JPH01165232A - Allocation request multiple access communication system for satellite communication - Google Patents

Abstract

PURPOSE:To suppress possibility to generate the collision of information from a terminal station to a master station at minimum by employing a system where transmission to the master station by a slot of random access system can be permitted only to a slave station designated by the master station. CONSTITUTION:The title system is the one where the master station designates the slave station (1-plural groups) to which the slot of random access system is permitted to use by the slot of time divisional multiplex system out of a large number of slave stations. Thereby, since only the terminal stations (2-7) groupdesignated by a central station 1 can perform the transmission to the central station 1 by using the slot of random access system, the number of the terminal stations possible to use the slot of random access system is limited, therefore, the possibility to generate the collision of the information from the terminal stations (2-7) to the central station 1 due to the the simultaneous usage of the slot of random access system by plural terminal stations can be suppressed at minimum.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to TDM (TDM) used in satellite communications.
ime Division Multiple (time division multiplex) method and allocation request multiple access (DAMA) using a random access method.
ignmentMultiple Access) communication method.

[Prior Art] Fig. 2 is a schematic configuration diagram showing a general satellite communication system. In Fig. 1, 1 is a central station (master station) having a central DAMA communication device, and 2 to 4 are terminal DAMA communication devices. Terminal stations (slave stations) 8 are communication satellites that relay lines between the central station 1 and the terminal stations 2 to 4.

The allocation request multiple access (hereinafter referred to as DAMA) communication method used in such a satellite communication system is performed as follows. In other words, a certain number of lines relayed by the communication satellite 8 are transmitted to the central station 1. When the central station 1 receives a line allocation request signal from each terminal station 2 to 4 via the above line, it uses a pair of frequencies in the common pool (for idle calls). When the call ends, the assignment is canceled and the line is returned to the pool. Such operations are performed each time a call occurs.

Also, in the AMA communication system as described above.

Information is transmitted from the central station l to each terminal station 2 to 4.

In the time division multiplexing (hereinafter referred to as TDM) method, information is transmitted from one slot to the other, while information is transmitted from each terminal station 2 to 4 to the central station 1 by a random access method. When information is generated, the slot is randomly used.

[Problems to be Solved by the Invention] By the way, in such an allocation request multiple access communication system for satellite communication, since each terminal station 2 to 4 uses slots at random, a plurality of pieces of information cannot be transmitted using one slot. There was a problem in that there was a possibility that information sent from the terminal stations 2 to 4 to the central station 1 would collide.

This invention was made to solve the above-mentioned problems, and provides an allocation request multiple access communication system for satellite communication that can reduce the possibility of information collision from a slave station to a master station. The purpose is to

[Means for Solving the Problems] In the allocation request multiple access communication system for satellite communication according to the present invention, a master station allocates a random access system slot among a large number of slave stations using a time division multiplex system slot 1-. This is used to designate a slave station (one or more groups) that is permitted to be used.

[Function] In the allocation request multiple access communication system for satellite communication according to the present invention, only the slave stations designated by the master station can transmit to the master station using slots of the random access system.

[Embodiment of the Invention] An embodiment of the invention will be described below with reference to the drawings. 1st
FIG. 1 is a schematic configuration diagram showing a communication satellite system for explaining an allocation request multiple access communication system for satellite communication according to an embodiment of the present invention. In FIG. 1, 1 is a central DA
Central station (master station) with MA communication equipment, 2 to 7 are terminal DA
It is a terminal station (slave station) with an MA communication device, and in Figure 1,
Although the communication satellite 8 is not shown in the figure, in reality, the lines between the central station 1° and the terminal stations 2 to 7 are relayed by the communication satellite 8. In addition, from the central station 1 to each terminal station 2 to 7
Transmission of information to the central station 1 is performed using TDM slots, while transmission of information from each terminal station 2 to 7 to the central station 1 is performed using a random access method.

In a satellite communication system as shown in FIG. 1, the DAMA borrowing method according to the present invention is carried out as follows.

Normal communication is carried out in exactly the same manner as the conventional communication system explained with reference to FIG. When the central station 1 receives a line allocation request signal from each terminal station 2 to 7 via the above line, it uses a pair of frequencies in the common pool (for idle calls). When the call ends, the 1 allocation is canceled and the line is returned to the pool.

In addition, in this embodiment, the central station 1 uses the TDM slot to specify a group of terminal stations among the terminal stations 2 to 7 that are permitted to use the random access slot, and transmits this information to each terminal station. Transmit to terminal stations 2-7. For example, as shown in FIG.

First group A consisting of terminal stations 2 to 4 and terminal stations 5 to 7
A second group B is set, and one of groups A and B is alternately designated at predetermined time intervals as a group to which use of slots in the random access system is permitted.

Then, each of the terminal stations 2 to 7 checks the information from the central station 1, determines whether the group to which it belongs can use the slot of the random access method, and determines whether the slot of the random access method can be used. , and if there is information to be transmitted to the central station 1, the information is transmitted to the central station 1 using a random access slot.

If no information is transmitted from the terminal stations 2 to 4 or 5 to 7, the central station 1 changes the group that is permitted to use the slot in the random access method after a predetermined period of time, and if no information is transmitted. If so, processing is performed using the normal DAMA communication method as described above.

In this way, according to this embodiment, only the terminal stations (2 to 7) designated as a group by the central station 1 are in a state where they can transmit to the central station 1 using the slots of the random access method. Therefore, the number of terminal stations that can use random access slots is limited, and unlike in the past, multiple terminal stations use random access slots at the same time, causing collisions of information from terminal stations 2 to 7 to central station 1. Is it possible?

becomes extremely low.

In the above embodiment, the number of terminal stations (slave stations) is six, but the number is not limited to six.

Further, although the number of groups is two, it is not limited to this. Further, although the number of terminal stations belonging to each group is three, the number is not limited to this, and any number of terminal stations may be one or more.

[Effects of the Invention] As described above, according to the present invention, only the slave stations specified by the master station are allowed to transmit to the master station using the random access slot. This has the effect of limiting the number of slave stations that can use the terminal station and extremely reducing the possibility of information collision from the terminal station to the master station.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a communication satellite system for explaining an allocation request multiple access communication system for satellite communication according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram showing a general satellite communication system. be. In the figure, 1--central station (master station), 2-7-- one terminal station (slave station), and 8--communication satellite. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A master station and a large number of slave stations are installed, and the time division multiplexing method is used to transmit information from the master station to each slave station, while the random access method is used to transmit information from each slave station to the master station. In the satellite communication allocation request multiple access communication system, when the master station receives a line allocation request signal from the slave station via a line relayed by a communication satellite, it selects and allocates an idle communication line. , an allocation request multiple access for satellite communication, characterized in that the master station specifies, by the time division multiplexing slot, which of the many slave stations is permitted to use the random access slot. Communication method.