SU1587645A1 - Method of transmission and reception of digital signals with correction of errors - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to extend the functionality by providing digital signals, encoded with correction codes shortened by an arbitrary number of elements of the signal, over the channels with "reverse operation". The insensitivity property of digital signals to "reverse operation" allows using this method of transmitting and receiving digital signals in channels with "reverse operation", for example, in channels with phase shift manipulation. In channels with relative phase manipulation, this method allows the use of " intrinsic " noise-tolerant coding, in which a digital signal represented in relative rather than absolute form is encoded and decoded. In the case of "external" coding for dealing with dual errors, the digital stream is divided into two sub-streams and two codecs are used. With the "internal" coding, the errors are independent, and it suffices to use one codec. 2 Il.

Description

The invention relates to radio engineering and technology of noise-resistant coding and can be used in systems for transmitting digital signals over channels with reverse operation.

The aim of the invention is to extend the functionality by providing the transmission of digital signals, encoded by correction codes shortened by an arbitrary number of elements of a signal, over channels with reverse operation.

FIG. 1 shows block diagrams of the transmitting and receiving parts of a system that implements a method for transmitting and receiving digital signals with error correction; figure 2 - temporary

Diagrams illustrating the implementation of this method of transmitting and receiving digital signals with error correction.

The transmitting part of the system implementing the method of transmitting and receiving digital signals with error correction contains an input random access memory (RAM) 1, an encoder 2 of an uncorrected Hamming code, an output RAM 3, a block 4 for controlling the operation of the RAM, and the receiving part is an input RAM 5, a decoder 6 unsharpened Hamming code, output RAM 7, block 8 of RAM control.

The method consists in transmitting each block consisting of a sequence (k-1) of information 2 D

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signal elements, each with a duration of t, are transformed in time in the AI into a block consisting of a sequence of 1 zero signal elements, (k-1) signal information elements, and (n - k) zero elements

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signal, each duration C -

encode with a correction code, replace- (nk) the last zero elements of B with the signal verification elements, B | Torically transform in time into a block consisting of consecutive (k-1) information elements of the signal and

l k-1 nala, each lasting (/ -,

Excluding the zero elements of the signal previously entered at block 1, V is transmitted over the communication channel. The reception of a digital signal is again converted in time into a block consisting of a sequence of n signal elements, input, 1 additional zero elements of the Signal at the same time positions in the transmission. Then digital

The signal is decoded with a correction error, after which it is transformed again (comfort in time, excluding 1 previously introduced additional zero elements of the ioB signal and (n-k) test elements of the signal.

: At the same time, as 1 additional signal elements for each block, not zero signal elements are used, but 1 signal element 4 of one of the previously transmitted 1 Example blocks of the previous one. Since these 45 additional signal elements are part of one of the previously transmitted blocks, they are transmitted over the communication channel almost simultaneously with the transmission of (k-1) information and (n-k) check elements of the signal. In this way, all the elements of each word signal are transmitted over the communication channel, albeit in two different blocks. In the case of channel B transition, the reverse operation mode 1 additional, (k-1) informational (n-k) test elements of the signal are replaced with opposite ones, i.e. the entire codeword is inverted. If the correction code is insensitive to reverse operation, the inverted code word will be decoded correctly regardless of the values. Investigator

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but, when using this method, the insensitivity property to reverse operation is retained.

As an example, consider the transmission and reception of digital signals encoded by the Hamming code (31.26, 3), insensitive to reverse operation. For practical use, it is more convenient to use a digital signal consisting of blocks with a length of 30 rather than 3, i.e. coded with a shortened code (30,25,3).

The sequence consisting of the 25th information element of the signal of the previous block and 25 information elements of the signal of this block is recorded sequentially in 1-26 memory cells of RAM 1, and zero cells of the signal are recorded in memory cells 27-31. Then, sequential readings of signal elements from memory cells 1-31 of RAM 1 are performed. Then encoder 2 calculates five check signal elements and enters them at time positions 27-31, and writes them in memory cells 1-31 RAM 3 all 31 elements of the sequence signal from the output of encoder 2, and then sequentially read 30 signal elements from memory cells 2-31 to the communication channel. The control unit 4 controls the operation of the RAM 1 and 3 for writing and reading.

The 25th signal element from the previous block and 30 signal elements of this block, received from the communication channel, are recorded sequentially in 1-31 memory cells of RAM 5, and then sequentially read the signal elements from memory cells 1-31 of RAM 5. The decoder 6 corrects in the digital signal the error, and then the signal elements are written in the same sequence in cells 1-31 of RAM 7. After that, 25 signal elements are sequentially read from memory cells 2-26 of RAM 4. Control unit 8 em work RAM 5 and 6 to write and read .

The insensitivity property of digital signals to reverse operation allows using this method of transmitting and receiving digital signals in channels with reverse operation, for example, in channels with phase shift.

In channels with relative phase shift manipulation, this method allows the use of internal error-correcting coding, in which a digital signal presented in relative rather than absolute form is encoded and decoded.

For external coding, for dealing with dual errors, the digital stream is divided into two sub-streams and two codecs are used, and for internal coding, errors are independent and it is sufficient to use one codec.

Claims (1)

Invention Formula A method of transmitting and receiving digital signals with error correction, comprising the fact that every (k-1) information elements of a digital the body () transforms in time the time ;; ovality consisting of (k-1) information elements, 1 additional elements, and (n-k) test elements duration k-1 С - each, by (n-k) -checking the elements according to the rules for checking the JO JOKING (PD) code defined and correct the erroneously received information elements, from the corrected sequence on a variable interval T (k-1) form 15 (k-1) information elements for each C, different in that, in order to extend the functionality of the transmission and reception a signal corresponding to a shortened 20 digital signals encoded corrective code on the time interval -C (k-l), where C is the duration of each information element, k is the number of information element-shortening codes with an arbitrary degree of shortening 1, through channels with reverse operation, on the transmitting side Comrade selected corrective (n, k) - 25 and s (k-1) information elements code with the total number of characters n, is converted in time into a sequence consisting of (k-1) information elements, 1 additional elements and (n-k) zero elements k-1 duration - each, and from (k-1) information elements, and 1 additional elements at the temporary positions (nk) of the zero elements form (nk) check elements of the selected corrective (n, k) code and transmit the generated sequence via the communication channel, and received side 35 40 1 information elements are selected and stored, which use as 1 additional elements when transforming in time into one. of the following sequences from (k-1) information elements, and on the receiving side, in each received sequence, 1 corresponding information elements are stored and memorized, which are used as 1 additional elements when transforming in the subsequent received arguments from (kl) information elements. body () is transformed in time into the last ;; ovality, consisting of (k-1) information elements, 1 additional elements and (n-k) test elements of duration k-1 С - each, by (n-k) -checking the elements according to the rules for checking the cor-O of the Protecting (PD) code are determined and correct erroneously received information elements, from the corrected sequence on the time interval T (k-1) 5 (k-1) information elements of duration C each are formed, characterized in that, in order to extend the functionality by providing transmission and reception shortened codes with an arbitrary degree of shortening 1, on channels with reverse operation, on the transmitting side in each sequence and s (k-1) information elements 1 information elements are selected and stored, which are used as 1 additional elements when transforming in time in one of the subsequent sequences of (k-1) information elements, and on the receiving side in each received sequence 1 corresponding information elements, which are used as 1 additional elements when transforming in time in subsequent received sequences from (kl) information elements. Broadcast. Reception 3.2