JPH073971B2 - Signal transmission device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device for transmitting information such as a facsimile signal from a transmitting station to a plurality of receiving stations via lines.

2. Description of the Related Art In order to transmit a digital code to a receiving station without transmission error, an error control method for correcting transmission error is required.
ARQ (Automatic Repeat Request) is used as an error control method in data transmission.
uest)] method is widely used.

A signal transmission device using the conventional ARQ method will be described below with reference to FIG.

In FIG. 5, reference numeral 51 is a transmission device, 52 is a transmission control unit for transmitting a fixed amount of information in frames, and 53 is a response information receiving unit for receiving response information. 54 is a data line. 55, 59, 5D is a receiving device, 56, 5A, 5E is a reception control unit that receives a frame and determines that there is no transmission error, 57, 5B, 5F is information whether the frame is correctly received or not Is a response information transmitting unit for transmitting to the transmitting device 51 as response information, and 58, 5C, 5G are response information lines.

The operation of the above configuration will be described below. The transmission control unit 52 in the transmission device 51 divides the information into a certain number of pieces, various control information for each transmission unit, and an FCS [frame that is transmission error detection information that occurs on the transmission path.
Check Sequence)
A frame to which a code is added is formed and is sent to the data line 54 in frame units. Reception controller in the receiver 55
Each time 56 receives a frame, it performs a transmission error check using an FCS code. The reception control unit 56 notifies the response information transmission unit 57 of information as to whether there is a transmission error. The response information transmission unit 57 receives a normal reception response (hereinafter referred to as ACK) when a frame is received without a transmission error, and an abnormal reception response (hereinafter referred to as an ACK) when a received frame has a transmission error.
It is called NACK. ) Is sent to the response information line 58. Also in the other receiving devices 59, 5D, a transmission error check is performed on the received frame in each of the reception control units 5A, 5E,
The result is sent from the response information transmission units 5B and 5F to the response information line 5
It transmits to the transmitter 51 using C and 5G. Transmitter
When the response information receiving unit 53 in 51 does not receive the ACK, the transmission control unit sends a retransmission instruction from the corresponding frame.
Output to 52. The transmission control unit 52 retransmits the frame instructed to be retransmitted. With the above operation, it is possible to correct a transmission error that has occurred during transmission on the data line 54.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described configuration, in order to generally shorten the transmission time, the transmitting device 51, after completing the transmission of a certain frame, continues to receive the response information for the frame without receiving the next response information. ACK or NACK to send the frame
It is difficult to associate the transmitted frame with the response information only with the response information. Also, since the delay time from the transmission of a frame to the return of response information differs for each receiving device, after the completion of transmission of a certain frame, confirm that the frame has been received by all receiving devices without transmission error. Therefore, it is necessary to receive ACK three times. Therefore, there has been a problem that the retransmission management of the transmitting device becomes complicated as the number of receiving devices increases.

The present invention solves such a problem of the prior art, and aims to simplify transmission error correction control by frame retransmission even in a system with a large number of receiving devices by associating frames with response information. To do.

Means for Solving the Problems The present invention configures a transmission frame for transmission information at regular intervals, receives a transmission signal transmitted with a frame number, and transmits the transmission signal without transmission error. A plurality of receiving devices each having a discriminating means for discriminating whether or not it has been received, and a response information transmitting means for transmitting, as response information, the maximum frame number among the frame numbers of which the discrimination result is received without transmission error, A first transmission control unit that configures a transmission frame for information at regular intervals, assigns a frame number, and sends the transmission signal to a plurality of the receiving devices by broadcast communication. Responses in the plurality of receiving devices A plurality of response information transmitted from the information transmitting means is received, the response information is compared at regular intervals, the minimum value of the frame number is calculated, and the maximum response information is calculated. Response information minimum value calculating means to send as a small value, after transmitting the transmission signal to the plurality of receiving devices, to calculate the delay cycle time until the response information returns, from the delay cycle time of the response information A response information expected value calculation unit that calculates an expected arrival time, and a transmission error frame by the expected arrival time calculated by the response information expected value calculation unit and the response information minimum value calculated by the response information minimum value calculation unit. And a signal transmission device including a transmission device having a second transmission control unit for transmitting a predetermined frame again to the plurality of reception devices.

With the above configuration, the present invention associates the transmitted frame with the response information, and uses the minimum value of the frame number as the representative value of all the response information for the response information from the plurality of receiving apparatuses, thereby enabling the multiple receiving apparatus. On the other hand, in a system that broadcasts simultaneously, it is possible to easily control the correction of transmission errors due to retransmission.

Example Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a signal transmission device according to an embodiment of the present invention. In FIG. 1, 10 is a transmitter, and 11
Is a transmission control unit that performs frame transmission control, 12 is a response information expected value calculation unit that calculates an expected value of response information, 13 is a retransmission frame number calculation unit that calculates a frame number to be retransmitted, 14
Is a response information minimum value calculation unit, 15, 16 and 17 are response information reception units,
18 is a data line. 19,1D, 1H are receivers,
1A, 1E, 1I is a reception control unit for checking that the received frame has no transmission error, and 1B, 1F, 1J is response information for transmitting the frame number of the frame received without transmission error to the transmission device 10 as response information. The transmitters, 1C, 1G and 1K are response information lines.

The operation of the above configuration will be described below.
First, in the transmitter 10, the transmission control unit 11 separates information into fixed bits, adds various control information, and then adds an FCS code, which is a transmission error detection code, to form the frame shown in FIG. , To the data line 18. At this time, as the control information, a frame number that is incremented by 1 from n is given (n is an integer). The transmission control unit 11 notifies the response information expected value calculation unit 12 of the frame number being transmitted. The expected response information value calculation unit 12 calculates the time T at which the response information of the frame returns from the first equation from the current time t and the delay time D until the response information is returned from the receiving device that takes the longest transmission time, Make the one shown in FIG.

T = t + D + m (1) (where, m1 is a constant for absorbing the deviation of the delay time) On the other hand, the receiving device 19 receives the frame via the data line 18, and the receiving control unit Perform transmission error check using FCS code at 1A. The reception control unit 1A notifies the response information transmission unit 1B of the transmission error check result and the frame number.
The response information transmission unit 1B uses the frame shown in FIG. 4 as the received frame number, which is the maximum value of the series of frame numbers of the frames received without transmission error, and transmits the response information through the response information line 1C. And sends it to the transmitter 10.

Similarly, for the other receiving devices 1D and 1H, each receiving control unit 1E,
The transmission error check of the frame received by 1I is performed, and as a result, the response information transmission units 1F, 1J show the maximum value of the series of frame numbers received without transmission error as the received frame number and the frame shown in FIG. Is used as response information to be transmitted to the transmission device 10 via the response information lines 1G and 1K.

The transmission device 10, the response information received via the response information line 1C, performs a transmission error check using the FCS code in the response information receiving unit 17, the received frame number in the response information received without transmission error , And outputs the maximum value to the response information minimum value calculation unit 14.

The other response information receiving units 15 and 16 also perform a transmission error check on the response information received via the response information lines 1K and 1G, and the maximum value of the received frame number in the response information received without a transmission error. To the response information minimum value calculation unit 14. The response information minimum value calculation unit 14 includes each response information reception unit.
The received frame numbers output by 15, 16 and 17 are compared, and the minimum received frame number value MIN (t) is output to the retransmission frame number calculation unit 13. On the other hand, the response information expected value calculation unit 12
From the current time t and the table shown in FIG. 3, the received frame number expected to be received when there is no transmission error
EXPT (t) is calculated and output to the retransmission frame number calculation unit 13. The retransmission frame number calculation unit 13 uses MIN (t) and EXPT
(T) is compared, and if MIN (t) <EXPT (t), it is judged that a transmission error has occurred in frame number {MIN (t) +1}, and retransmission is performed from frame number {MIN (t) +1}. To the transmission control unit 11. The transmission control unit 11 sequentially retransmits the frames instructed to be retransmitted. After the retransmission frame number calculation unit 14 outputs the retransmission frame number, the retransmission frame number calculation unit 14 repeats retransmission until the frame number EXPT (t) output by the response information expectation value calculation unit 12 matches the frame number {MIN (t) +1} for which retransmission is instructed. The frame number output operation is not performed.

As is clear from the above description, by providing the response information minimum value calculation unit 14 and the response information expected value calculation unit 12 in the transmission device 10, it is possible to detect a transmission error in a system that transmits information to a plurality of receiving stations. Then, it becomes possible to easily perform error correction by retransmission.

In the present embodiment, the case where information is transmitted to three receiving devices has been described, but the present invention can be applied to the case where the number of receiving devices is n, which is larger than that.

EFFECTS OF THE INVENTION As described above, according to the present invention, when the transmission device is provided with the response information expected value calculation unit and the response information minimum value calculation unit, when information is simultaneously transmitted to a plurality of reception devices, a transmission error is detected. And correction by resending can be done easily. Further, when the number of receiving devices increases or decreases, only the response information minimum value calculation unit needs to be changed, and the system can be easily changed.

[Brief description of drawings]

FIG. 1 is a block connection diagram of a signal transmission device according to an embodiment of the present invention, FIG. 2 is a conceptual diagram of a transmission frame in the device, and FIG. 3 is a frame number by the device and a time when the response information is returned. FIG. 4 is a diagram showing a relationship, FIG. 4 is a configuration diagram of a response information frame by the device, and FIG. 5 is a block connection diagram of a conventional signal transmission device. 10 ... Transmission device, 11 ... Transmission control unit, 12 ... Response information expected value calculation unit, 13 ... Retransmission frame number calculation unit, 14 ... Response information minimum value calculation unit, 15, 16, 17 ... Response Information receiver, 18
...... Data line, 1C, 1G, 1K …… Response information line, 19,1
D, 1H …… Reception device, 1A, 1E, 1I …… Reception controller, 1B, 1F, 1J
...... Response information transmission unit.

Claims (1)

[Claims] 1. A transmission frame is formed with respect to transmission information at regular intervals, a transmission signal transmitted with a frame number is received, and it is determined whether or not the transmission signal is received without a transmission error. And a plurality of receiving devices each including a response information transmitting unit that transmits the maximum frame number as response information among the frame numbers that receive the determination result without any transmission error. A first transmission control unit that configures a transmission frame, assigns a frame number, and sends the transmission signal to the plurality of receiving devices by broadcast communication, and transmits the response information from the response information sending means in the plurality of receiving devices. Response information that receives multiple response information, compares the response information at regular intervals, calculates the minimum value of the frame number, and sends it as the minimum response information value. Minimum value calculation means, a response for calculating a delay cycle time from the transmission of the transmission signal to the plurality of receiving devices until the response information returns, and calculating an expected arrival time of the response information from the delay cycle time A transmission error frame is calculated based on the expected arrival time calculated by the information expected value calculation unit and the response information expected value calculation unit and the response information minimum value calculated by the response information minimum value calculation means, and the predetermined frame is again calculated. A signal transmission device comprising a transmission device having a second transmission control unit for transmitting a signal to a plurality of the reception devices.