JPH0345027A - Line assignment plan distribution system - Google Patents

Abstract

PURPOSE:To improve the flexibility of line setting by distributing each of plans being divisions of line assignment plan from a reference station to each earth station sequentially, detecting an error by each earth station every time it is distributed with the line assignment plane, and delivering again only the line assignment plan whose transmission fails to each earth station when the delivery is entirely finished. CONSTITUTION:A line assignment plan is divided into n-set of plans, a line assignment plan #1 to an earth station #1 is delivered through a CAC line of a TDMA frame #1 in a control frame #1, a line assignment plan #1 to an earth station #m is delivered through a CAC line of a TDMA frame #m,... and a line assignment plan #2 to an earth station #m is delivered through a CAC line of a TDMA frame #m in a control frame #2. In such a case, each earth station decides whether or not normal reception is implemented and the result of discrimination is informed to a reference station. A reference station receiving the notice of unnormal reception delivers only the line assignment plan to the earth station again. Thus, the time required for the line assignment plan change criterion is minimized, and the flexible line setting is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a line allocation plan delivery method, and more particularly to a line allocation plan delivery method used in a communication system that performs communication via a communication satellite.

(Prior art) T D is a multiple access system in which a large number of stations communicate with each other by transmitting signals on the same carrier frequency so that signals do not overlap in time.
MA (Time Divisional Mult
This is called the ipileAeces+) method. In this method, TDM of a certain length, which is the basic cycle of signal transmission and reception, is
Define the A frame and assign 1 in this frame.
The TDMA satellite communication method is an application of this method to communication via a satellite, in which communication is performed with a partner station using paired time positions (time slots).

In the TDMA satellite communication system, a reference station controls communication between multiple earth stations via control frames.A control line is used to exchange information between the reference station and the earth station to maintain zero line, and data One TDMA frame is created for each line, and several TDMA frames are combined as a control frame for line control.

Communication control is performed by periodically repeating the transmission of this control frame.

By the way, in the TDMA satellite communication system, the time position and time length of the above-mentioned time slot are assigned to each earth station as a line. When changing the time slot position and time length, that is, the line allocation to each station,
It is necessary to send out a newly determined line allocation plan (newly determined time slot positions and time lengths) from the reference station in advance.

The control line includes the so-called CDC line, which is a line for mainly performing synchronization control and plan control from the reference station to the earth station, and the line for requesting status information of each earth station, which is usually used to control the line plan. When a delivery is required, the line allocation plan will include a CAC line to be placed in its place, an SC line for each earth station to respond according to instructions from the reference station, and an SC line for reporting the requested status information of each earth station. M.C.
Includes lines, etc.

Referring to FIG. 4, the ITDMA frame includes a preamble part 6, a CDC line 7, a CAC line 8, and a postamble part 9 of the control line transmitted from the reference station to the earth station.
, and a preamble part 10 of a control line transmitted from the earth station to the reference station, an SC concave line 11, an MC line 12,
The postamble section 13, furthermore, the data line 14, etc., are warned.

Furthermore, one control frame consists of multiple (m questions in this example) T
DMA frames 15, 16. ..., it consists of 17 pieces.

Now, the procedure of the conventional line plan distribution system in the above-mentioned TDMA satellite communication system is carried out as follows.

That is, when it becomes necessary to deliver a line allocation plan, the reference station allocates the CAC lines of all TDMA frames to a certain station, continuously delivers the line allocation plan of the station, and distributes all the line allocation plans to the station. After this is completed, a response is requested from the station via the control line to confirm whether the station has received the data normally. When the reference station receives a response from the station that reception has failed, it resends the line allocation plan to the station.

In Fig. 5, which schematically shows the distribution of line allocation plans #1 to #n to the earth stations consisting of F□ (p is 1 to m, q
1 to n) is TDMA indicated by q for earth station #p
Line allocation plan #1 included in the CAC line in the frame
~#n, indicating that the line allocation plan for earth station #p is delivered during the period from control frames #1 to #r.

Referring to FIG. 5, in control frame #1 consisting of TDMA frames #1 to #m, first, in control frame #1, the CAC line in TDMA frames 1 to m is transmitted to a specific earth station p. transmits line allocation plans #1 to #m in control frame #2, and continues to control line allocation plans #'(m+1) to #2m on the CAC line of TDMA frames (m+l) to 2m to the same station p in control frame #2. flame#
Line allocation plans #(n-1), # for the same station p at r
Send n.

In this way, in the conventional method, each earth station transmits all line allocation plans in chronological order using the CAC line of the TDMA frame that constitutes the control frame, and receives a response that indicates normal reception from the earth station. After receiving the request, the line allocation plan was once again delivered to other earth stations.

Therefore, for example, due to a request to change the line allocation plan, etc.
When it becomes necessary to distribute the line allocation plan to all stations participating in the line, the base station repeats the above series of procedures until all earth stations receive the line allocation plan normally. After confirming that you are eligible, you will need to proceed with the plan change procedure.

(Problems to be Solved by the Invention) However, the above-mentioned conventional system has the following problems. In other words, in the conventional line allocation plan distribution method, especially in a satellite communication system with a large number of participating stations, when a line allocation change request occurs, the entire line allocation plan is delivered to each earth station using a control line. Later, we check the response from the relevant station to see if reception was successful or not. If reception fails, it must be redistributed to this nuclear layer, especially if the line condition of each earth station is not good. Sometimes, the reception of the line allocation plan tends to fail and the line allocation plan has to be re-delivered, and when there are many earth stations participating in the line, the time required to prepare for changing the line allocation plan increases, and sometimes the line allocation plan is It is possible that changes to the allocation plan may not be possible. This poses a problem in that it significantly impedes the flexibility of line settings that is expected of original TDMA satellite communications, which allows line settings to be easily made by simply instructing each earth station to change the line allocation plan.

Additionally, if such a situation is anticipated in advance, the system would need to be designed so that line allocation plans are delivered via terrestrial lines rather than satellite lines, which would require complicated procedures. There's a problem.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a line allocation plan delivery method that minimizes the time required for preparing to change a line allocation plan and maintains flexibility in line settings.

(Means for Solving the Problems) The present invention has the following means configuration to achieve the above object.

That is, in the line allocation plan delivery method according to the present invention, a plurality of earth stations communicate using lines allocated based on the time division multiple access (TDMA) method under control from the reference station via a communication satellite. In the line allocation plan distribution method in which a line allocation plan indicative of the line allocation is delivered to the earth station, the reference station sequentially delivers each of the divided plans obtained by dividing the line allocation plan to all of the earth stations. Then, the earth station responds to the reference station by performing error detection based on the received data, and informs the reference station whether or not normal reception is possible. The system is characterized in that only those divided plans that have not been normally received by the responding earth station are re-delivered.

(Function) Hereinafter, the function of the line allocation plan distribution system of the present invention having the above-mentioned means configuration will be explained.

In the present invention, in order to determine the allocation of lines (slots) for communication between a plurality of earth stations, a line allocation plan is divided, and each divided line allocation plan (divided plan) is sequentially allocated to all earth stations. The earth station determines whether normal reception is occurring based on the received data, and notifies the reference station of the determination result.The reference station receives notification that normal reception is not occurring. , only that line allocation plan is delivered again to the earth station.In other words, the present invention does not transmit a response regarding normal reception after the delivery of all line allocation plans to one earth station is completed, unlike the conventional method. Line allocation plans (divided) are sequentially delivered to all earth stations in parallel.Therefore, failures in line allocation plan delivery are minimized.

(Example) Hereinafter, an example of the line allocation plan delivery system of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the line allocation plan distribution method of the present invention, and is a diagram showing the procedure for sending a line allocation plan from the reference station to each earth station.

In this embodiment, when it becomes necessary to distribute a line allocation plan, the reference station instructs all earth stations #1 to #m to receive the previously allocated TDMA CAC line.

To deliver the line allocation plan from the reference station to each earth station, divide the line allocation plan into n parts and use the divided line allocation plan #
1 to #n are sequentially transmitted in parallel to earth stations #1 to #m, respectively.

FIG. 1 schematically shows TDMA frames from control frames #1 to #n, where Fp@(p is 1 to m, q is 1 to n
), F is the TDMA frame, p is 4m from earth station #1
, q is n included in the CAC line in the TDMA frame.
It means divided line allocation plans #1 to #n.

In other words, in control frame #1, TDMA frame #1
The CAC line of TDMA frame #2 has line allocation plan #1 for earth station #1, and the CAC line of TDMA frame #2 has line allocation plan #1 for earth station #2.
Line allocation plan #1 for earth station #m is delivered to the CAC line of frame #m, and in the next control frame #2, line allocation plan #1 for earth station #1 is delivered to the CAC line of TDMA frame #1. 2, line allocation plan #2 for earth station #2 is delivered to the CAC line of TDMA frame #2, and line allocation plan #2 for earth station #m is delivered to the CAC line of TDMA frame #m. Similarly, in control frame #3, line allocation plan #3 is used for earth stations #1 to #m, and in control frame #n,
Line allocation plan #n is delivered to earth stations #1 to #m, respectively. In this way, the distribution is repeated over the number of control frames n times until the final line allocation plan #n is distributed to all earth stations.

Each earth station is instructed to receive the line allocation plan from the reference station via the CDC line, and the earth station receives line allocation plan #1 from the reference station.
When the TDMA is delivered, the TDMA with the line allocation plan
Based on the error detection signal included in the other line of the frame, it is determined whether the reception was successful or not, and the determination result is notified to the reference station via the SC line. This procedure is repeated until the last line allocation plan #n.

When the reference station receives a response indicating that the reception of the line allocation plan has failed from the earth station, it sends only the line allocation plan that failed to be received once the delivery of the line allocation plan up to #n has been completed to all the earth stations. Deliver to the applicable earth station.

FIG. 2 schematically shows the connection of line allocation plans at each earth station #1 to #m, and Cpq is 0, which corresponds to F and Q in FIG. 1. For example, earth station # 1, the frame F11+F 12°Fl3.・・・
・Fl, line allocation plan C11, CI2. Similarly, at earth station #2, C13゜...C, fi is C21, C
22°C23,"' C2m is Cm at earth station #m
l 1 + C+m2 +C, 3, . . . C1° will be received.

Figure 3 shows that each of the line allocation plans delivered from the reference station to the earth stations #1 to #m via the CAC line is judged at the earth station as to whether or not it has been successfully received, and the results are sent to the SC.
In Fig. 6, which is a timing diagram showing the time until the information is transmitted to the reference station via the line, with the horizontal axis as the time axis, 1 is the reference station, 2 and 3 degrees 4.5 are the earth station #1, respectively. #2. #3
．． #m, F□ is the same frame as in FIG. 1, and A, , are responses from each earth station via the SC line corresponding to pea.

To be more specific, from reference station 1 to earth stations #1 and #2
．． #3. When line allocation plan #1 is delivered to #m via the CAC line of the TDMA frame, earth station #1
．． #2. #3. From #m, the response is A 11 ,
A21. It is sent to the reference station as A S 1 , A , 1 . Similarly, the response to the delivery of line allocation plan #2 is A12. A22. A 32. A
, becomes 2.

In the line allocation plan distribution method of the present invention, even if the line condition of each earth station is not good, the reference station only sends the line allocation plan for which normal reception was not received to the earth station that has issued the notification that normal reception was not performed. Since the network is re-delivered, if there are many earth stations participating in the line, the time required to prepare for changing the line allocation plan is extremely short. Therefore, it is possible to construct an efficient communication system by taking advantage of the flexibility of line installation, which is originally expected for TDMA satellite communication.

(Effects of the Invention) As explained above, the line allocation plan distribution method of the present invention sequentially delivers each of the plans obtained by dividing the line allocation plan from the reference station to each earth station, and each earth station receives this line allocation plan. Error detection is performed each time a delivery is made, and the reference station is notified whether the delivery was successful or not. Once all line allocation plans have been delivered, only the failed line allocation plans are reassigned to each earth station. , is being sent.

As a result, the success rate of line allocation plan delivery is improved, the time required to prepare line allocation plan changes is minimized, and line configuration flexibility is improved compared to traditional line allocation plan delivery methods. It has the advantage of being possible.

[Brief explanation of drawings]

FIG. 1 is an elliptical diagram of a control frame for delivering a line allocation plan from a reference station to each earth station, showing an embodiment of the present invention.
Figure 2 is a diagram showing the connection of reception line allocation plans at each earth station, Figure 3 is a diagram showing the delivery status of line allocation plans from the reference station to each ground station and the status of response notifications from each earth station to the reference station, Figure 4 shows TDM in TDMA system.
FIG. 5, a diagram schematically showing an A frame and a control frame, is a control frame configuration diagram in a conventional line allocation plan distribution system. 1...Reference station, 2-5...Earth station,
6.10...Preamble section, 7...
・CDC line, 8...CAC line, 9,1
3... Postamble section, 11...
SC line, 12...MC line, 14...
...Data line.

Claims (1)

[Claims] In order for a plurality of earth stations to communicate with each other using lines allocated based on a time division multiple access (TDMA) method controlled by a reference station via a communication satellite, the reference station creates a line allocation plan indicating the allocation of the lines. In the line allocation plan delivery method for delivering to the earth station, the reference station sequentially delivers each of the divided plans obtained by dividing the line allocation plan to all of the earth stations, and the earth station transmits the divided plans obtained by dividing the line allocation plan to all of the earth stations, and the earth station uses the received data to transmitting a response to the reference station as to whether or not normal reception was achieved by performing error detection;
The line allocation plan delivery method is characterized in that the reference station receives the response and re-delivers only the divisional plan that has not been normally received to the earth station that has responded that normal reception has not been made.