JP3195610B2 - Satellite communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a communication network using a satellite line for a subscriber line or both a subscriber line and a trunk line.

[0002]

2. Description of the Related Art FIG . 4 is a block diagram showing a conventional satellite communication system in which a satellite line can be used for both a subscriber line and a trunk line . FIG. 4 shows an example of a connection sequence.

[0003] A subscriber information line for transmitting and receiving terminal information and a subscriber signal line for transmitting and receiving a call control signal are set between the terminal and the exchange. A relay line through which terminal information is transmitted and received is set up between exchanges. A terminal station is connected to some terminals and the exchange accommodating the terminals, and a satellite information terminal is used as a subscriber information line. Lines can be used.

[0004] More specifically, referring to the examples of FIGS.
1 and 52 are connected, and the terminal 41 is connected to the exchange 31 by a subscriber information line 101 and a subscriber signal line 111 by a satellite line. The terminal station 42 is connected to the exchange 31 via a subscriber information line 81 and a subscriber signal line 91 which are terrestrial lines. The terminal 43 is connected to the satellite terminal devices 56, 5
5 is connected to the exchange 33 via the subscriber information line 105 and the subscriber signal line 112 of the satellite line. The terminal station 44 is connected to the exchange 33 via a subscriber information line 82 and a subscriber signal line 92 which are terrestrial lines.

[0005] The exchanges 31 and 33 manage the attributes of the connected terminals, respectively, and are provided with terminals accommodating satellite lines, for example, the terminal 41 in the exchange 31 and the terminal 4 in the exchange 33.
Every time 3 communicates, it executes a satellite line setting request process.

The processing of setting and releasing the satellite line and the management of the satellite line are performed intensively by the satellite line controller 20. The satellite line control device 20 is connected via the line control lines 61 to 63 to the exchanges 31 and 33 to which the satellite terminal device is connected and the exchange 32 for executing the connection process of the relay section by the satellite line. The satellite terminal devices 51 to 56 are connected by satellite line control lines 71 to 74.

In this satellite communication system, when a terminal 41 accommodated in a satellite line originates a call or receives a call to the terminal 41, a subscriber information line 101 by a satellite line is set between the satellite terminal devices 51 and 52. Thus, transmission and reception of terminal information are performed. In the case of the terminal 43, a subscriber information line 105 using a satellite line is similarly used. Therefore,
When the terminal 41 and the terminal 43, which are satellite line accommodation terminals, communicate with each other, the subscriber information line
Transmission and reception of terminal information are performed via the terminals 1 and 105.

[0008]

As described above, in the conventional satellite communication system, since the exchange does not have information other than the line section for which the connection is controlled by itself, the satellite line accommodating terminals need to communicate with each other when the satellite line accommodating terminals communicate. It will go through the line at least twice. In addition, when a satellite communication terminal and a terrestrial communication terminal communicate with each other via a relay line using a satellite communication line like the satellite communication line 104 shown in FIG.
Times, at least 3 if satellite line accommodating terminals communicate
Times, via a satellite line. If the signal passes through the satellite line a plurality of times, the propagation delay time of the signal in the communication line between the terminals becomes long, and there is a disadvantage that the communication quality such as the communication quality by voice and the information transmission efficiency in data communication is deteriorated. Further, since a satellite line is set for a plurality of sections for one call, there is a disadvantage that the utilization efficiency of the satellite line is reduced.

An object of the present invention is to solve such a problem and to provide a satellite communication system for connecting a calling terminal and a called terminal via one satellite line.

[0010]

According to the satellite communication system of the present invention, a plurality of exchanges connected to each other via a trunk line are provided.
Wherein at least one of the lowest-order switches comprises a first satellite
The second terminal accommodates the calling terminal connected to the terminal device,
Connected to satellite terminal equipment, both subscriber line and trunk line
Or to the subscriber line, using a satellite link, the calling terminal
Makes a call, the first satellite terminal equipment and the second satellite terminal equipment
During the location, means for setting the satellite line first, the called terminal
If it is not accommodated in the lowest exchange,
Only the second satellite terminal equipment among the star terminal equipment has the satellite loop.
Instructs to release line and is closest to destination
Connect the satellite line to a satellite terminal installed at the location
And set the section of the satellite line to the first satellite
Between the nearest satellite terminal equipment in the terminal station device called terminal
It is characterized by having means for changing .

As means for changing the section, means for performing satellite line setting processing in accordance with an instruction from the exchange may be provided separately from the exchange, or may be provided for each of the plurality of exchanges.
Exchange is a satellite link-ku, which houses via a satellite link to the destination terminal
It is also possible to adopt a configuration in which a change process is performed between them .

[0012]

When the terminal accommodating the satellite line communicates, or when a part of the trunk line from the originating exchange to the destination exchange passes through the satellite line, the exchange establishes the originating terminal in a plurality of satellite circuit sections. Information for identifying the line used by the satellite terminal device closest to, or information for identifying the line used by the satellite terminal device closest to the destination terminal in a plurality of sections of the satellite line, Alternatively, both pieces of information are notified to the next exchange, and a satellite line for directly connecting the satellite terminal device closest to the calling terminal and the satellite terminal device closest to the called terminal is set.

[0013]

FIG. 1 is a block diagram showing a satellite communication system according to a first embodiment of the present invention, and FIG. 2 is a line connection sequence diagram in the case where a satellite line is used as a relay line. FIG. 3 is a diagram showing a format example of a call connection control signal transmitted and received between exchanges.

The terminal 41 is connected to the exchange 31 by a satellite line set by the satellite terminal units 51 and 52, and the terminal 42 is connected to the exchange 31 by a terrestrial line. Also,
The terminal 43 is connected to the exchange 33 by a satellite line set by the satellite terminal units 55 and 56, and the terminal 44 is connected to the exchange 33 by a terrestrial line. Exchanges 31, 33
Manages the attributes of the connected terminals, and executes a satellite line setting request process each time the satellite line accommodating terminal communicates.

A terminal 41 accommodated by a satellite line makes a call,
An example of a connection process when a call is received at a terminal 43 accommodated by a satellite line via a relay section by a satellite line will be described.
Note that the subscriber signal line 111 is set before the terminal 41 makes a call and the call setting signal is sent to the exchange 31. The subscriber signal line 111 is set before the call setting signal for notifying the terminal 43 of the incoming call is transmitted from the exchange 32. It is assumed that the user signal line 112 is set.

When the terminal 41 originates a call, it transmits a call setting signal to the exchange 31 through the subscriber signal line 111. The exchange 31 sends a request for setting a satellite line having a required line speed between the satellite terminal units 51 and 52 through the line control line 61 based on the received call setting signal.
Notify to The satellite line control device 20 transmits an instruction for setting the subscriber information line 101 to the satellite terminal devices 51 and 52 via the satellite line control line 71. Upon starting transmission / reception of the designated satellite channel, the satellite terminal devices 51 and 52 notify the satellite channel control device 20 of a setting completion notification. The satellite line control device 20 includes satellite terminal devices 51 and 5.
When the completion signal is received from both of them, the exchange 31 is notified that the line setting request has been completed. Exchange 31
Receives the completion signal from the satellite line control device 20, selects the relay section by the satellite line as the relay line toward the exchange 33 accommodating the destination terminal, and switches to the exchange 32 that executes the connection processing of the relay section by the satellite line. , A call connection signal is transmitted through the relay signal line 130.

The contents notified from the exchange 31 to the exchange 32 include, as shown in FIG. 3, the line number of the selected relay information line, the subscriber number of the calling terminal, the subscriber number of the called terminal, and Originating satellite terminal device number for identifying the line used by the nearby satellite terminal device, originating satellite terminal device information line number, destination satellite for identifying the line used by the satellite terminal device closest to the destination terminal The exchange 32, which has received the call setting signal including the terminal unit number, the destination satellite terminal unit information line number, and the required information line speed, selects the exchange 33 as the connection destination of the trunk line from the destination terminal subscriber number. Further, the line used by the satellite terminal device 51 indicated by the originating satellite terminal device number and the originating satellite terminal device information line number and the exchange 33 which is the satellite terminal device closest to the destination terminal at present. The satellite line controller 2 is connected through a line control line 62 so that the line of the connected satellite terminal device 54 is connected by a satellite line.
Send a connection request to 0. The satellite line control device 20 transmits a release instruction of the subscriber information line 101 to the satellite terminal device 52 in order to change the setting of the subscriber information line 101 by the satellite line to the satellite line 102, and the satellite terminal device 54 , A satellite line 102 via a satellite line control line 71, 72.
To send the setting instruction. The satellite terminal device 52 notifies the satellite line control device 20 of a completion signal when transmission / reception of the designated satellite line is stopped and when the satellite terminal device 54 starts transmission / reception of the designated satellite line. . Upon receiving the completion signals from both the satellite terminal devices 52 and 54, the satellite channel control device 20 notifies the exchange 32 that the requested processing has been completed. When the exchange 32 receives the completion signal from the satellite channel controller 20, it sends a call connection signal to the exchange 33. The originating satellite terminal station device number and the originating satellite terminal station information line number transmitted at this time are the numbers received by the exchange 32 from the exchange 31. The destination satellite terminal device number and the destination satellite terminal information line number are changed to the line number used by the satellite terminal device 54.

The exchange 33, which has received the call connection signal, identifies whether the destination terminal is accommodated by a satellite line,
If the terminating terminal is a terrestrial line accommodation terminal, a normal incoming connection process is executed. If the terminating terminal is a satellite line accommodating terminal and the route from the calling terminal has already passed through the line section of the satellite line, the conventional incoming connection process will select a new line section of the satellite line. Become. In this embodiment, a section for setting a satellite line is changed instead of newly selecting a section for setting a satellite line. That is, the exchange 33 changes the section for setting the satellite line between the satellite terminal device closest to the calling terminal indicated by the received call connection signal and the satellite terminal device connected to the called terminal. To
An instruction is given to the satellite line control device 20 via the line control line 63. If the destination terminal is a satellite line accommodating terminal and the route from the calling terminal is only the line section of the terrestrial line, the exchange 3 which is the satellite terminal device closest to the calling terminal.
A request is made to the satellite channel control device 20 to set up a satellite channel between the satellite terminal device 55 connected to No. 3 and the satellite terminal device connected to the destination terminal.

In the case of the example shown in FIG.
Is a satellite line accommodating terminal, which passes through the satellite line 102. Therefore, the setting section of the satellite line is changed between the satellite terminal device 56 which is the satellite terminal device closest to the called terminal and the satellite terminal device 51 closest to the calling terminal indicated in the received call connection signal. The exchange 33 requests the satellite line controller 20 to perform the operation. The satellite line control device 20 includes the exchange 3
2 in the same way as the request from
Is performed, and upon completion thereof, a completion signal is notified to the exchange 33. When the exchange 33 receives the completion signal, the exchange 33 passes through the subscriber signal line 112 and
A call setting signal for notifying the incoming call is transmitted to the terminal 43. The terminal 43 transmits a response signal indicating a response to the call setting signal to the exchange 33. This response signal is transmitted to the relay signal line 13
0, the terminal 41 is notified via the exchanges 32 and 31 and the subscriber signal line 111. As a result, the terminal 41 and the terminal 43 start transmitting and receiving terminal information via the satellite line 103 that directly connects the terminals 41 and 43.

In the case where only the terrestrial trunk line is used between the exchanges 31 and 33, the transit exchange performs the same processing as the ground connection relay connection processing, and connects the call from the preceding exchange. From the signal, information for identifying the line used by the satellite terminal device closest to the calling terminal, information for identifying the line used by the satellite terminal device closest to the called terminal, and The information for identifying the line used by the nearest satellite terminal equipment is taken out and transferred to the next exchange.

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

As described above, according to the satellite communication system of the present invention, the satellite terminal station closest to the originating terminal and the satellite terminal station closest to the destination terminal do not pass through a section of a plurality of satellite lines. You can set up a satellite line that connects directly to.
Therefore, there is an effect that the satellite line can be effectively used and the communication quality can be prevented from deteriorating due to passing through a plurality of satellite lines.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a satellite communication system according to a first embodiment of the present invention.

FIG. 2 is a line connection sequence diagram in the case where a satellite line is used as a relay line.

FIG. 3 is a diagram showing a format example of a call connection control signal transmitted and received between exchanges.

Fig. 4 Uses satellite line for both subscriber line and trunk line
FIG. 2 is a block diagram showing a possible conventional satellite communication system.

[Fig. 5] Line when passing through a relay line by ground line
The figure which shows the example of a connection sequence.

Continuation of front page (72) Inventor Akira Kurokawa 1-6-6 Uchisaiwaicho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-63-175562 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B ^7/ 14-7/22

Claims (1)

(57) [Claims] 1. A system comprising a plurality of exchanges connected to each other via a trunk line , wherein at least one of the least significant exchanges is connected to a first satellite terminal equipment.
And a second satellite terminal.
Connected to the central office and connected to both the subscriber line and the trunk line or to the subscriber line.
In a satellite communication system using a star line, when the calling terminal makes a call, a first satellite terminal device and a second
Means for first setting up satellite links between satellite terminal equipment
And the destination terminal is not accommodated in the lowest exchange
And only the second satellite terminal device among the satellite terminal devices
Instructs to release the satellite link, and
The satellite terminal installed at the position closest to
Command to connect the line, and set the section of the satellite line,
Satellite communication method characterized by comprising means for changing between the nearest satellite terminal apparatus to the first satellite terminal equipment and the destination terminal.