceiver 10 through the downlink CSC channel 5. The slave station 2 and the partner slave station 2 monitor the downlink CSC line 5 and, upon receiving the line assignment response signal, demodulate and reproduce it, and set the communication line modulation / demodulation unit 29 to the assigned center frequency and bandwidth. Set to communicate between slave stations. The communication line assigned here is a transmission line from the slave station 2 to the partner slave station 2 and a transmission line from the partner slave station 2 to the slave station 2. When communication between the slave stations 2 is completed, a transmission end signal is generated by the transmission control unit 20 of the slave station 2 and transmitted to the master station 2 via the upstream CSC line 4, and the master station 2 has assigned the communication line. To free space in the system dedicated band. Communication between the slave stations 2 is not only performed between a pair of IP terminals 18 but also between a plurality of pairs of IP terminals 18 between the slave stations 2. The amount of data transmission increases or decreases. When the data transmission amount increases or decreases, the transmission control unit 30 of the slave station 2 generates a band change request signal and transmits it via the uplink CSC line 4. The master station 2 receives the band change request signal and receives the DAMA The communication line may be reassigned by the line control unit 13. The DAMA line control unit 13 of the master station 2 generates a line reassignment response signal and transmits it via the downlink CSC line 5, and the slave station 2 and the partner slave station 2 that have received this change the communication frequency band. Such reallocation of communication lines allows flexible operation of the system dedicated band. When the master station 1 starts communication with the slave station 2, the line assignment is performed directly by the DAMA line control unit 13 of the master station 1, and a line assignment response signal is sent to the partner slave station 2 and the CSC line 5 May be transmitted.

  Next, the operation of the master station 1 and the slave station 2 will be described when voice communication is performed via the communication satellite 3 between the IP telephones 19 connected to the slave stations. Before the IP telephone 19 starts voice communication based on the SIP protocol, information of the IP telephone 19 such as an IP address that is statically or dynamically assigned when the IP telephone 19 is connected to the slave station 2 is obtained from the master station 1. It is assumed that it is registered in the SIP server device 9. This registration process is performed by a registration request from the slave station 2 to the master station 1 on the basis of the Register message from the IP phone 19, and the master station 1 accepts the registration process by the registrar server 15 in the SIP server device 9, and Information such as the IP address of the IP phone 19 is registered in the server 16. The registered information includes the SIP URI of each IP phone 19, the IP address, and the slave station number of the slave station 2 to which it belongs. If the location server 16 cannot store such a correspondence, the SIP URI and IP address of the IP phone 19 are registered in the location server 16 and the SIP URI of the IP phone 19 is registered in the SIP message processing unit 14. , And the slave station number to which it belongs. The registration request from the slave station 2 to the master station 1 can be generated by, for example, creating a control signal for registration in the slave station 2 and transmitting it to the master station 1 via the uplink CSC line 4. 1 can be executed without allocating the communication line 6 to 1.

  Next, processing when a call signal (or call message) specifying the other party's IP phone 19 is issued from the IP phone 19 will be described. Of the processes for the call signal issued from the IP telephone 19, the process when an Invite message according to the SIP protocol is issued will be described below as an example. FIG. 4 is a processing sequence diagram showing processing for the Invite message. When the operator of the IP phone 19 dials the other party in step S1, an invite message is generated in the IP phone 19, and is transmitted to the transmission control unit 30 in the satellite GW apparatus 24 in step S2. The Invite message at this stage is set to, for example, the IP address of the SIP server device 9 in the master station 1 because the IP address of the partner IP phone 19 is unknown. The transmission control unit 30 in the satellite GW apparatus 24 identifies the SIP message issued by the IP telephone 19 from the data transmitted in the transport layer, and transfers it to the SIP processing unit 31. As an example of this identification method, a method of identifying based on packet description contents (contents such as an IP address, a port number, and a protocol number) according to a transport layer protocol is conceivable. That is, the destination address, port number, and protocol number of the Invite message issued by the IP phone 19 have specific values (for example, the IP address of the SIP server device 9 in the master station 1, the IP address of the slave station 2, the multicast address, etc.) By detecting this specific value based on the fact that it is indicated, it can be identified as a SIP message. The SIP message is generally composed of a request line, a status line, a header part, a blank line, and a body part. A SIP protocol specific description described in the request line, the header part, etc., for example, Register, Invite, SIP, etc. The transmission control device 30 may be transmitted from the terminal device group including the IP terminal 18 and the IP telephone 19 by various methods by detecting the description of the version or the like. Of the incoming packets, the packet from the IP telephone 19 can be identified as a SIP message. The SIP processing unit 31 detects “Invite” described in the request line of the content of the Invite message transferred from the transmission control unit 30 and inquires the IP address of the partner IP phone 19 via the upstream CSC line 4. An Invite control signal is generated. This Invite control signal is obtained by converting the Invite message into a DAMA control signal format, and the local station ID, signal identification, signal length, local station number of the local station, and the SIP URI of the partner IP phone 19 are displayed. Shall be included. The signal identification is a code indicating that the control signal is an Invite message among SIP messages. Hereinafter, a signal conforming to the SIP protocol is referred to as “˜message”, and a DAMA control signal is referred to as “˜control signal”. In addition, the SIP processing unit 31 includes information necessary for subsequent SIP message processing (the SIP URI of the IP phone 19 that made the call, the domain name, the IP address of the proxy server, the serial number of the IP phone 19 in the slave station, the other party) Information such as SIP URI of the IP phone) is output to the identification information storage unit 32. When the data length of the Invite control signal is longer than the data length allowed for one control signal in the uplink CSC line 4, the data may be transmitted by being divided into a plurality of control signals. The Invite control signal is transmitted from the transceiver 25 via the transmission control unit 30, the signal processing unit 28, and the CSC line modulation / demodulation unit 26 via the uplink CSC line 4 in step S3 shown in FIG.

  The master station satellite communication device 7 receives the Invite control signal through the uplink CSC line 4, demodulates and processes the signal, and outputs it to the line control device 8 in step S4. The SIP message processing unit 14 in the line control device 8 reproduces the Invite message including the SIP URI of the partner IP phone 19 based on the Invite control signal, and outputs it to the proxy server 17 in the SIP server device 9 in step S5. The proxy server 17 receives the Invite message and inquires the location server 16 to search for the IP address corresponding to the SIP URI of the partner IP phone 19 and the slave station number to which the partner slave station 19 is connected. The location server 16 returns the IP address and slave station number of the partner IP phone 19 to the proxy server 17, and the proxy server 17 generates a response message including the IP address and slave station number of the partner IP phone 19, The message is output to the SIP message processing unit 14 through S6. The SIP message processing unit 14 generates an Invite control signal based on the response message from the proxy server 17, and outputs it to the master station satellite communication device 7 in step S7. This Invite control signal includes the signal identification, the source slave station number, the signal length, the slave station number of the partner slave station, the SIP URI and IP address of the partner IP phone 19. When the data length is long, the Invite control signal may be divided into a plurality. The master station satellite communication device 7 transmits the Invite control signal input from the SIP message processing unit 14 to the partner slave station via the downlink CSC line 5 in step S8. In the partner slave station 2, the satellite communication device 23 receives the Invite control signal through the downlink CSC line 5, the satellite GW device 24 reads the IP address of the partner IP phone 19 from the Invite control signal, and restores the Invite message using the SIP protocol. In step S 9, the Invite message is transmitted to the partner IP phone 19.

  A series of processing is performed by converting an Invite message in accordance with the SIP protocol issued by the IP telephone 19 connected to the slave station 2 into an Invite control signal for a DAMA CSC line in the satellite GW device 24 of the slave station 2 and then performing an uplink CSC. The message is transmitted to the master station 1 via the line 4, and the Invite message according to the SIP protocol is reproduced in the master station 1, and the SIP server device 9 is inquired about the IP address of the partner IP phone. After that, based on the response message from the SIP server device 9, an Invite control signal based on the DAMA method specifying the partner slave station is generated, transmitted to the partner slave station 2 via the downlink CSC line 5, and the partner slave station 2 performs the Invite control. The Invite message according to the SIP protocol is reproduced from the signal and transmitted to the partner IP phone 19. By this processing, the Invite message can be transferred without assigning the communication line 6 on the satellite line, and the communication line 6 can be suppressed from being assigned every time the SIP message occurs.

  After transmitting the Invite control signal in Step S8, the master station 1 generates 100Trying as a response message by the SIP server device 9 in Step S10, and generates a response control signal (100Trying) in the SIP message processing unit 14. In step S11, the data is output to the master station satellite communication device 7. In step S12, the master station satellite communication device 7 transmits a response control signal (100 Trying) to the calling side slave station 2 through the downlink CSC line 5. In the slave station 2, the satellite communication device 23 receives the response control signal (100Trying), reproduces the response message (100Trying), and transmits it to the IP telephone 19 that originated the call in step S13.

  On the other hand, in response to the Invite message received by the partner IP phone 19 in step S9, the partner IP phone 19 transmits a response message of 180 Ringing to the partner slave station 2 in step S14. The satellite GW apparatus 24 of the partner slave station 2 generates a response control signal (180 Ringing) based on the response message (180 Ringing), and transmits it to the master station 2 via the uplink CSC line 4 in step S15. The master station satellite communication device 7 receives and demodulates the response control signal (180 Ringing) through the uplink CSC line 4 and outputs it to the line control device 8. The SIP message processing unit 14 in the line control device 8 generates a response message (180 Ringing) based on the response control signal (180 Ringing) and outputs the response message to the SIP server device 9, and the proxy server 17 sends the response message to the calling side. The SIP message processing unit 14 again generates a response control signal (180 Ringing) and transmits it to the calling side slave station 2 via the downlink CSC line 5 in step S16. The satellite GW apparatus 24 in the calling side slave station 2 generates a response message (180 Ringing) based on the received and demodulated response control signal (180 Ringing), and transmits it to the calling side IP phone 19 in step S18. In the IP telephone on the calling side, it can be seen from this response message (180 Ringing) that the other party's IP telephone is being called.

  When the partner IP phone 19 responds to the call, the partner IP phone 19 generates a 200 OK response message, and this response message is transmitted from the partner IP phone 19 to the partner slave station 2 in step S19. The satellite GW apparatus 24 of the partner slave station 2 generates a response control signal (200 OK) based on the response message (200 OK), and transmits it to the master station 2 via the uplink CSC line 4 in step S20. The master station satellite communication device 7 receives and demodulates the response control signal (200 OK) through the uplink CSC line 4 and outputs it to the line control device 8. The SIP message processing unit 14 in the line control device 8 generates a response message (200 OK) based on the response control signal (200 OK), and outputs the response message to the SIP server device 9. The response message is sent to the calling side by the proxy server 17. The SIP message processing unit 14 again generates a response control signal (200 OK), and transmits it to the calling side slave station 2 via the downlink CSC line 5 in step S21. The satellite GW apparatus 24 in the calling side slave station 2 generates a response message (200 OK) based on the received and demodulated response control signal (200 OK), and transmits it to the calling side IP phone 19 in step S22. In the IP telephone on the calling side, it can be seen from this response message (200 OK) that the other party IP telephone 19 has accepted the call.

  Upon receiving the response message (200 OK) in step S22, the calling IP phone 19 generates a response message (Ack) and transmits it to the slave station 2 in step S23. The satellite GW apparatus 24 of the slave station 2 generates a response control signal (Ack) based on the response message (Ack), and transmits it to the master station 2 via the uplink CSC line 4 in step S24. The master station satellite communication device 7 receives and demodulates the response control signal (Ack) via the uplink CSC line 4 and outputs it to the line control device 8. The SIP message processing unit 14 in the line control device 8 generates a response message (Ack) based on the response control signal (Ack) and outputs the response message to the SIP server device 9. The proxy server 17 sends the response message to the partner IP phone. The SIP message processing unit 14 again generates a response control signal (Ack), and transmits the response control signal (Ack) to the partner slave station 2 via the downlink CSC line 5 in step S25. The satellite GW apparatus 24 in the partner slave station 2 generates a response message (Ack) based on the received and demodulated response control signal (Ack), and transmits it to the partner IP phone 19 in step S26. In the other party IP telephone 19, it can be seen from this response message (Ack) that voice communication between IP telephones has started.

  As described above, the SIP message (request message and the above-mentioned various response messages) until the start of voice communication after the IP telephone calling operation by the Invite message is transmitted on the uplink CSC line 4 and the line via the satellite. Since transmission / reception is performed using the downlink CSC line 5, these processes can be performed without newly allocating the communication line 6, so that the communication line 6 is prevented from being assigned every time a SIP message occurs. be able to.

  In addition, various processing signals for voice communication by IP telephone are used for uplink and downlink between the slave station 1 and the master station 2 provided separately from the CSC line and the communication line instead of the uplink CSC line 4 and the downlink CSC line 5. A control line (not shown in FIG. 2 but corresponding to the upstream CSC line 4 and the downstream CSC line 5) may be provided and transmitted / received via this control line, and the Invite control signal and response to the above Invite message. By transmitting and receiving signals between the slave station 2 and the master station 1 via this control line, a large amount of IP telephone connection processing occurs in the CSC line and the communication line, and the DAMA line control function is impaired, resulting in improved communication efficiency. It is possible to prevent the decrease.

It is a block diagram showing the structure of the satellite communication system which concerns on Embodiment 1 of this invention. It is a schematic diagram showing the arrangement | positioning on the frequency axis of the line to be used. It is a block diagram showing the structure of the sub_station | mobile_unit which concerns on Embodiment 1 of this invention, and a master station. It is a process sequence diagram showing the process with respect to an Invite message.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Master station 2 Slave station 3 Communication satellite 4 Uplink CSC line 5 Downlink CSC line 6 Communication line 7 Parent station satellite communication apparatus 8 Line control apparatus 9 SIP server apparatus 16 Location server 17 Proxy server 19 IP telephone 23 Satellite communication apparatus 24 Satellite GW apparatus

Claims (10)

In a line assignment type satellite communication method for requesting line assignment from a slave station by a CSC line passing through a satellite, assigning a communication line by the master station, and performing satellite communication between the slave station and the partner slave station, Based on the message from the IP telephone connected to the station, the slave station generates a control signal to be transmitted through the CSC line and transmits the control signal through the CSC line. At the master station that has received the control signal, A satellite communication method, wherein the message is reproduced. Based on the message from the connected IP phone in the slave station that requests line assignment by the CSC line via the satellite, is assigned the communication line by the master station, and performs satellite communication with the partner slave station, A child comprising: a satellite GW device that generates a control signal to be transmitted through the CSC line; and a satellite communication device that transmits the control signal generated by the satellite GW device to the master station through the CSC line. Bureau. In a slave station that requests line assignment by a CSC line via a satellite, is assigned a communication line by a master station, and performs satellite communication with a partner slave station, a terminal device group including a connected IP phone A determining means for determining from the received data that the received data is a message from the IP telephone, and when the determining means determines that the received data is a message from the IP telephone, A slave station comprising: a satellite GW apparatus having message processing means for generating a control signal to be transmitted; and a satellite communication apparatus for transmitting the control signal to the master station via the CSC line. Based on the channel allocation request transmitted from the slave station via the CSC channel via the satellite, the master station that allocates the communication channel for satellite communication performed between the slave stations receives the control signal transmitted from the slave station via the CSC channel. A master station satellite communication device, and a line control device for reproducing a message from the IP telephone connected to the slave station based on a control signal received by the master station satellite communication device. Bureau. In a line assignment type satellite communication method for requesting line assignment from a slave station by a CSC line passing through a satellite, assigning a communication line by the master station, and performing satellite communication between the slave station and the partner slave station, Based on the invite message by the SIP protocol from the IP telephone connected to the station, a first control signal to be transmitted through the CSC line is generated and transmitted through the CSC line, and the parent that has received the first control signal is received. The station searches for the IP address of the other party IP telephone that is the destination of the invite message and the slave station number of the other party slave station to which it is connected, and sends a second control signal to the other party slave station via the CSC line. Transmitting and receiving the second control signal, the partner slave station reproduces the invite message and transmits it to the partner IP phone. . In a slave station that requests line assignment by a CSC line via a satellite, is assigned a communication line by a master station, and performs satellite communication with a partner slave station, a terminal device group including a connected IP phone A discriminating means for discriminating from the received data that the received data is an invite message by the SIP protocol from the IP telephone, and when the discriminating means discriminates that the received data is an invite message by the SIP protocol, the CSC line A satellite GW device having a message processing means for generating a first control signal transmitted by a satellite communication device, and a satellite communication device for transmitting the control signal to the parent station via the CSC line. . SIP protocol originated from an IP telephone connected to the slave station in the master station that allocates a communication line for satellite communication performed between the slave stations based on a channel assignment request transmitted from the slave station via the CSC line via the satellite The master station satellite communication device that receives the first control signal generated based on the invite message by the CSC line, and the destination of the invite message based on the first control signal received by the master station satellite communication device Search means for searching for the IP address of the partner IP telephone and the slave station number of the partner slave station to which it is connected, and the above-mentioned invite message transmitted to the partner slave station via the CSC line. And a message processing means for generating a second control signal for reproducing the master signal. In the line assignment type satellite communication method for requesting line assignment from a slave station via a CSC line via a satellite, assigning a communication line by the master station, and performing satellite communication between the slave station and the partner slave station, the CSC A control line is provided separately from the line and the communication line, and based on a message from the IP phone connected to the slave station, a control signal to be transmitted by the slave line is generated by the slave station and the control line is used. A satellite communication method, wherein the message is reproduced by the master station that has transmitted and received the control signal. Based on the message from the connected IP phone in the slave station that requests line assignment by the CSC line via the satellite, is assigned the communication line by the master station, and performs satellite communication with the partner slave station, A satellite GW apparatus that generates a control signal to be transmitted through a control line provided separately from the CSC line and the communication line, and a satellite communication that transmits the control signal generated by the satellite GW apparatus to the master station through the control line A slave station characterized by comprising a device. Based on a channel allocation request transmitted from a slave station via a CSC channel passing through a satellite, a control signal transmitted from the slave station is transmitted to the CSC channel and the slave station in a master station that allocates a communication channel for satellite communication performed between the slave stations. A master station satellite communication apparatus that receives a control line provided separately from the communication line, and a line control that reproduces a message from the IP telephone connected to the slave station based on a control signal received by the master station satellite communication apparatus A master station characterized by comprising a device.

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