JP2001177556A - Group broadcast communication system in dama satellite communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform group broadcast communications in which the configurations of a broadcast group can be flexibly changed in accordance with a request from a slave station in a DAMA satellite communication system. SOLUTION: In a slave station R, a communication line controlling part 23 prepares a broadcast line setting request message on the basis of a transmission start request and transmits the message to a master station C through a common control channel frame processing part 22 and a transmitting and receiving part 21 via a satellite S. In the master station C, a communication line managing part 13 receives the broadcast line setting request message, prepares and stores a broadcast group management table and issues a frequency acquisition request. A frequency managing part 14 acquires an empty frequency band of a bandwidth necessary to communications from a frequency pool in accordance with the frequency acquisition request and allocates the frequency band to a broadcast line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a group broadcasting system in a DAMA satellite communication system, and more particularly, to a system in which any one of a plurality of slave stations transmits a communication request with another slave station using a common control channel. To the master station via satellite, and based on the communication request, the master station allocates a necessary frequency band to the communication line, and performs voice communication or data communication between the slave station requesting communication and the slave station connected to the communication. The present invention relates to a group broadcast communication system in a DAMA satellite communication system that enables the communication.

[0002]

2. Description of the Related Art As one of multiple access satellite communication systems for communicating voice or data between ground stations via satellites, a frequency division access (FDMA) that allocates a frequency band to each communication line.
Multiple Access) system. This F
Among the DMA systems, the S system is suitable for a satellite communication system composed of a large number of ground stations having a relatively small communication capacity.
CPC (Single Channel Per Car)
rier) method. In the SCPC method, one carrier signal is assigned to one voice or data communication line, and therefore, the assignment of a frequency band to a communication line is very flexible.

[0003] When classified according to the method of allocating the frequency band to the communication line, pre-assigned multiple access (PAM) is used.
A: Pre Assignment Multiple
Access) and demand assign multiple access (D
AMA: Demand Assignment Multi
(IP) system. In the PAMA method, a frequency band is fixedly assigned to a communication line.
Even when communication is not in progress, the communication line is put on hold, and the use efficiency of the communication line is poor, and the number of ground stations accommodated is limited. For this reason, a DAMA that allocates a frequency band to a communication line only when a communication request is issued.
In many cases, the system is adopted.

A satellite communication system of the DAMA system (hereinafter, referred to as "DAMA system")
DAMA satellite communication system) is generally configured as shown in FIG. This DAMA satellite communication system includes a plurality of n slave stations R1 to Rn (hereinafter, any one or all of the slave stations are indicated by R), allocation of a frequency band to a communication line, and connection of each slave station R. The master station C that manages the situation, the satellite S as a relay station, and the master station C
It is composed of an AN (Local Area Network), a monitoring control device W which is connected by a serial line or the like and performs monitoring control of the entire DAMA satellite communication system.
In the DAMA satellite communication system, there is a configuration in which the assignment of the frequency band to the communication line is controlled only by the slave station R and the master station C is not provided. Here, a configuration in which the master station C performs centralized control is shown.

[0005] When a communication request occurs, the slave station R receives a common control channel (CSC: CommonSignallin).
g Channel) to exchange connection control information. Now, assuming that a communication request to another slave station Rq has occurred in a certain slave station Rp, the slave station Rp has a line containing the address of the slave station Rq of the communication connection destination and the frequency bandwidth necessary for the communication line. A setting request message is transmitted to the master station C via the satellite S using the uplink common control channel.

In response to the line setting request message, the master station C checks whether or not the slave station Rq of the communication connection destination is in a communicable state. Assign frequency bands to communication lines,
A frequency setting request message including the allocated frequency band information is transmitted to the slave station Rp of the communication request source and the slave station Rq of the communication connection destination using the satellite S by using the downlink common control channel.
Send via Thereby, the slave station Rp of the communication request source and the slave station Rq of the communication connection destination can perform communication by the SCPC method via the satellite S using the communication line of the allocated frequency band. Thereafter, the slave stations Rp and Rq that have completed the communication each transmit a communication stop request message to the master station C via the satellite S. When receiving the communication stop request message, the master station C releases the frequency band allocated to the communication line and returns the frequency band to the frequency pool.

In an actual satellite communication system,
In order to be able to provide communication services flexibly, each slave station R switches the mode so that the DAMA method can be used for PAM.
In many cases, it can be adapted to the A method. On the other hand, as a communication mode of each of the slave stations R, there is a one-to-one communication (point-to-point communication) and a broadcast communication (broadcast communication) utilizing characteristics of satellite communication. Group broadcast communication (multicast communication), which is a communication that broadcasts only to a certain station group from
Used for broadcasting and data distribution. If this group broadcast communication is used, it is possible to divide the substation R into broadcast groups, and to operate such that a certain broadcast group performs TV broadcasting and a certain broadcast group performs program distribution.

Conventionally, however, the DAMA system can only be used for one-to-one communication between a certain slave station R and another slave station R. To perform group broadcast communication, the PAMA system must be used. As a result, the frequency band could not be used efficiently.

For this reason, in the "satellite communication system" disclosed in Japanese Patent Application Laid-Open No. 6-140968, when a broadcast request is made, the demand is determined by the broadcast group number received from the broadcast originating terminal (transmitting station). Referring to the assignment table, each receiving terminal station (receiving station) constituting the broadcast group is determined, and an empty information channel is selected, and communication is performed with the broadcast transmitting terminal station and the broadcast receiving terminal station via the common control channel. By dynamically assigning a frequency band to a line, D
Group broadcast by the AMA method has been enabled.

[0010]

However, in the above-mentioned prior art, each terminal station (receiving station) constituting a broadcast group is determined by referring to a fixed table called a demand assignment table. Therefore, there has been a problem that the network configuration for performing the group broadcast cannot be flexibly changed.

An object of the present invention is to provide a group broadcast in a DAMA satellite communication system capable of flexibly changing the configuration of a broadcast group in response to a request from a slave station. An object of the present invention is to provide a communication system.

[0012]

According to the present invention, there is provided a group broadcast communication system in a DAMA satellite communication system, wherein any one of a plurality of slave stations transmits a communication request with another slave station to a common control channel. To the master station via satellite, and based on the communication request, the master station allocates a necessary frequency band to the communication line, and performs voice communication or data communication between the slave station requesting communication and the slave station connected to the communication. In a DAMA satellite communication system enabling communication, a group broadcast communication capable of flexibly changing the configuration of a broadcast group by a satellite communication message transmitted / received between the slave station and the master station using a common control channel is provided. It is characterized in that it can be performed. Also,
The master station links, in broadcast group units, a broadcast group management table, a slave station information management table linked to the broadcast group management table as transmission station information, and a link to the broadcast group management table as reception station information. Done 1
It is characterized by holding at least one slave station information management table. Further, the satellite communication message includes a broadcast line setting request message, a broadcast line release request message, a communication start request message, a communication stop request message, a frequency setting request message, and a broadcast group registration / deletion notification message. Features.

Further, in the group broadcast communication system in the DAMA satellite communication system of the present invention, any one of a plurality of slave stations transmits a communication request with another slave station via a satellite using a common control channel. To notify the master station, and based on the communication request, the master station allocates a necessary frequency band to the communication line to enable voice communication or data communication between the communication requesting slave station and the communication connection destination slave station. In the DAMA satellite communication system, the master station is, for each broadcast group, a broadcast group management table, one slave station information management table linked to the broadcast group management table as transmission station information, and the broadcast station. A communication line management unit holding one or more slave station information management tables linked as reception station information to the group management table, and a bandwidth required for communication from the communication line management unit Acquiring a free frequency band from the frequency pool in response to the frequency acquisition request including, and notifying the frequency information of the obtained free frequency band to the communication line management unit and responding to the frequency setting release notification from the communication line management unit A frequency management unit for returning a frequency band to a frequency pool, wherein the slave station commonly controls a broadcast line setting request message and a broadcast line release request message based on a communication start request and a communication stop request received from the terrestrial interface unit. Frequency setting and frequency according to a communication start request message, a frequency setting request message and a communication stop request message transmitted to the master station via a satellite using a channel and received from the master station via the satellite using a common control channel. Releases the settings to control the broadcast line and the ground interface. The base station notifies the broadcast channel state of the broadcast line, and registers the broadcast group according to the broadcast group registration notification message and the broadcast group deletion notification message received from the master station via the satellite using the common control channel. A communication line control unit for notifying the terrestrial interface unit of deletion and deletion, voice communication or data communication with the terrestrial line, a communication start request and a communication stop request from the terrestrial line, a broadcast group registration notification and a broadcast to the terrestrial line And a ground interface unit used for notification of connection control information such as a group deletion notification. Further, the broadcast group management table includes a transmission station address, a connection status, a pointer to a transmission station information management table, a pointer to a reception station information management table, allocated frequency information, and communication parameters. Further, the slave station information management table comprises a slave station address, slave station information / status, a pointer to a broadcast group management table, and a pointer to a reception station information management table of the same broadcast group. . Furthermore, the broadcast line setting request message includes a satellite header, a broadcast line setting request, a calling station address, a communication parameter, transmission / reception designation, the number of slave stations,
And slave station addresses for the number of slave stations. Further, the broadcast channel release request message comprises a satellite header, a broadcast channel release request, a transmitting station address, the number of receiving stations to be released, and the receiving station addresses for the number of receiving stations to be released. Further, the communication start request message comprises a satellite header, a communication start request, and a source station address. Still further, the communication stop request message includes a satellite header, a communication stop request, and a source station address.
Further, the frequency setting request message includes a satellite header,
It is characterized by comprising a frequency setting request, a calling station address, assigned frequency information, and communication parameters.
Further, the broadcast group registration / deletion notification message comprises a satellite header, a broadcast group registration / deletion, a transmitting station address, a transmitting station address, and a registration / deletion type.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is a diagram showing a general configuration of a DAMA satellite communication system to which the group broadcast system according to one embodiment of the present invention is applied. As described above, this DAMA satellite communication system has a plurality of n slave stations R1 to R
n, a master station C for managing allocation of frequency bands to communication lines, line connection of each slave station R, and a satellite S as a relay station.
And a supervisory control device W for performing supervisory control of the entire DAMA satellite communication system. The slave station R makes a line setting request using a common control channel, and the master station C sends a frequency band to the communication line. , And the slave stations R communicate with each other.

Referring to FIG. 1, the master station C includes a common control channel transmitting / receiving section 11, a common control channel frame processing section 12, a communication line management section 13, and a frequency management section 14. .

The common control channel transmission / reception section 11 and the common control channel frame processing section 12 are well known to those skilled in the art and are not directly related to the present invention, so that detailed description thereof will be omitted.

The communication line management unit 13 stores a broadcast group management table 15 as shown in FIG.
And one slave station information management table 16 linked to the broadcast group management table 15 as transmission station information, and one or more slave station information management tables 16 linked to the broadcast group management table 15 as reception station information And hold.

Referring to FIG. 4, a broadcast group management table 15 includes a transmission station address, a connection status, a pointer to a transmission station information management table, a pointer to a reception station information management table, and assigned frequency information (for example, center frequency). , Bandwidth) and communication parameters (parameters for determining frequency bandwidth, transmission power, etc.).

Referring to FIG. 5, the slave station information management table 16 includes a slave station address, slave station information / status, a pointer to a broadcast group management table, and a pointer to a reception station information management table of the same broadcast group. Consists of

The frequency management unit 14 includes the communication line management unit 13
A free frequency band is obtained from the frequency pool in response to a frequency obtaining request including a bandwidth required for communication from the communication line, and frequency information of the obtained free frequency band is notified to the communication line management unit 13. Further, the frequency management unit 14 is a communication line management unit 1.
The corresponding frequency band is returned to the frequency pool in response to the frequency setting release notification from # 3.

As shown in FIG. 12, the method by which the frequency management unit 14 allocates a frequency band is determined by searching for a free frequency band equal to or larger than the bandwidth required by the communication line from the head of the frequency pool. General.

Referring to FIG. 1, the slave station R includes a transmitting / receiving unit 2
1, a common control channel frame processing unit 22, a communication line control unit 23, a terrestrial interface unit 24, and a frame processing unit 25.

The transmission / reception unit 21, the common control channel frame processing unit 22 and the frame processing unit 25 are well known to those skilled in the art and are not directly related to the present invention, so that detailed description thereof will be omitted.

The communication line control unit 23 commonly controls a broadcast line setting request message or a broadcast line release request message based on a transmission start request, a reception start request, a transmission stop request, or a reception stop request received from the ground interface unit 24. The data is transmitted to the master station C via the satellite S using the common control channel via the channel frame processing unit 22 and the transmission / reception unit 21. The communication line control unit 23 responds to the broadcast line setting request message and the broadcast line release request message from the master station C via the satellite S using the common control channel, the communication start request message, and the frequency setting request message. According to the message and the communication stop request message, the frequency setting and the frequency setting release are performed in the frame processing unit 25 to control the broadcast line. Further, the communication line control unit 23 notifies the terrestrial interface unit 24 of the line status of the broadcast line, and when there is a broadcast group registration notification message and a broadcast group deletion notification message from the master station C, To the ground interface unit 24.

The ground interface unit 24 controls connection such as voice communication or data communication with the ground line, a communication start request and a communication stop request from the ground line, a broadcast group registration notification and a broadcast group deletion notification to the ground line. Used for notification of information. The terrestrial interface unit 24 corresponds to a terrestrial line communication protocol. If the terrestrial line communication protocol is different, the terrestrial interface unit 24 will be different. The output interface is the same.

Referring to FIG. 6, a satellite communication message generally includes a satellite header, a message type, a source station address (address of a child station of a message source), and additional information. The satellite header is for controlling communication of the message.

The broadcast line setting request message is a satellite communication message transmitted from the slave station R to the master station C, and includes a satellite header, a broadcast line setting request, a calling station address, a communication parameter, a transmission / reception designation, It consists of the number of stations and the slave station addresses for the number of slave stations. If the send / receive specification is send,
The subsequent slave station number indicates the number of receiving stations, and the slave station address indicates the receiving station address. If you do not specify a receiving station,
The number of receiving stations is 0 and there is no slave station address. When the transmission / reception designation is reception, the number of slave stations is fixed at 1, and the slave station address indicates a transmission station address of a participating broadcast group.

The broadcast line release request message is a satellite communication message transmitted from the slave station R to the master station C, and includes a satellite header, a broadcast line release request, an originating station address,
It consists of the number of receiving stations to be released and the receiving station addresses for the number of receiving stations to be released. In the case of a broadcast line release request message from a broadcast group transmitting station, there may be cases where there is a release target receiving station or there may be no broadcast line release request message, but in the case of a broadcast line release request message from a broadcast group reception station Since the receiving station to be released is the own station, the number of receiving stations is 0 and the receiving station address is not specified.

Further, the communication start request message is a satellite communication message transmitted from the master station C to the slave station R,
Satellite header, communication start request, and source station address (=
Transmission station address). Hereinafter, a communication start request message requesting start of transmission is referred to as a transmission start request message, and a message requesting start of reception is referred to as a reception start request message. The transmission start request message is
May include receiving station addresses. The reception start request message includes the address of the transmitting station of the participating broadcast group.

Further, the communication stop request message is:
This is a satellite communication message transmitted from the master station C to the slave station R, and includes a satellite header, a communication stop request, and a calling station address (= transmitting station address). Hereinafter, a communication stop request message requesting a stop of transmission is referred to as a transmission stop request message, and a communication stop request message requesting a stop of reception is referred to as a reception stop request message.

The frequency setting request message is a satellite communication message transmitted from the master station C to the slave station R,
It consists of a satellite header, frequency setting request, transmitting station address, assigned frequency information, and communication parameters.

The broadcast group registration / deletion notification message is a satellite communication message transmitted from the master station C to the slave station R, and includes a satellite header, broadcast group registration / deletion,
It consists of a sending station address, a sending station address, and a registration / deletion type. Hereinafter, a broadcast group registration / deletion notification message whose registration / deletion type is registered is referred to as a broadcast group registration notification message.
The deletion notification message is called a broadcast group deletion notification message.

Referring to FIG. 7, the processing at the time of receiving the broadcast line setting request message in the communication line management unit 13 of the master station C includes a message receiving step 101, a message type judging step 102, and a slave station information management table acquisition. Step 103 and transmission / reception designation determination step 104
And broadcast group management table link determination step 10
5, a broadcast group management table creation / slave station information management table link step 106, a frequency bandwidth determination / acquisition step 107, and a receiving station designation determination step 108
A slave station information management table acquisition / consistency check step 109; a slave station information management table link / communication start request transmission step 110; a broadcast group management table acquisition / slave station information management table link step 111; Sending frequency setting request message to
, A frequency setting request message transmitting step 113 to the transmitting station, and a broadcast group registration notification message transmitting step 114.

Referring to FIG. 8, the processing at the time of receiving the broadcast line release request message in the communication line management unit 13 of the master station C includes a message type determination step 201, a message discard step 202, and a slave station information management table acquisition. Step 203, a broadcast group management table specifying step 204, a transmitting station address determining step 205, and a communication stop request message transmitting step 206 to the transmitting station.
Step 207 of determining the number of receiving stations to be released, Step 208 of transmitting a communication stop request message to the receiving stations, Step 209 of transmitting a communication stop request message to the transmitting station and all receiving stations, and Step of transmitting a broadcast group deletion notification message 210.

Referring to FIG. 9, the processing at the time of receiving a request in the communication line managing section 23 of the slave station R includes a request receiving step 301, a transmission start request determining step 302, a broadcast line setting request message creating / transmitting step. 303, a reception start request determination step 304, a broadcast line setting request message creation / transmission step 305, a communication stop request determination step 306, a broadcast line release request message creation / transmission step 307, and a request discard step 308. Consists of

Referring to FIG. 10, the processing at the time of receiving a message in the communication line management unit 23 of the slave station R includes a message receiving step 401, a frequency setting request message determining step 402, and a frequency setting /
Line state notification step 403, communication start request message determination step 404, and reception start possibility determination step 4
05, a message discarding step 406, a broadcast line release request message transmitting step 407, a communication stop request message determining step 408, a frequency setting release / line state notification step 409 to the frame processing unit, a broadcast group registration / Deletion notification message determination step 410
And a broadcast group registration / broadcast group deletion notification step 411 and a message discarding step 412.

FIG. 11 shows distribution devices E1 and E to slave stations R1 and R2 in order to distribute data such as images and files using the DAMA satellite communication system shown in FIG.
2 (hereinafter, any one or all of the distribution apparatuses are indicated by E), and the receiving stations T3 to Rn are connected to the receiving terminals T3 to Rn.
1 shows a group broadcast system to which Tn-2 (hereinafter, any one or all of the receiving terminals are indicated by T) are connected. The configuration of the group broadcast communication system is such that the distribution device E such as E1 can request the setting / cancellation of the broadcast line by designating the receiving station address by itself, and control the data transmission to the specific receiving terminal T. In addition to being used for purposes such as file distribution, a distribution device E such as E2 performs only a data transmission procedure, and a receiving terminal T selects and receives data from data being transmitted by a plurality of distribution devices E. It can also be used for purposes such as broadcasting.

Next, the operation of the group broadcast communication system in the DAMA satellite communication system according to the present embodiment configured as described above will be described with reference to the group broadcast communication system shown in FIG. A description will be given along the flow of No. 15.

(1) Broadcast line setting from the transmitting station FIG. 13 shows that the distribution device E1 has the receiving terminals T1, T2 and T
3 shows a flow when a transmission start request to which the addresses of slave stations R3, R4, and R5 serving as receiving stations are added is sent to the slave station R1 in order to perform file distribution.

In the slave station R1, when the communication line control unit 23 receives a transmission start request from the distribution device E1 via the ground interface unit 24 (step 301), it is a transmission start request (No in step 302). , The transmitting station address (= transmitting station address) based on the transmission start request
1. Send a transmission / reception designation, create a broadcast channel setting request message with the number of slave stations as 3, and the addresses of the slave stations as R3, R4 and R5, and send them through the common control channel frame processing unit 22 and the transmission / reception unit The data is transmitted to the master station C via the satellite S (step 303).

In the master station C, the communication line manager 13 sends the broadcast line setting request message from the slave station R1 to the transmitter / receiver 11.
When the message is received via the common control channel frame processing unit 12 (step 101), the message type is a broadcast channel setting request (step 102). The slave station information management table 16 to be used as the station address is obtained (step 103).

Next, the communication line manager 13 determines whether the transmission / reception designation in the broadcast line setting request message is transmission or reception (step 104). It is determined whether the broadcast group management table 15 is linked to the slave station information management table 16 and whether the slave station information management table is linked to the transmission station link of the broadcast group management table (step 105).

Since the broadcast group having the slave station R1 as the transmitting station is not registered and the broadcast group management table 15 is not linked to the slave station information management table 16 of the slave station R1, the communication line management is performed. The unit 13 transmits the broadcast group management table 1 using the address of the slave station R1 as the transmission station address.
5 is created, and the slave station information management table 16 of the slave station R1 is linked to the created broadcast group management table 15 as transmission station information (step 106).

Next, the communication line manager 13 determines the necessary frequency bandwidth based on the communication parameters in the broadcast line setting request message, issues a frequency acquisition request to the frequency manager 14 and A free frequency band corresponding to a small bandwidth is obtained, and the obtained free frequency band is written to the broadcast group management table 15 as allocated frequency information (step 107).

Upon receiving the frequency acquisition request, the frequency management unit 14 acquires a free frequency band corresponding to the bandwidth from the frequency pool, and notifies the communication line management unit 13 of the position information (center frequency) of the acquired frequency band. .

Subsequently, the communication line management unit 13 determines whether or not a receiving station is specified based on the number of slave stations in the broadcast line setting request message (step 108).

Since the number of slave stations is 3 and the receiving station is designated, the communication line manager 13 has the slave station addresses R3, R4 and R5 in the broadcast line setting request message as slave station addresses. It acquires two slave station information management tables 16 and checks the consistency of slave station information and status (step 109).

If there is no problem in the consistency check, the communication line management unit 13 stores the slave station information management tables 16 of the slave stations R3, R4 and R5 serving as the receiver stations in the broadcast group management table 15 as the receiver station information. And transmits a transmission start request message to the slave stations R3, R4, and R5 serving as receiving stations via the satellite S via the common control channel frame processing unit 12 and the common control channel transmitting / receiving unit 11 (step 110). .

In each of the slave stations R3, R4 and R5, the communication line control unit 23 transmits a transmission start request message to the transmission / reception unit 2.
1 and received via the common control channel frame processing unit 22 (step 401), since the message type is a transmission start request (step 404: yes), if the reception can be started (step 405: yes), nothing Without discarding the transmission start request message (step 40).
6). If reception cannot be started (NO in step 405), the communication line control unit 23 sets the number of receiving stations to be canceled to 1,
A broadcast channel release request message having the receiving station address as its own station address is transmitted to the master station C via the common control channel frame processing section 12 and the common control channel transmitting / receiving section 11 (step 407).

In the master station C, the communication line management unit 13
Sends a frequency setting request message including allocated frequency information and communication parameters to slave stations R3, R4 and R5 serving as receiving stations.
2 and the satellite S via the common control channel transceiver 11
The data is transmitted via the Internet (step 112).

In each of the slave stations R3, R4 and R5, when the communication line control unit 23 receives the frequency setting request message via the transmitting / receiving unit 21 and the common control channel frame processing unit 22 (step 401), the message type is Since it is a setting request (step 402), frequency information and communication parameters are extracted from the frequency setting request message, the frequency is set in the frame processing unit 25, and a line is established in the terrestrial interface unit 24 (frequency to the communication line). A line status notification is sent to inform the user of the allocation of the band (step 403). Note that the line status notification at the receiving station also includes the transmitting station address.

Upon receiving the line state notification, the terrestrial interface unit 24 notifies the receiving terminals T1 and T1 that the line state has been established.
Notify T2 and T3.

In the master station C, the communication line manager 13
Transmits a frequency setting request message including allocated frequency information and communication parameters to the slave station R1 as a transmitting station via the satellite S via the common control channel frame processing unit 12 and the common control channel transmitting / receiving unit 11 (step 113).

In the slave station R1, when the communication line control unit 23 receives the frequency setting request message via the transmitting / receiving unit 21 and the common control channel frame processing unit 22 (step 401), the message type is the frequency setting request. (Yes in step 402), the assigned frequency information and communication parameters are extracted from the frequency setting request message, the frequency is set in the frame processing unit 25, and the line is established (assignment of the frequency band to the communication line) to the ground interface unit 24. A notification of the line status is sent (step 403).

When receiving the line state notification, the terrestrial interface unit 24 notifies the distribution device E1 that the line state has been established.

In the master station C, the communication line manager 13
However, in order to notify that a broadcast group having the slave station R1 as a transmitting station has been registered, a broadcast group registration notification message including the slave station address R1 as the transmitting station address is shared by all subordinate slave stations R1 to Rn. The transmission is performed via the satellite S via the control channel frame processing unit 12 and the common control channel transmission / reception unit 11 (step 114).

In each of the slave stations R1 to Rn, the communication line control unit 2
3 transmits a broadcast group registration notification message to the transmitting / receiving unit 21
When it is received via the common control channel frame processing unit 22 (step 401), the message type is a broadcast group registration notification (step 410: No).
A broadcast group registration notification is sent to the ground interface unit 24 based on the broadcast group registration notification message (step 411).

When receiving the broadcast group registration notification, the terrestrial interface unit 24 notifies the distribution apparatuses E1 and E2 and the receiving terminals T1 to Tn-2 that the broadcast group has been registered.

If the receiving station address is not specified in the transmission start request from the distribution apparatus E, the processing for the receiving station in the above procedure is not performed. There is no state.

(2) Broadcasting Line Setting from Receiving Station FIG. 14 shows a procedure for a broadcast group in which the child station R2 is registered as a transmitting station and already exists, in the same manner as the procedure shown in (1). Shows the flow when the receiving terminal T4 joins the broadcast group of the distribution device E2.

Since the receiving terminal T4 already knows from the broadcast group registration notification from the local station R6 that there is a broadcast group with the local station R2 as the transmitting station, the receiving terminal T4 sets the broadcast group to this broadcast group. When participating in
Then, a reception start request designating the address No. 2 is transmitted to the slave station R6.

In the slave station R6, when the communication line control unit 23 receives the reception start request via the terrestrial interface unit 24 (step 301), it is a reception start request (step 304). Based on the originating station address R6, send / receive designation is received, the number of slave stations is 1,
A broadcast channel setting request message with the slave station address set to R2 is created and transmitted to the master station C via the satellite S via the common control channel frame processing section 22 and the transmission / reception section 21 (step 305).

In the master station C, the communication line manager 13 sends a broadcast line setting request message from the slave station R6 to the transmitter / receiver 11.
When the message is received via the common control channel frame processing unit 12 (step 101), the message type is a broadcast channel setting request (step 102). The slave station information management table 16 to be used as the station address is obtained (step 103).

Next, since the transmission / reception designation in the broadcast channel setting request message is "reception" (received in step 104), the communication line management unit 13 sets the broadcast group having the slave station address R2 as the transmission station address. Obtains the management table 15 and stores the slave station R in the obtained broadcast group management table 15.
6 is linked as the receiving station information (step 111).

Subsequently, the communication line management unit 13 transmits the transmission station address R2, the frequency setting request message including the allocated frequency information and the communication parameter to the slave station R6 serving as the receiving station, and transmits and receives the message to and from the common control channel frame processing unit 12 The data is transmitted via the satellite S via the unit 11 (step 112).

In the slave station R6, when the communication line control section 23 receives the frequency setting request message via the transmitting / receiving section 21 and the common control channel frame processing section 22 (step 401), the message type is the frequency setting request. (Step 402), the assigned frequency information and the communication parameters are extracted from the frequency setting request message, the frequency is set in the frame processing unit 25, and the line establishment (allocation of the frequency band to the communication line) is notified by the line state notification. The interface unit 24 is notified (step 403).

When receiving the line state notification, the terrestrial interface unit 24 notifies the receiving terminal T4 that the line state has been established.

In the master station C, the communication line manager 13
Refers to the connection status in the broadcast group management table 15, if the connection state, that is, if the slave station R 2 serving as the transmission station is not in the transmission state, a frequency setting request message including frequency information and communication parameters assigned to the slave station R 2. Is transmitted via the common control channel frame processing unit 12 and the common control channel transmission / reception unit 11 via the satellite S, and the connection status is set to the connection state (step 113).

In the slave station R2, when the communication line control section 23 receives the frequency setting request message via the transmitting / receiving section 21 and the common control channel frame processing section 22 (step 401), the message type is the frequency setting request. (Yes in step 402), the assigned frequency information and communication parameters are extracted from the frequency setting request message, the frequency is set in the frame processing unit 25, and the line is established (assignment of the frequency band to the communication line) to the ground interface unit 24. A notification of the line status is sent (step 403).

In the master station C, the communication line manager 13
Transmits a broadcast group registration notification message including a slave station address R2 as a transmission station address to all subordinate slave stations R1 to Rn in order to notify that a broadcast group having the slave station R2 as a transmission station has been updated and registered. Transmission is performed via the satellite S via the common control channel frame processing unit 12 and the common control channel transmission / reception unit 11 (step 114).

In each of the slave stations R1 to Rn, the communication line control unit 2
3 transmits a broadcast group registration notification message to the transmitting / receiving unit 21
When it is received via the common control channel frame processing unit 22 (step 401), the message type is a broadcast group registration notification (step 410: No).
A broadcast group registration notification is sent to the ground interface unit 24 based on the broadcast group registration notification message (step 411).

When receiving the broadcast group registration notification, the terrestrial interface unit 24 notifies the distribution apparatuses E1 and E2 and the receiving terminals T1 to Tn-2 that the broadcast group has been registered.

(3) Release of Broadcasting Line from Transmitting Station FIG. 15 shows a broadcast group in which the slave station R1 created in FIG. 13 is used as a transmitting station.
And a flow when the distribution to T3 is stopped.

The distribution device E1 transmits a transmission stop request designating the slave station addresses R4 and R5 as the receiving station addresses.

In the slave station R1, when the communication line control unit 23 receives a transmission stop request from the distribution device E1 via the ground interface unit 24 (step 301), it is a communication stop request (No in step 306). Based on the transmission stop request, a broadcast line release request message is created with the number of receiving stations to be released set to 2 and the receiving station addresses R4 and R5, and transmitted to the satellite S via the common control channel frame processing unit 22 and the transmitting / receiving unit 21. The data is transmitted to the master station C via the terminal (step 307).

In master station C, when communication line manager 13 receives a broadcast line release request message via transmission / reception unit 11 and common control channel frame processor 12 (step 101), the message type is broadcast line release. Since the request is a request (No in Step 102, No in Step 201), the slave station information management table 1 having the calling station address R1 in the broadcast channel release request message as the slave station address.
6 (step 203), and specifies the broadcast group management table 15 from the pointer to the broadcast group management table in the slave station information management table 16 (step 20).
4).

Next, the communication line management unit 13 determines whether or not the source station address R1 in the broadcast channel release request message matches the transmission station address R1 in the broadcast group management table 15 (step 205). , Matches
Further, it is determined whether or not the number of receiving stations to be released in the broadcast line release request message is set (step 20).
7). Now, since the number of receiving stations to be released is set to 2, the communication line management unit 13 follows the link from the pointer to the receiving station information management table in the broadcast group management table 15 and receives the receiving station addresses R4 and R5. Are specified as slave station addresses, and a communication stop request message with the source station address (= transmitting station address) as R1 is sent to the common control channel frame processing section 12 and the common control channel transmitting / receiving section 11. To the slave stations R4 and R5 via the satellite S, and removes the slave station information management table 16 of the slave stations R4 and R5 from the link of the broadcast group management table 15 having the sending station address of R1 (step 208). .

In each of the slave stations R4 and R5, when the communication line control unit 23 receives the broadcast group deletion notification message via the transmission / reception unit 21 and the common control channel frame processing unit 22 (step 401), the message types are the same. Since it is a broadcast group deletion notification (step 410), the broadcast group deletion notification is notified to the ground interface unit 24 based on the broadcast group deletion notification message (step 411).

When receiving the line status notification, the terrestrial interface unit 24 notifies the receiving terminals T2 and T3 of the deletion from the broadcast group.

When the broadcast station release request message is transmitted from the transmitting station R1 without specifying the receiving station, this means that the broadcast group itself is deleted. A broadcast group deletion notification message is transmitted to the subordinate receiving station R.

More specifically, if the number of receiving stations to be released has not been set in step 207, the communication line management unit 13
Transmitting a communication stop request message to the transmitting station and the slave station R of the slave station address of all the slave station information management tables 16 linked to the broadcast group management table 15;
The link between each slave station information management table 16 and the synchronization group management table 15 is initialized (step 209).

Next, the communication line management unit 13 sets the transmitting station address to R1, the transmitting station address to R1, and the registration / deletion type to be deleted for all the slave stations R3, R4 and R5 in the broadcast group. The notification group deletion notification message is transmitted via the common control channel frame processing unit 12 and the transmission / reception unit 11 via the satellite S (step 210).

In each of the slave stations R3, R4 and R5, the communication line control unit 23 transmits the broadcast group deletion notification message to the transmission / reception unit 21 and the common control channel frame processing unit 22.
(Step 401), the broadcast group deletion notification message is transmitted to the ground interface unit 24 from the broadcast group deletion notification message (step 410).
11).

When receiving the line status notification, the terrestrial interface unit 24 notifies the receiving terminals T1, T2 and T3 of the deletion from the broadcast group.

When the master station C receives a broadcast line release request message from all the slave stations R of the corresponding broadcast group,
The corresponding broadcast group management table 15 is deleted, and a broadcast group deletion notification message is transmitted to all the slave stations R of the broadcast group via the common control channel.

(4) Release of Broadcasting Channel from Receiving Station FIG. 16 shows a broadcast group in which the receiving station T4 shown in FIG.
4 shows a flow when the reception is stopped.

Since the receiving terminal T4 already knows from the broadcast group registration notification from the local station R6 that there is a broadcast group with the local station R2 as the transmitting station, the receiving terminal T4 transmits the broadcast group to this broadcast group. If you want to be removed from
The reception stop request specifying the address of the slave station R2 is sent to the slave station R6.
Send to

In the slave station R6, when the communication line control unit 23 receives the reception stop request via the ground interface unit 24 (step 301), it is a communication stop request (step 306). A broadcast channel release request message is generated based on the number of receiving stations to be released and the address of the receiving station is R6, and is transmitted to the master station C via the satellite S via the common control channel frame processing section 22 and the transmission / reception section 21 based on the received information. (Step 307).

In master station C, when communication line manager 13 receives a broadcast line release request message via transmission / reception unit 11 and common control channel frame processor 12 (step 101), the message type is broadcast line release. Since it is a request (No in Step 102, No in Step 201), the slave station information management table 16 having the calling station address R6 as a slave station address is acquired (Step 203).
The broadcast group management table 15 is specified from the pointer to the broadcast group management table in the slave station information management table 16 (step 204).

Next, the communication line management unit 13 determines whether or not the source station address R6 in the broadcast channel release request message matches the transmission station address R2 in the broadcast group management table 15 (step 205). Since the receiving station does not match, a communication stop request message with the source station address set to R2 is transmitted to the slave station R6 via the common control channel frame processing unit 12 and the common control channel transmitting / receiving unit 11 via the satellite S, The slave station information management table 16 of the slave station R6 is disconnected from the link of the broadcast group management table 15 having the transmission station address R2 (step 206).

In the slave station R6, when the communication line control unit 23 receives the communication stop request message via the transmission / reception unit 21 and the common control channel frame processing unit 22 (step 401), the message type is a communication stop request. (No in step 408), the frame processing unit 25 is notified of the release of the frequency setting, and the terrestrial interface unit 24 is notified of the line state notification of the line release (step 40).
9).

Upon receiving the line state notification indicating that the line has been released, the ground interface unit 24 notifies the receiving terminal T4 that the line has been released.

As described above, the DAMA according to the present embodiment is
In the configuration of the group broadcast communication system in the satellite communication system, the frequency band can be efficiently used by allocating the frequency band to the communication line according to the broadcast line setting request message and the broadcast line release request message.
A group broadcast service capable of flexibly changing the network configuration according to the application while utilizing the advantages of the AMA satellite communication system is possible.

As another embodiment of the present invention, the basic configuration is as described above, but a method of notifying registration information and deletion information of a broadcast group is notified from a transmitting station using a common control channel. There is also a way to do it. In this case,
The terrestrial interface unit 24 of the slave station R has a function of transmitting a registration notification and a deletion notification of a broadcast group to the common control channel by broadcasting when transmitting a line status notification to the terrestrial line when the own station is the transmitting station. I just need. The broadcast data transmitted from the slave station R is transmitted by the common control channel frame processing unit 12 of the master station C to all the slave stations R1 to Rn under the return control. With such a configuration, when additional information such as an identification number of the content of information is added to the broadcast notification, even if the information amount is changed, it is only necessary to change the ground interface unit 24 of the slave stations R1 to Rn. Good effect can be obtained.

[0096]

As described above, according to the present invention,
The following effects are obtained.

The first effect is that the same satellite communication network can be used for various applications because the station configuration using the broadcast line can be easily and flexibly changed from each slave station.

The second effect is that the frequency band is allocated to the broadcast line according to the request as in the case of the ordinary point-to-point communication line, so that the frequency resources can be used efficiently.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a master station and a slave station to which a group broadcast communication system is applied in a DAMA satellite communication system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a general configuration of a DAMA satellite communication system.

FIG. 3 is a diagram showing a link between a broadcast group management table and a slave station information management table included in a communication line management unit in FIG. 1;

FIG. 4 is a diagram showing contents of a broadcast group management table in FIG. 3;

FIG. 5 is a diagram showing the contents of a slave station information management table in FIG. 3;

FIG. 6 is a diagram showing a format of a satellite communication message transmitted and received between a master station and a slave station in FIG. 1;

FIG. 7 is a flowchart showing processing at the time of receiving a broadcast line setting request message in the communication line management unit of the master station in FIG. 1;

FIG. 8 is a flowchart showing a process at the time of receiving a broadcast line release request message in the communication line management unit of the master station in FIG. 1;

FIG. 9 is a flowchart showing a process at the time of receiving a request from the ground in the communication line management unit of the slave station in FIG. 1;

FIG. 10 is a flowchart showing a process at the time of receiving a message from the master station in the communication line manager of the slave station in FIG. 1;

11 is a diagram illustrating an example of a group broadcast communication system in which a distribution device and a receiving terminal are connected to a slave station in the configuration of the DAMA satellite communication system illustrated in FIG. 2;

FIG. 12 is a diagram illustrating a method of acquiring a frequency pool in a frequency management unit in FIG. 1;

FIG. 13 is a flowchart showing a broadcast channel setting from a transmitting station in the group broadcast system of FIG. 11;

FIG. 14 is a flowchart showing the setting of a broadcast line from a receiving station in the group broadcast communication system of FIG. 11;

FIG. 15 is a flowchart showing release of a broadcast channel from a transmitting station in the group broadcast communication system of FIG. 11;

FIG. 16 is a flowchart showing release of a broadcast line from a receiving station in the group broadcast communication system of FIG. 11;

[Explanation of symbols]

 Reference Signs List 11 common control channel transmission / reception unit 12 common control channel frame processing unit 13 communication line management unit 14 frequency management unit 21 transmission / reception unit 22 common control channel frame processing unit 23 communication line control unit 24 ground interface unit 25 frame processing unit C master station E1, E2 distribution device R1 to Rn slave station S satellite T1 to Tn-2 receiving terminal W monitoring and control device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K030 HB11 HC10 JL02 KA05 LA17 LC09 LD06 5K033 AA01 AA03 BA13 CA17 CB13 DA01 DA05 DA18 DB12 EC03 5K072 AA14 BB12 BB15 BB22 CC05 CC15 CC25 CC32 DD01 EE05 FF03 GG04 GG03 GG03 GG03 GG03 GG03 GG03 GG03 GG04 GG03 GG03 GG03 GG03 GG03 GG03

Claims (12)

[Claims] An arbitrary one of a plurality of slave stations notifies a master station of a communication request with another slave station via a satellite using a common control channel. In a DAMA satellite communication system that enables voice communication or data communication between a communication requesting slave station and a communication connection destination slave station by allocating a necessary frequency band to a communication line, the slave station and the master station A group broadcast system in a DAMA satellite communication system, wherein a group broadcast system capable of flexibly changing the structure of a broadcast group can be performed by satellite communication messages transmitted and received between the groups using a common control channel. . 2. The broadcast receiving apparatus according to claim 1, wherein the master station includes a broadcast group management table, a slave station information management table linked to the broadcast group management table as transmission station information, and a broadcast group management table. 2. The group broadcast communication system in a DAMA satellite communication system according to claim 1, wherein one or more slave station information management tables linked as receiving station information are held. 3. The satellite communication message includes a broadcast line setting request message, a broadcast line release request message, a communication start request message, a communication stop request message, a frequency setting request message, and a broadcast group registration / deletion notification message. The group broadcast system in the DAMA satellite communication system according to claim 1, which comprises: 4. An arbitrary one of a plurality of slave stations notifies a master station via a satellite of a request for communication with another slave station using a common control channel. In a DAMA satellite communication system in which a necessary frequency band is allocated to a communication line to enable voice communication or data communication between a communication requesting slave station and a communication connection destination slave station, the master station may include a broadcast group. The unit is a broadcast group management table,
A communication line for holding a slave station information management table linked to the broadcast group management table as transmission station information, and one or more slave station information management tables linked to the broadcast group management table as reception station information Management department,
Acquiring an empty frequency band from a frequency pool in response to a frequency acquisition request including a bandwidth required for communication from the communication line management unit, and notifying the communication line management unit of frequency information of the acquired empty frequency band, A frequency management unit that returns the corresponding frequency band to the frequency pool in response to the frequency setting release notification from the communication line management unit,
A broadcast line setting request message and a broadcast line release request message are transmitted to the master station via satellite using a common control channel based on a communication start request and a communication stop request received from the terrestrial interface unit. According to the communication start request message, the frequency setting request message, and the communication stop request message received via the satellite using the control channel, frequency setting and frequency setting are canceled to control the broadcast line and to the ground interface unit. A broadcast line status is notified, and registration and deletion of the broadcast group are performed according to the broadcast group registration notification message and the broadcast group deletion notification message received from the master station via the satellite using a common control channel. A communication line controller that notifies the interface Voice communication with the line or data communication, the communication start request and the communication stop request from the landline,
A group broadcast communication system in a DAMA satellite communication system, comprising: a terrestrial interface used for notification of connection control information such as a broadcast group registration notification and a broadcast group deletion notification to a terrestrial line. 5. The broadcast group management table comprises a transmission station address, a connection status, a pointer to a transmission station information management table, a pointer to a reception station information management table, allocated frequency information, and communication parameters. Or a group broadcast communication system in the DAMA satellite communication system according to 4. 6. The slave station information management table comprises a slave station address, slave station information / status, a pointer to a broadcast group management table, and a pointer to a reception station information management table of the same broadcast group. 5. A group broadcast communication system in the DAMA satellite communication system according to 2 or 4. 7. The broadcast line setting request message comprises a satellite header, a broadcast line setting request, a calling station address, communication parameters, transmission / reception designation, the number of slave stations, and slave station addresses for the number of slave stations. A group broadcast communication system in the DAMA satellite communication system according to claim 3 or 4. 8. The broadcast channel release request message comprises a satellite header, a broadcast channel release request, a source station address, the number of receiving stations to be released, and the receiving station addresses for the number of receiving stations to be released. 4. A group broadcast communication system in the DAMA satellite communication system according to 4. 9. A group broadcast communication system in a DAMA satellite communication system according to claim 3, wherein said communication start request message comprises a satellite header, a communication start request, and a source station address. 10. The group broadcast system in a DAMA satellite communication system according to claim 3, wherein said communication stop request message comprises a satellite header, a communication stop request, and a source station address. 11. A group broadcast communication system in a DAMA satellite communication system according to claim 3, wherein said frequency setting request message comprises a satellite header, a frequency setting request, a transmitting station address, assigned frequency information, and communication parameters. 12. The DAMA satellite communication according to claim 3, wherein said broadcast group registration / deletion notification message comprises a satellite header, broadcast group registration / deletion, originating station address, transmitting station address, and registration / deletion type. Group broadcast method in the system.