JP2604784B2 - Meeting line communication method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an improvement in a communication method of a burst for a meeting line (hereinafter, abbreviated as an OW burst) in time division multiple access (TDMA) communication, and in particular, per frame. The present invention relates to an efficient meeting line communication system using one meeting line burst.

[Conventional technology]

Conventionally, in this type of meeting line communication system, as shown in FIG. 5, communication is performed sequentially using one OW burst per frame. That is, the station A first transmits the OW burst (A) continuously for each frame, and sends its own message.
Next, station A stops transmitting the OW burst, and station B then sends its message in the same way as station A, that is, station B
The OW burst (B) is transmitted continuously for each frame. Thus, each station communicated with the OW burst occupied by each station. When station A transmits again, the above operation is repeated.
That is, the station A transmits the OW burst after the station B stops the OW burst. Thus, each station communicated in turn.

FIG. 3 is a block diagram showing a configuration of a conventional meeting line communication system, and FIG. 4 is a timing chart of signals of respective parts in FIG. This configuration has a write counter 11 for writing OW data, a read counter 12 for reading written OW data, a 1/2 counter 13 for alternately switching between writing and reading for each frame, and an inverting gate 14. , Selectors 15 and 16, memories (usually RAMs) 17 and 18, and an OR gate 19.

The operation will be described with reference to FIGS. Conventionally, one station monopolizes the OW burst and transmits every frame, so it suffices to receive the OW burst every frame. In order to convert the burst data OWBST into continuous data OW DATA, a double buffer system as shown in FIG. 3 is used. It has two buffers, that is, two memories 17 and 18. When data is written in one memory, the operation of reading data from the other memory is performed alternately. In other words, data is always written to one of the memories, and the already written data is always read from the remaining memories. For example, OW BST, which is data already written to memory 17, is OW DAT, which is continuous data.
When the data is read as A, the OW BST, which is the write data at that time, is written to the metadata 18, and when the written data is subsequently read as OW DATA from the memory 18, the memory 17 The OW BST at that time has been written. In order to perform this for each switching frame, a 1/2 counter 13
The selectors 15 and 16 are switched by the output obtained by dividing the frame pulse signal FR PLS by 2, and the memories 17 and 18 are alternately set to the write / read mode. In this manner, as shown in FIG. 4, OW BST, which is high-speed burst data, is converted into OW DATA, which is low-speed continuous data, every frame.

[Problems to be solved by the invention]

In the conventional meeting line communication system described above, only one OW burst is transmitted per frame, that is, one-way communication is performed. In addition, since it is not a two-way communication, the operation is very troublesome in operation, and there is a drawback that it is difficult to make an immediate meeting using a meeting line.

In order to solve this problem, it is easy to find out that two OW bursts should be output in one frame so that each station can transmit them. However, it is not always used. It is inevitable that the frame efficiency is deteriorated because of the meeting line. That is, the OW burst must be transmitted one extra burst. This is due to OW bursts that are not normally used and should be avoided as much as possible.

[Means and actions for solving the problem]

In order to solve the above problems, in the meeting line communication system of the present invention, in a meeting line communication system in which a meeting is made between any two of a plurality of stations constituting a TDMA communication system, each of the two stations , A frame number counter that counts the number of received TDMA frames, and the received TDMA
It has two sets of memories for describing a burst for a meeting line (hereinafter abbreviated as an OW burst) included once in two frames in a specific time slot in a frame, and each time the frame number counter counts two frames, The received OW burst is written into one of the two sets of memories, and the read operation is switched from the other to convert the received OW burst into continuous received data. Each of the two stations converts the OW burst to be transmitted into two frames into two frames. By transmitting the received OW burst once so as not to alternately overlap with the same time slot as the received burst on the frame where there is no existing OW burst, one OW burst is used for one frame, and the time slot of the OW burst is used. It is characterized in that communication between the two stations can be performed without being fixedly assigned to the stations.

Since the number of bursts is one, the above solution is 1
For the method of transmitting two bursts to a frame, the frame efficiency is improved by the amount of the prefix code provided at the head of each burst. Note that the prefix code includes a carrier wave reproduction code, a clock reproduction code, a unique word code, and the like, which are necessary only for receiving, reproducing, and demodulating a burst signal.

〔Example〕

FIG. 1 is a block diagram showing a configuration of a meeting line communication system showing one embodiment of the present invention, and FIG. 2 is a timing chart showing the operation of FIG. This configuration includes a write counter for writing OW data, a read counter for reading OW data that has already been written, and a frame number counter (hereinafter, FR) for counting frames for switching between writing and reading. No. counter) 3, inverting gate 4, selectors 5, 6, memories 7, 8, and OR gate 9.

The fundamental difference between the conventional example shown in FIG. 3 and the present invention is that the transmission method of the OW burst is every frame or every two frames, and the writing and reading cycles to and from the memory change accordingly. . Note that the length and cycle of the OW GATE for memory writing also change. That is, as shown in FIG. 2, the write and read cycles are two frames. OW in Fig. 1
The length and period of GATE1 are twice as long as OW GATE2 in FIG. Therefore, the capacity of the memories 7 and 8 is
18 times each.

Next, the operation will be described in detail. In FIG. 1, FR N
o. The counter 3 counts the input frame pulse FR PLS and switches the write or read cycle of the memories 7 and 8 with the selectors 5 and 6 as two frames. At the same time, when, for example, the memory 8 is set to the write mode by the inversion gate 4, the memory 7 is set to the reverse read mode, and the memories 7 and 8 are always in the write / read mode or the read / write mode.
The mode is switched so as to be a pair of the write modes. First, when the output of the FR No. counter 3 becomes high level and the memory 8 is in the write mode, the write counter 1 is supplied to the memory 8 by the receiving clock RX CLK only during the OW GATE corresponding to the OW BST to be received by the own station. Operates and the data of that OW BST is written.

Next, the output of FR No. counter 3 goes low,
When the memory 8 is in the read mode, the read counter 2 is read by the continuous meeting line clock OW CLK for read.
Operates, the already written data is read, and continuous data OW DATA is output as shown in FIG. 2 (e). Is inverted by the inverting gate 4, so that the operation completely opposite to that of the memory 8 is performed.
That is, as shown in FIGS. 2 (f) and 2 (g), the mode of writing and reading is alternately switched by the output of the FR No. counter of FIG. 2 (b).

By the way, OW GATE 1 is, as shown in FIG.
It is input once per frame at the timing to be received, and its length is the number of bits corresponding to two frames. Therefore, the OW BST is written to the memory once every two frames, and the reading is also performed for two frames. It is performed continuously for a while, but there is no excess or deficiency of OW data, and communication is performed correctly.

In this manner, one OW burst is alternately transmitted by two stations every other frame, so that one OW burst is transmitted once per frame.
Two-way communication is possible even with OW burst.

In the embodiment, the communication between two stations has been described. However, it can be easily extended by analogy that the communication can be performed by one OW burst between a plurality of stations of three or more stations in a similar manner.

〔The invention's effect〕

As described above, according to the present invention, OW bursts are
By alternately transmitting one frame at a time, two-way communication can be performed as if there were two OW bursts, despite one OW burst per frame.
There is an effect that the meeting can be performed smoothly.

Also, there is an effect that the frame efficiency can be improved as compared with the case where two OW bursts are output in one frame.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a meeting circuit communication system according to one embodiment of the present invention, FIG. 2 is a time chart of signals of respective parts for explaining the operation of FIG. 1, and FIG. FIG. 4 is a block diagram showing a configuration of a communication system, FIG. 4 is a time chart of signals of respective parts for explaining the operation of FIG. 3, and FIG. 5 is a time chart for explaining a conventional communication system. In the figure, FR PLS: frame pulse, RX CL
K: Receiver clock, OW CLK: Meeting line clock.

Claims (1)

(57) [Claims] 1. A meeting line communication system for making a meeting between any two stations in a plurality of stations constituting a TDMA communication system, wherein each of the two stations counts the number of received TDMA frames, and It has two sets of memories for storing a burst for a consultation line (hereinafter abbreviated as an OW burst) included once in two frames in a specific time slot in a received TDMA frame, and the frame number counter counts two frames Each time the OW burst is to be transmitted, the received OW burst is written into one of the two sets of memories, and the read operation is switched from the other to convert the received OW burst into continuous received data. Once every two frames, in the same time slot as the received burst on the frame where the received OWT burst does not exist Re by transmitting so as not to overlap each other, 1 using one OW bursts in the frame, without assigning fixedly to the station time slots OW burst,
A meeting line communication system, wherein communication between the two stations is enabled.