JPH06169275A - Satellite communication system - Google Patents

Abstract

(57) [Abstract] [Purpose] In a satellite communication system in which a certain frequency band is time-divided and used with other satellite communication systems, the efficient use of the frequency band and the flexible operation of the system are intended. [Structure] A unit that divides and processes transmission data into blocks that are transmission units, and observes the usage status of the frequency band.
A master station having a determining means, a means for controlling transmission / stop of transmission of a signal according to its use state, and a means for automatically scheduling transmission data in accordance with the transmission / stop of transmission of a signal, It is composed of a plurality of slave stations equipped with a means for constantly receiving a transmission block that is discontinuously transmitted in time according to the usage state of the frequency band and assembling the original data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite communication system that uses a fixed frequency band in a time division manner with other satellite communication systems.

[0002]

2. Description of the Related Art Conventionally, when a plurality of satellite communication systems use a constant frequency band by time division, from the viewpoint of allocation of use time of the frequency band, (1) a fixed number determined by each satellite communication system provider. In units of hours, and
There are two methods, a method of using the frequency band by fixed time allocation and a method of (2) a method of allocating the usage time of the frequency band according to the usage request of each dependent station.

The method (2) is a method in which the central station allocates an idle time to each subordinate station and uses the frequency band (centralized control method). Is provided with means for accumulating empty channel (frequency band) information, and based on this information, each station uses an empty channel, and notifies other stations of the use of the frequency band by a common signal channel. The other station that has received the notification updates the free channel information of its own station and is classified as a system (distributed control system) for the next transmission.

[0004]

However, in the method in which a plurality of satellite communication systems use a fixed frequency band by time division, in the above two methods, in the method (1), the time in which the frequency band is used in advance is used. There was a problem that the band had to be reserved, the usage time was fixed, and the frequency band could not be used suddenly.

In the method (2),
Whenever the frequency band is used, the central station is inquired about the availability of the frequency band each time,
There is a problem that some adjustment is required such as notifying another station that the frequency band is to be used, and a communication means for that purpose must be provided.

In any of the methods (1) and (2), when the frequency band is suddenly used, some kind of adjustment such as reservation or notification is necessary with other stations. There is a problem that efficient use of bandwidth and agile operation of the system are impossible.

The present invention has been made to solve the above problems, and an object of the present invention is to make a reservation or a reservation in a satellite communication system in which a fixed frequency band is used in a time division manner among a plurality of satellite communication systems. It is to provide a technology that enables efficient use of the frequency band and agile operation of the system without requiring any adjustment such as notification.

The above and other objects and novel features of the present invention will become apparent from the description of the present invention and the accompanying drawings.

[0009]

To achieve the above object, in a satellite communication system that uses a fixed frequency band in time division with a plurality of other satellite communication systems, transmission data is divided into blocks of transmission units. Means, means for observing / determining the use state of whether or not transmission is possible using the frequency band, means for controlling transmission / stop of signal transmission according to the use state, and signal transmission -A master station having means for scheduling transmission data in response to suspension of transmission, and a block of data that is discontinuously transmitted in time according to the usage state of the frequency band concerned is constantly received, and the original data is restored. It is characterized by comprising a plurality of slave stations having a means for assembling.

[0010]

According to the above-mentioned means, it is possible to observe the usage state of the frequency band used by time division with other plural satellite communication systems, and judge whether the own satellite communication system can use the frequency band or not. Control the transmission / stop of transmission, and automatically rearrange the transmission schedule, so that the frequency band can be used efficiently, and it can be coordinated with other multi-satellite communication systems via human hands. It can be done flexibly without.

[0011]

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

FIG. 1 is a schematic configuration diagram showing a schematic configuration of an embodiment of a satellite communication system according to the present invention.

As shown in FIG. 1, the satellite communication system of this embodiment is a satellite communication system that transmits transmission data from a master station 100 to a plurality of slave stations 110 and 120 via a satellite 130, and an earth station 140. And a certain frequency band is shared with another satellite communication system including the earth station 150.

The master station 100 observes a usage state of the frequency band, an observing section 101, a judging section 102 for judging whether or not the master station can transmit, and a schedule rearrangement flexibly according to the judgment result. -Scheduler 103 that manages and rewrites the schedule management file 104
And a transmission data file 10 for storing transmission data
5, the transmission data is divided into blocks, and a block processing unit 106 and a transmission control unit 107 that perform processing such as adding a header are included.

Each unit can be realized by an existing central processing unit (CPU).

The slave stations 110 and 120 are turned on when an error is included in the received block and a reception block 111, which is representative of the slave station 110 (NG) status. 112, a storage unit 113 that stores received blocks, a timer 114, an output unit 115 that outputs received data, and a receiving terminal system (display unit) 116.

FIG. 2 is a flow chart for explaining the operation of the master station 100.

FIG. 3 is a flow chart for explaining the operation in slave station 110.

First, an operation example of the master station 100 will be described with reference to the flowchart of FIG.

After the operation of the system of this embodiment is started (step 201), the observing section 101 first observes the use condition of the frequency band by means of observing the received signal waveform and judges the observation result. The data is transferred to the unit 102 (step 202). The determination unit 102 determines whether there is data waiting to be transmitted (step 203), and if there is data waiting to be transmitted, the determination unit 102 determines whether or not the frequency band is in a usable state in a certain time period. Yes (Step 20)
4).

1 if the determination result of the determination unit 102 is that transmission is possible
Send the block. (Step 205).

If the determination result of the determination unit 102 is NO, that is, if the frequency band is unusable, the transmission schedule is rearranged (step 206).

After the transmission of one block, if the next determination result is also transmittable, the next one block is transmitted. Next, it is determined whether the transmission is to be continued or ended (step 207), and if there is no data to be transmitted, the transmission is stopped (step 20).
8). Then, it is judged whether the operation is continued or ended (step 20).
9) If the operation is completed (YES), the operation is stopped (step 210). If the operation is continued (NO), the process returns to step 203 and the operation flow is repeated.

In the operation example shown in FIG. 2, the time required to transmit one block and the determination time period are the same.

The scheduler 103 transfers the data to be transmitted from the transmission data file 105 to the block processing unit 106 according to the information in the schedule management file 104.

The block processing unit 106 divides the transmission data into blocks and performs processing such as adding a header. If the determination result of the determination unit 102 indicates that transmission is possible, the scheduler 10
3 instructs the transmission controller 107 to transmit a signal, waits for the next determination result, and transmits the next block if transmission is possible.

When the transmission data is assigned to that time and the determination result of the determination unit 102 indicates that transmission is not possible, the scheduler 103 makes the frequency band available for the time of rearranging the schedule, for example. Send as soon as possible. Turn at the end of the schedule.

As the data to be rearranged in the schedule, the data of the untransmitted portion of the transmission data is newly added to 1
Reassign the schedule as one data. All data that was being sent is relocated to the schedule.

For example, a certain priority order is determined, and the schedule is rearranged according to a predetermined rule.
Rewrite the schedule management file 104.

Next, using the flow chart of FIG.
An operation example in the slave station 110 will be described.

System operation starts (step 301)
After that, the receiving unit 111 is always in a receivable state (step 302). The receiving unit 111 determines whether or not there is an error in the reception block for each reception of one block (step 303) (step 304). When an error is detected, the NG status 112 is turned on (step 3).
05).

It is also determined whether the received block is the last block of transmitted data (step 30).
6) Then, it is determined whether or not there is an NG status (step 307). If there is no NG status (off), the reception is completed (step 309), and if there is (on), the data is discarded, a message to that effect is displayed on the receiving terminal system 116, and reception is performed. Return to the waiting state (step 302).

After the reception is completed (step 309), it is judged whether the operation is continued or stopped (step 310). If YES, the operation is stopped (step 311), and if NO,
The process returns to the reception waiting state (step 302).

If all the blocks of the transmitted data are complete and no error is detected in the reception block, the reception data is completed and output from the output unit 115 to the reception terminal system 116.

When the last block of the transmitted data is received and the NG status 112 is on, the storage unit 113 discards the received data and displays the fact to the receiving terminal system 116.

In addition, the timer 114 is provided in the storage unit 113 to discard the received data which has timed out, and prevents the block from being permanently stored when the last block of the transmitted data is not received due to a reception error. To do.

The present invention has been specifically described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Is.

[0038]

As described above, according to the present invention,
Controlling transmission / transmission stop by observing the usage status of the frequency band used by time division with other satellite communication systems and determining whether the satellite communication system can use the frequency band or not. Since the transmission schedule is automatically rearranged, efficient use of the frequency band can be achieved, and it can be flexibly performed without manual adjustment with other multi-satellite communication systems.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a schematic configuration of an embodiment of a satellite communication system according to the present invention.

FIG. 2 is a flowchart for explaining the operation of the master station of this embodiment.

FIG. 3 is a flowchart for explaining the operation of the slave station according to the present embodiment.

[Explanation of symbols]

100 ... Parent station, 101 ... Observing section, 102 ... Judgment section, 10
3 ... Scheduler, 104 ... Schedule management file, 105 ... Transmission data file, 106 ... Block processing unit, 107 ... Transmission control unit, 110, 120 ... Slave station, 1
11 ... Receiving unit, 112 ... NG status, 113 ... Storage unit, 114 ... Timer, 115 ... Output unit, 116 ... Receiving terminal system, 130 ... Satellite, 140, 150 ... Earth station.

Continuation of front page (72) Inventor Shinsaku Okamura 3-3 Toyosu, Koto-ku, Tokyo NTT Data Communications Corp.

Claims (1)

[Claims] 1. In a satellite communication system that uses a fixed frequency band in a time division manner with another plurality of satellite communication systems, each earth station divides transmission data into blocks of a transmission unit, and the frequency band. A means for observing / determining the usage status of whether transmission is possible or not, using a means for controlling the transmission / stop of the signal according to the usage status, and A master station having means for scheduling transmission data;
A satellite communication system comprising a plurality of slave stations having means for constantly receiving data blocks sent discontinuously in time according to the use state of the frequency band and assembling the data into original data.