JPH06101686B2 - Majority decoding device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a majority decoding device in data communication, particularly in data communication of a line in which both random error and burst error frequently occur.

(Prior Art) FIG. 5 is a diagram showing a data communication system using a conventional majority encoding / decoding method. In the figure, 51 is a data transmitter, 52 is an encoder, 53 is a communication channel, 54 is a decoder,
55 is a data receiver. In this conventional data communication system, the data input from the data transmitter 51 to the encoder 52 is encoded by an error detection code, and the encoded data is transmitted to the communication path 53 a plurality of times as one frame. It The decoder 54 stores the received data of a plurality of frames and takes the majority of the bits corresponding to the data of the plurality of frames. The result of the majority decision is taken as one frame and is decoded with an error detection code. Therefore, errors can be reduced.

(Problems to be Solved by the Invention) However, although the conventional method can deal with a random error with relatively few errors, when data communication is performed in a mobile body such as an automobile, fading occurs as the mobile body travels. If more than half of the frames are erroneous due to the long burst error caused by the occurrence of the error, even if there are correctly received frames, the majority decision results in decoding into erroneous data. Therefore, if the data is incorrect, a retransmission request is issued by an appropriate means and the data is retransmitted, so that there is a problem that the transmission efficiency of the communication path is reduced.

The present invention is intended to solve these problems, and an object of the present invention is to provide a majority decoding apparatus having excellent performance against both random errors and burst errors.

(Means for Solving Problems) In order to solve the above problems, the present invention uses the same coding unit for coding transmission data of a constant length with an error detection code and the same coded data as one frame. First error detection means for decoding the data sent from the transmission side, which has a transmission means for transmitting a plurality of frames of transmission data, with an error detection code for each frame, and detecting the presence or absence of an error Decoding means for decoding a plurality of frames of the transmission data of 1 by majority to form one frame, and second error detecting means for decoding the frame after the majority decoding with an error detection code to detect the presence or absence of an error, Result of error detection for each frame by the first error detecting unit When no error is detected in any frame, the frame in which the error is not detected is regarded as valid data and output. When an error is detected in all the frames by the first error detecting means, the corresponding frames are decoded by the decoding means by the majority decision, and the frames after the majority decision decoding are output by the second decision. The error detection means detects an error with the error detection code, and if the error is not detected, the frame after the majority decoding is regarded as valid data and is output from the output terminal. There are features.

(Operation) According to the present invention having the above-described configuration, when the error is not detected in any of the frames as a result of the detection by the first error detecting unit, the error is not detected by the instruction of the control unit. The frame is regarded as valid data and is output from the output terminal. When an error is detected in all the frames by the first error detecting means, the corresponding frames are decoded by the decoding means by the majority decision, and the frames after the majority decision decoding are made by the second error detecting means. An error is detected by the error detecting code, and if no error is detected, the frame after the majority decoding is regarded as valid data by the instruction of the control means and is output from the output terminal.

Therefore, the present invention can solve the above-mentioned problems and can provide a majority decoding apparatus capable of performing excellent data communication with respect to both random errors and burst errors.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an encoder applicable to the present invention, and FIG. 2 is a block diagram showing a decoder according to an embodiment of the present invention. In FIG. 1, 11 is an encoder input terminal, 12 is a transmission data storage device that stores transmission data, 13 is an error detection encoder that generates an error detection code, and 14
Is a storage device that stores the error detection code created by the error detection encoder 13, 15 is a switch that switches between transmission data and the error detection code, 16 is a control unit, and 17 is an encoder output terminal. In FIG. 2, reference numeral 21 denotes a decoder input terminal, 22-
, 22-n is a received data storage device for storing each frame of received data, 23 is a majority logic element, 24 is a storage device for storing data after majority decoding, and 25 is an error detection code. Error detector / decoder that performs the check of the received data, 26 is a switch for switching the reception data storage device, 27 is the error detection decoder
Is a switch for switching the input to the switch, 28 is a switch for switching the output of the decoded data, 29 is a control unit, and 30 is a decoder output terminal.

Next, the operation of this embodiment will be described with reference to FIGS. 1 and 2.

First, the operation of the encoder of FIG. 1 will be described. First, the data input to the encoder from the input terminal 11 is stored in the transmission data storage device 12 and simultaneously input to the error detection encoder 13. To be done. The generated error detecting code is stored in the storage device 14. The stored data and error detection code are framed in the format shown in FIG. 3 according to an instruction from the control unit 16 and output from the output terminal 17. In FIG. 3, 31-1, 31-2, ..., 31-n are the first, second, ..., Nth frames, and 31-1-1, 31-2-1 ,. n-
1 is transmission data, 31-1-2, 31-2-2, ..., 31-n-2
Is an error detection code.

Then, the operation of the decoder of FIG. 2 is performed as follows. First, the reception data input from the input terminal 21 to the decoder is stored in the reception data storage devices 22-1 to 22-n, and at the same time, input to the error detection decoder 25 to decode the error detection code. Is performed and checked for errors.
The presence or absence of an error is input to the control unit 29, and when the error is not detected in any frame, the switch 28 is instructed by the control unit 29 to store the frame in which the error is not detected. By switching to the output terminals 1 to 22-n, the reception data stored in the connected reception data storage device is output from the output terminal 30 as valid data.

On the other hand, when an error is detected in all the frames, the data of all the received frames are input to the majority logic element 23, the majority of the corresponding data is performed, and the result after the majority decision is stored in the storage device 24. At the same time, it is input to the error detection decoder 25, and the presence or absence of an error is checked. If no error is detected, the switch 28 is connected to the storage device 24, and is output to the output terminal 30 as valid data according to an instruction from the control unit 29. Received data storage device if an error is detected
The data stored in the storage devices 22-1 to 22-n and the storage device 24 are discarded.

Further, in order to further improve the error improving effect by using the majority decoding apparatus of the present invention, the encoder side does not collectively send the same type of frames as one block but different types. These frames are combined and sent as a block. Use of this coding method is effective for long bursts. FIG. 4 shows a block diagram of the frame. 41, 42, ..., 49 represent each frame. Each of the frames 41 to 43, the frames 44 to 46, and the frames 47 to 49 is regarded as one block. A, B, C indicate each type. Due to the long burst error, no error occurs in frames 44-49 even if frames 41-43 are incorrect.

(Effects of the Invention) As described above, according to the present invention, of the fading of the frequency that occurs in proportion to the speed of the moving body, when the fading of the low frequency is performed, the burst error and the fading of the high frequency are performed. Even if a random error occurs, a long burst and a long error-free section are alternately present in a burst error. Therefore, even if a majority of the frames are erroneous due to the burst error, even one frame has no error. If so, valid data can be obtained. Also, if there is a random error, there is a small number of errors in all frames, and the probability that an error occurs at the same bit position in each frame is low. In most cases, the majority code eliminates the error and obtains valid data. be able to.

Therefore, according to the present invention, it is possible to realize data communication that is robust against both random errors and burst errors.

[Brief description of drawings]

FIG. 1 is a block diagram showing an encoder applicable to the present invention, FIG. 2 is a block diagram showing a decoder according to an embodiment of the present invention, and FIG. 3 is an encoded signal applicable to the present invention. FIG. 4 is a block diagram of a coded signal applied to the present invention, and FIG. 5 is a block diagram showing a data communication system based on a conventional majority coding / decoding system. . 11 …… Encoder input terminal, 12 …… Transmission data storage device, 13 …… Error detection encoder, 14,24 …… Storage device, 15,26,27,28 …… Switch, 16,29 …… Control unit, 17 ... Encoder output terminal, 21 ... Decoder input terminal, 22-1 to 22-n ... Received data storage device, 23 ... Majority logic element, 25 ... Error detection decoder , 30 …… Decoder output terminal.

Claims (1)

[Claims] 1. A transmission side having encoding means for encoding transmission data of a fixed length with an error detection code, and transmission means for transmitting a plurality of frames of the same transmission data with the encoded data as one frame. The first error detecting means for decoding the data sent from the device with an error detection code for each frame to detect the presence or absence of an error, and the plurality of frames of the same received transmission data received by majority decoding to form one frame. Decoding means for decoding the frame after majority voting with an error detection code to detect the presence or absence of an error; and an error detection result for each frame by the first error detecting means. If no error is detected in the frame, the frame in which the error is not detected is regarded as valid data and is output from the output terminal. Ri when an error is detected in every frame, corresponding with the decoding means in frame to each other is decoded by majority, the frame after the majority decoding second
Error detection means to detect an error with the error detection code,
A majority decoding apparatus, comprising: a control unit that, when no error is detected, regards the frame after the majority decoding as valid data and outputs it from an output terminal.