JPS61105133A - Time division multiple access satellite communication system - Google Patents

Abstract

PURPOSE:To attain burst time plan switching by allowing a code transmission means to operate and obtain a transmission timing when a transmission code of the own station is transmitted depending on the number of multi-frame and the frame interval of a prescribed number when a master main reference station transmits the transmission code. CONSTITUTION:A frame transmission circuit 3 in synchronization with a transmission multi-frame with a transmission timing signal S5 from a transmission timing generation circuit 4 inputs a code reception multi-frame number S4 representing a reception multi- frame number (n) when a change preparation command code is commanded by a transmission code selection signal S3 from a code reception circuit 1 and the circuit 4 transmits the change preparation command code to all stations controlled by the own station by using the multiframe of transmission multi-frame number (n+12) formed by adding 12 to the said number. The main reference station synchronizes the internal local counter with the number of a count-down start code transmitted from the master main reference station and transmits the count-down code of a count-down number 31 in the transmission multi-frame after 3Tm+Dn next to the multi-frame in which the count-down number 0 is transmitted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a time division multiple access satellite communication system. In particular, it relates to the timing of transmitting the transmission code of the main reference station in synchronization with the transmission timing of the transmission code of the master main reference station in the burst time plan switching circuit of the main reference station that follows the master main reference station.

[Conventional technology]

Generally, burst time plan switching is performed using the following procedure.

Step (1) The master main reference station transmits a burst time plan switching start code consisting of 32 steps (1 multiframe/step) from countdown numbers 31 to 0 to the main reference station.

Step (2) Master main reference station is countdown number 0
Twelve multiframes (hereinafter referred to as T) after the next multiframe timing at which the burst time plan switching start code was sent, the change preparation command code is sent to all stations controlled by the local station.

The main reference station synchronizes its own local counter with the countdown number included in the burst time plan switching start code sent from the master main reference station, and synchronizes its own local counter with the multiframe timing next to the multiframe in which countdown number 0 is received. After 3T and +D, the station sends a change preparation command code to all stations controlled by the local station.

Step (3) The master main reference station or each station controlled by the main reference station sends a change ready sign to the master main reference station or the main reference station if the new burst time plan after switching is ready.

Step (4) When the main reference station receives the change preparation completion code from all the stations it controls, it sends the change preparation completion code to the master main reference station.

Step (5) When the master main reference station receives change ready codes from all the stations it controls and the main reference station, the master main reference station sends the main reference station a countdown number from 31 to 0 at a predetermined timing. A countdown start code consisting of 32 steps is sent.

Step (6) The master main reference station transmits the countdown number 3 from 31 to 0 after 12T from the next multi-frame timing that sent the counterdown start code with countdown number 0 to all stations controlled by the master main reference station.
Sends out a two-step countdown code.

The main reference station synchronizes its internal local counter with the countdown number included in the countdown start code sent from the master main reference station to all the stations it controls, and receives countdown number O. 37 from the next multiframe timing of multiframe
After ゜+D, l, a countdown code consisting of 32 steps from countdown numbers 31 to O is sent out.

Step (7) The burst time plans on the transmitting side and the receiving side in the master main reference station or the burst time plan switching participating station controlled by the main reference station are changed at the following timing.

This is performed 3 Tea'' Dn from the next multiframe timing of the multiframe in which the countdown code of countdown number O is received on the transmitting side.

Receiving side 2 127. from the next multiframe timing of the multiframe that received the countdown code with countdown number 0. will be done later.

Here, in the prior art, the main reference station receives the burst time plan switching start code with countdown number 0 from the master main reference station at a timing 3 T m + D n after the next multi-frame timing of the multi-code and with countdown number O. A special timing generation circuit was used to generate the timing 3Tffi+Dffi after the next multiframe timing of the multiframe that receives the countdown start code, and the timing for sending out the change preparation command code and countdown code was controlled. .

FIG. 2 is a block diagram of a burst time plan switching circuit for a conventional time division multiple access satellite communication system. Second
In the figure, the code receiving circuit 1 of the main reference station outputs the value S of D7 to the timing generation circuit 5, and the burst time plan switching start code or countdown start code of countdown number 0 from the master main reference station is output. At the next multiframe timing of the received multiframe, the code reception timing signal Sll is output to the timing generation circuit 5, and at the same time, to the code transmission circuit 3,
A transmission code selection signal S3 indicating whether the code to be transmitted next is a change preparation command code or a countdown code is output.

The timing generation circuit 5 starts a counter of 3T+D7 using the code reception timing signal S8 given from the code reception circuit 1 and the symbol clock signal S from the reception timing generation circuit 2, and when the count ends, Code transmission timing Sil+ for the code transmission circuit 3
Output.

The code transmission circuit 3 receives the code transmission timing signal S from the timing generation circuit 5. and transmitting code selection signal S from code receiving circuit 1 to send out a transmission signal S.

[Problem that the invention seeks to solve]

However, in the conventional burst time plan switching circuit in such a main reference station, 3T
37. from the next multiframe timing of the multiframe receiving the countdown start code of l + o n and countdown number 0. A special timing generation circuit 5 is required to generate the timing of +D, .

Therefore, there is a drawback that the number of ink face signals between circuits increases, resulting in an increase in circuit scale.

The present invention solves the above-mentioned drawbacks by providing a burst time plan switching circuit for a time division multiple access satellite communication system that does not require a special timing generation circuit, has fewer ink face signals between circuits, and has a small circuit scale. The purpose is to provide.

[Means for solving problems]

The present invention includes a master main reference station that transmits multiframes including transmission codes at predetermined multiframe intervals, a main reference station that follows this master main reference station, and a plurality of slave stations controlled by this main reference station, The main reference station has a code receiving means for analyzing the transmitted code from the master main reference station and confirming the reception timing of the transmitted code, and receives the analysis result of the transmitted code from the code receiving means and transmits it to the own station. code transmitting means for transmitting a transmission code to the plurality of slave stations in synchronization with the reception timing of the transmission code of the master main reference station, and the main reference station and the slave stations have a burst time plan in a time division multiple access frame. In a time division multiple access satellite communication system, the code receiving means includes a code transmitted from the master main reference station, in a time division multiple access satellite communication system, which is equipped with a means for changing the above at the same time on all stations without momentary line interruption based on the command of the master main reference station. It is characterized in that it includes a detection means for detecting a multi-frame number, and the code transmission means includes means for calculating the transmission timing of the transmission code of its own station from the detection result of the detection means and the predetermined number of multi-frame intervals. shall be.

[Effect]

In the present invention, the code receiving means detects the number of a multi-frame including a transmission code from a master main reference station, and the code transmitting means detects the number of a multi-frame including a transmission code from a master main reference station based on this multi-frame number and a predetermined number of frame intervals at which the master main reference station sends a transmission code. By calculating and determining the sending timing at which the station sends its own transmission code, it is possible to switch burst time plans without the need for a special timing generation circuit, with fewer ink face signals between circuits, and with a small circuit. It can be carried out.

〔Example〕

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

FIG. 1 is a block diagram of a burst time plan switching circuit for a time division multiple access satellite communication system according to an embodiment of the present invention. In FIG. 1, a received code S is connected to the input of a code receiving circuit l from outside the figure.

Reception timing signal S2 from reception timing generation circuit 2
is connected to the timing signal input of the code receiving circuit 1 and synchronized with the received multiframe. A transmission code selection signal S3 and a code reception multiframe number S4 from the frame reception circuit 1 are connected to inputs of the code transmission circuit 3, respectively. A transmission timing signal S from the transmission timing generation circuit 4 is connected to a timing signal input of the code transmission circuit 3 and synchronized with the transmission multiframe. Frame transmission circuit 3
The transmission frame S6 is sent out from the diagram.

Countdown end signal S from code receiving circuit 1.

is connected to the reception timing generation circuit 2 and the reception timing generation circuit 4, and generates the burst time plan switching timing for the transmission side and the reception side.

The operation of the burst time plan switching circuit of the time division multiple access satellite communication system having such a configuration will be explained. 1st
In the figure, the code reception circuit 1 synchronized with the received multiframe by the reception timing signal S2 from the reception timing generation circuit 2 of the main reference station uses an internal local counter to match the countdown number of the burst time plan switching start code from the master main reference station. At the same time, the received multiframe number S4 indicating the received multiframe number n of the multiframe in which the burst time plan switching start code with countdown number 0 is received is outputted to the code transmitting circuit 3, and at the same time, the code to be sent next is changed. It also outputs a sending code selection signal S indicating that it is a preparation command code.

Transmission timing signal S from transmission timing generation circuit 4
5, the frame transmitting circuit 3 synchronized with the transmitted multiframe receives the transmission code selection signal S3 from the code receiving circuit 1.
When the change preparation command code is specified, input the code reception multiframe number S4 indicating the reception multiframe number n, and add 12 to that value to control the own station using the multiframe of the transmission multiframe number n + 12. A change preparation command code is sent to all stations in the station.

When the code receiving circuit 1 receives change ready codes from all stations controlled by its own station, it sends a sending code selection signal S indicating that the next code to be sent is the change ready code. It is output to the code transmission circuit 3. In the code transmitting circuit 3, when the change preparation completion code is designated by the sending code selection signal S3, the change preparation completion code is immediately sent out.

Next, in the code receiving circuit 1, the internal local counter is synchronized with the countdown number of the countdown start code from the master main reference station, and the received multiframe number n in which the countdown start code with countdown number 0 is received is sent to the code transmitter circuit 3. At the same time as the output, a transmission code selection signal S3 indicating that the next code to be transmitted is a countdown code is also output. In the code transmitting circuit 3, when a countdown code is instructed by the sending code selection signal S, a code receiving multiframe number S4 indicating the receiving multiframe number n is inputted, and 12 is added to that value to obtain the transmitting multiframe number. In the n+12 multiframe, the countdown code of O starts to be transmitted from the countdown number 31.

In the code receiving circuit 1, the internal local counter is synchronized with the countdown number of the countdown code sent from the master main reference station, and the countdown is performed using the next multiframe timing of the multiframe in which countdown number 0 is received as the countdown end timing. A termination signal S7 is output to the transmission timing generation circuit 4 and the reception timing signal input 2. The transmission timing generation circuit 4 and the reception timing generation circuit 2 generate burst time plan switching timings for the transmission side and reception side based on the countdown end signal S7. Since the means for generating the timing of 3T++++Dn for transmitting the change preparation command code or countdown code is basically the same, Fig. 3 shows a time chart from reception of the countdown start code to transmission of the countdown code. Accordingly, aTm +
The timing generation means for Dn will be explained.

At the main reference station, the internal local counter is synchronized with the countdown number of the countdown start code sent from the master main reference station, and 37 m ” D In the transmission multiframe after n, a countdown code with countdown number 31 is transmitted.The countdown code with countdown number 31 is the same multiframe on the time axis on the satellite as the countdown code with countdown number 31 transmitted by the master main reference station. It is generally well known that it is included in

It is also generally well known that the codes transmitted by the master main reference station and the main reference station with transmission multiframe number n are included in the same multiframe on the time axis on the satellite.

Therefore, the countdown code with the countdown number 31 sent by the master main reference station and the main reference station that are executing burst time plan switching must be sent in a multiframe with the same transmission multiframe number n for both stations.

On the other hand, the code sent by the master main reference station in a multiframe with transmission multiframe number n is received by the main reference station in a multiframe with reception multiframe number n, and conversely, the code sent by the main reference station in a multiframe with transmission multiframe number n The code must be received in a multiframe with reception multiframe number n of the master main reference station.

That is, if the main reference station receives a countdown start code with countdown number 0 from the master main reference station in a multiframe with reception multiframe number n, then the subsequent transmission multiframe will be 37m+D, and the next transmission multiframe will be transmission multiframe number n+12. Therefore, if the countdown code of countdown number 31 is transmitted in the transmission multiframe, it will match the countdown code of countdown number 31 transmitted by the master main reference station on the time axis of the satellite.

As described above, the present invention calculates the transmission multiframe number of the multiframe that transmits the countdown code from the reception multiframe number of the multiframe that receives the countdown start code of countdown number O, This is achieved using a circuit with simple arithmetic functions without the need for a special timing generation circuit.

〔Effect of the invention〕

As explained above, the present invention has the excellent effect of being able to perform burst time plan switching without using a conventional special timing generation circuit.

Further, the symbol clock supplied to the timing generation circuit shown in the conventional example is generally very high speed, and there are problems with stability due to noise and the like, and 3T.

If +D, . . . is expressed as a symbol, it will be several hundred blade symbols, and the problem of the counter circuit becoming large can be solved by this invention, which has the effect of realizing a highly stable and simple burst time plan switching circuit.

[Brief explanation of the drawing]

FIG. 1 shows a burst time plan switching circuit for a time division multiple access satellite communication system according to an embodiment of the present invention. Figure 2 shows a burst time plan switching circuit for a conventional time division multiple access satellite communication system. FIG. 3 is a time chart of each signal of the burst time plan switching circuit of the time division multiple access satellite communication system of the present invention. l... code receiving circuit, 2... receiving timing generating circuit, 3... code transmitting circuit, 4... transmitting timing generating circuit, S... receiving code, S2... receiving timing signal, S3... Sending code selection signal, S4... Code reception multi-frame number, SS... Transmission timing signal, S6... Transmission code, S,... Countdown end timing signal, S8... Code reception timing signal, S. ...Dl value, SIO...code sending timing signal, Sl+...symbol clock signal.

Claims (1)

[Claims] (1) A master main reference station that transmits multi-frames including transmission codes at predetermined multi-frame intervals, a main reference station that follows this master main reference station, and a plurality of slave stations controlled by this main reference station, The main reference station includes code receiving means for analyzing the transmitted code from the master main reference station and confirming the reception timing of the transmitted code, and inputting the analysis result of the transmitted code from this code receiving means.
code transmitting means for transmitting the transmission code of the own station to the plurality of slave stations in synchronization with the reception timing of the transmission code of the master main reference station; In a time division multiple access satellite communication system that is equipped with a means for changing the burst time plan at the same time on all stations without instantaneous line interruption based on commands from the master main reference station, the code receiving means receives a transmission from the master main reference station. a detecting means for detecting the number of a multi-frame including a code, and the code transmitting means includes a means for calculating the transmission timing of the own station's transmission code from the detection result of the detecting means and the predetermined number of multi-frame intervals. A time division multiple access satellite communication system characterized by: