JPH01149640A - Loop type data transmitting system - Google Patents

Abstract

PURPOSE:To make transmission of a response signal against a series of message transmission one time only so as to make the time required for carrying out entire transmission shorter by continuously making message transmission by means of concatenated frames and, at the same time, causing a receiving station to transmit the response signal after the station receives a series of frames. CONSTITUTION:From transmitting station SS a message D is transmitted in such a way that the message D is divided and concatenated to fixed-length frames with numbers and continuously transmitted by using the frames. At the time of completing the transmission of the message D, The station SS transmits a response requesting signal RQ. Upon receiving the response requesting signal RQ after receiving all of the concatenated frames, a receiving station SR transmits a response signal RS containing the number of a frame, to which a resending request is to be made. A synchronizing pit S, destination address DA, and transmitting source address SA are allocated to each of a message frame A, response requesting frame B, and response frame C in the initial state. In the message frame A is followed by a frame number SN and message words I of a fixed length. In the response requesting frame B a response requesting flag RQ is allocated to the last and in the response frame C numbers SN1-SNn of frame which are requested to be re-sent follow.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a loop-type data transmission system for transmitting variable-length messages divided into fixed-length frames via a loop-shaped transmission line.

[Conventional technology]

In a data transmission method using a loop-shaped transmission path,
Divide variable length messages into fixed length frames,
While the transmitting station transmits a certain number of frames, the receiving station that receives this sends a response signal in response to receiving a certain number of frames, and requests retransmission of the same frame if necessary. If the response signal indicates a retransmission request, the transmitting station retransmits the requested frame.

FIG. 5 is a sequence diagram showing this situation. When the transmitting station SS transmits a message D divided into frames of fixed length by a fixed number of n frames, the receiving station SR receives a response signal. After transmitting signal A, upon reception of signal A, transmitting station SS transmits the next message or retransmission message every n frames, and repeats the above transmission and reception.

[Problem that the invention seeks to solve]

However, in the above-mentioned method, confirmation using the response signal A is performed every time the message D of n frames is transmitted, and the transmission time Tl for all messages includes the time for transmitting the response signal multiple times. , a problem arises in that it generally takes a long time to transmit all messages.

[Means for solving problems]

In order to solve the above-mentioned problem, the present invention is constructed by the following means.

In other words, in the loop data transmission method described above, the transmitting station concatenates message transmissions and sequentially sends messages to each numbered frame, and the receiving station retransmits the concatenated frames after receiving them. A response signal containing the number of the frame requesting the request is transmitted.

[Effect]

Therefore, messages are transmitted in consecutive frames, and the receiving station transmits a response signal after receiving a series of frames. Since the message is transmitted only once, the overall transmission time is shortened, and
Since the response signal includes the number of the frame that requires retransmission, there is no problem in the transmitting station retransmitting frames that have been lost in reception at the receiving station.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to figures showing examples.

FIG. 1 is a sequence diagram showing the transmission situation. From the transmitting station SS, a message D divided into fixed-length frames is sent.
are concatenated and sequentially transmitted in a numbered frame, and finally a response request signal RQ is transmitted, while in the receiving 4SR, the response request signal RQ is received after receiving all the concatenated frames. Then, in response to this, a response signal R8 containing the number of the frame requesting retransmission is transmitted.However, since the response signal R8 is transmitted only once for all message transmissions, the response signal R8 is transmitted only once for all message transmissions. Even including the transmission of the request signal RQ, the total transmission time T is significantly reduced compared to that in FIG.

FIG. 2 is a diagram showing the structure of each frame. In each of υ, the message frame (4), the response request frame ω), and the response frame C), a synchronization bit S is placed first, and then the destination The address DA and the source address 8A are arranged. In (4), for example, a frame number SN that is added consecutively by serial number, and a message word of a certain length are followed, and in @), at the end, A response request flag RQ is placed, followed by frame numbers 5NI-8Nn requesting retransmission in (C).

Figure 3 is a block diagram of the transmitting station SS, and Figure 4 is the receiving station SR.
In FIG. 3, a reception interface (hereinafter referred to as RIF) 2 and a synchronization circuit (hereinafter referred to as 5YC) are installed between the transmission line IR on the reception side and the transmission line 1S on the transmission side.
3. A frame creation circuit (hereinafter referred to as FRM) 4 and a transmission interface (hereinafter referred to as 5IF) 5 are inserted, and when the response frame shown in FIG. 2(C) arrives from transmission path 1R, it is received by RIF2.5YC3. Based on the output, a frame number determination circuit (hereinafter referred to as FNJ) 6 determines the number SNz"-SNH of the frame requesting retransmission, and provides it to a retransmission control circuit (hereinafter referred to as R2O) 7, which is used to control the terminal equipment. The transmitted message SI is stored in the transmitted data memory (hereinafter referred to as SDM) 8, and
In RM4, it is sequentially divided and inserted into fixed-length frames based on the synchronization signal from SYC3, and F
RM4 creates the message frame shown in Figure 2 (4),
5IF5 to the transmission line 1S.

At this time, the FRM 4 determines the frame number SN in a condyle shape and adds it to each frame.Finally, the FRM 4 creates the response request frame shown in Figure 2 (B) and transmits it in the same way. do.

Furthermore, when a response frame is received after the transmission of the message frame and response request frame is completed, the R8C7
causes the corresponding message to be sent from 80M8 to FRM4, a frame with the requested number is created again by FRM4 and retransmitted via SIF5.

On the other hand, in FIG. 4, in addition to providing RIF2 to FNJ6, which are the same as in FIG.
, and a retransmission request circuit (hereinafter referred to as R2H) 11 are provided, and each frame arriving from the transmission path 1R is RIF2.5
The message word (2) received by YC3) and received by Tore is sequentially stored in the address corresponding to the frame number from pFNJ6 by RDM9, and then sent to the terminal device as a received message RI.

The reception output of 8YC3 is also given to RFMlo, and every time a message frame is received normally, F
RFMlo sets a reception flag corresponding to the frame number from NJ6, and resets the flag if reception is abnormal, so the flag in RFM10 indicates the reception status of each message frame. There is.

When reception of the message frame is completed as described above and a response request frame is then received, R8R11 responds to this by giving the FRM4 a frame number that requires retransmission based on the contents of RFMlo. ) and create a response frame for S.

Send via IF5.

Then, in response to receiving the response frame, the transmitting station SS
In order to retransmit the frame with the requested number as described above, this will be received by RIF2 and 5YC3 in Figure 4, and if this is normal, the message will be stored in the corresponding address of RDM9 according to the output of FNJ6. be done.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a transmitting station transmits a message using concatenated and numbered frames, and a receiving station sends a frame requesting retransmission after receiving the concatenated frames. By transmitting a response signal that includes the number of the message, the number of times the response signal is transmitted is reduced to one time, which reduces the overall message transmission time, achieves high-speed transmission, and improves transmission efficiency. As a result, a remarkable effect can be obtained in loop-type data transmission.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention, FIG. 1 is a sequence diagram showing the transmission situation, FIG. 2 is a diagram showing the structure of each frame, FIG. 3 is a block diagram of the transmitting station, and FIG. FIG. 4 is a block diagram of a receiving station, and FIG. 5 is a sequence diagram showing a transmission situation in a conventional example. IB, 1B...Transmission path, 2...Reception interface, 3...Synchronization circuit, 4--Frame creation circuit, 5--...Transmission interface, 6...Frame number Judgment circuit, 7...Retransmission control circuit, 8...
...Transmission data memory, 9...Reception data memory,
10--Φ Receive flag memory, 11... Retransmission request circuit, SS... Transmitting station, SR... Receiving station, D...
...Message, RQ...Response request signal, R81
11111@Response signal, SN w SNI ~SNn
"1"・Frame number.

Claims (1)

[Claims] A transmitting station transmits a variable-length message divided into fixed-length frames via a loop-shaped transmission path, receives a response signal from a receiving station on the other side, and retransmits the frame requested to be retransmitted by the response signal. In the loop data transmission method performed from the transmitting station, the transmitting station continuously transmits messages using the frames, each of which is numbered, and the receiving station retransmits the messages after completing the reception of the concatenated frames. A loop data transmission method characterized in that the response signal including the number of the requested frame is transmitted.