JPH08102705A - Allocation system for satellite communication circuit - Google Patents

Abstract

PURPOSE: To improve the using efficiency of a satellite communication circuit by using a single carrier at each station in an allocation system of the satellite communication circuit. CONSTITUTION: This allocation system includes a master station 1, the slave stations 3, 4 and 5, and a communication satellite 2. The station 1 transmits the transmission permission timing (token frames) decided for each slave station to all stations 3 to 5 via the satellite 2. Each of these slave stations receives its own transmission permission signal and then performs the transmission control only when it has the will of transmission.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite communication line allocating system, and more particularly to a system for allocating a communication line between a plurality of slave stations and a master station, in which a single carrier is sequentially used for each station to increase the line height ratio. is there.

[0002]

2. Description of the Related Art In the conventional communication line allocation method between a slave station and a master station in satellite communication, DAMA is generally used to request a line allocation to the master station whenever a transmission request is made to the slave station.
(Demand Assignment Multip
le Access) method (for example, described in "Introduction to Overseas Satellite Communication" edited by The Institute of Electronics, Communication and Information Engineers of Japan) or TDM that gives transmission timing specified by the parent station to all stations in advance.
A (Time Division Multiple)
Access method (for example, "digital satellite communication")
(Described in industrial books) and the like are well known, and these are intended to improve the utilization efficiency of lines by sequentially using a single carrier at each station.

[0003]

The conventional satellite communication line allocation system has the following problems.

In the above-mentioned DAMA method, every time a transmission intention is generated in the slave station, a line allocation request is issued to the master station until a line allocation request is transmitted from the slave station until a line allocation instruction is given. There is a problem that the delay time of the round-trip satellite circuit that occurs in 1) causes a decrease in the circuit efficiency and that the management equipment of the master station becomes complicated because the master station needs to manage all the slave stations.

Further, in the TDMA system, since the transmission timing designated by the master station is given to all stations in advance, the slave stations are always periodically assigned with transmission slots, and therefore there are slave stations which do not request transmission. In this case, there was a problem that the line efficiency was lowered.

[0006]

The satellite communication system of the present invention is a satellite communication line allocation system for allocating communication lines for communicating from a plurality of slave stations to a master station via a satellite. Transmit a token frame in which a transmission permission signal having a different identification code for each slave station is arranged by using, and the slave station transmits to the master station only when the transmission permission signal for the own station in the token frame is received. To send.

[0007]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a satellite communication system using the present invention. The master station 1 transmits a signal transmitted from a token frame transmitter that generates a token frame to all the plurality of slave stations (3 stations for ease of explanation) 3, 4 and 5 via the satellite 2. To do. As will be described in detail later, the token frame has a predetermined time interval within one frame,
Each slave station has a corresponding transmission permission bit. This transmission permission bit can be easily provided by giving a different identification code to each station, for example. Slave station 3,
When the token frame is received and the transmission right is sent to its own station, the token frames 4 and 5 perform the transmission if the transmission intention is given.
Note that the number of slave stations of the present invention is not limited to three, and naturally, it can be applied to a large number of slave stations.

FIG. 2 is a diagram showing the structure of the token frame of the present invention. The token frame sequentially gives a transmission right to each slave station by a transmission permission bit at an interval of 250 mS which is one round trip propagation delay time required from the earth station of the satellite line to the earth station via the satellite. 250 here
The mS interval is necessary because all slave stations detect it when the slave station that has the transmission right transmits, and do not transmit even if the local station has the transmission right and is willing to transmit. Becomes

Further, it is possible to deal with the increase or decrease in the number of slave stations by changing the structure of the token frame. In the present embodiment, the token frames are provided at 250 mS intervals, but the present invention is not limited to this and any other number may be used. However, when the interval becomes 250 mS or more, there is a drawback that it takes a long time from the token frame to the reception of the transmission right of the own station when the number of stations increases.

FIG. 3 is a diagram showing a timing chart of the present invention. In the figure, a slave station A having a transmission intention acquires data from the master station and simultaneously transmits data. Similarly, the slave station B, which is willing to transmit, cannot acquire the transmission right, and at the same time, detects the carrier transmitted by the slave station A, and therefore cannot transmit. The slave station C detects that the transmission of the slave station A has stopped, and the transmission right comes around, but since it has no intention to transmit, it does not transmit for another slave station.

In the second cycle, the slave station B does not perform transmission by another slave station, and since it becomes possible to obtain the transmission right, the slave station B transmits.

[0012]

As described above, according to the present invention, it is possible to improve the line efficiency by transmitting according to the timing of the transmission right indicated in the token frame from the master station, if the transmission is desired. it can.

Particularly, it is effective to use this method as a means for rotating the video transmission right of the TV conference system, which is frequently called by the slave station, and also as a means for rotating the audio transmission right of the telephone conference system. Is.

Further, the power consumption can be reduced by utilizing the data collection of the telemeter which generates data intermittently.

Further, it has an effect that it can be applied to packet communication having a relatively long packet length.

[Brief description of drawings]

FIG. 1 is a block diagram according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a token frame of the present invention.

FIG. 3 is a diagram showing a data transmission sequence of the present invention.

[Explanation of symbols]

 1 Parent station 2 Communication satellite 3 Child station A 4 Child station B 5 Child station C

Claims (3)

[Claims] 1. A satellite communication line allocation method for allocating a communication line for communicating with a master station via a satellite from a plurality of slave stations, wherein the master station uses an arbitrary single carrier to identify each slave station differently. Transmitting data consisting of a token frame in which a transmission permission signal having a code is arranged to all the slave stations, and the slave station transmits to the master station only when receiving a transmission permission signal corresponding to its own station in the token frame. A satellite communication line allocation method characterized by transmitting data to each other. 2. The satellite communication according to claim 1, wherein in the token frame, a transmission permission signal for each slave station is repeatedly arranged in a predetermined order for each slave station at a predetermined time interval. Circuit allocation method. 3. The satellite communication line allocation system according to claim 2, wherein the predetermined time interval is equal to or longer than a time required for one round trip of the satellite line.