RU2720901C1 - Method for noise-protected transmission of telemetric data with adaptation to communication channel state - Google Patents

Abstract

FIELD: computer equipment.

SUBSTANCE: method of transmitting digital information with adaptive selection of parameters of an interference-protected code, which is based on the principle that if the communication channel state does not enable to transmit data with the required level of reliability, then in that case a certain number of high-order bits is selected for transmission, wherein remaining part of least significant bits is arranged in organized in form of stack with limited volume "deferred buffer", wherein in the case of improving the communication channel state, a decision is made to transmit data stored in the buffer together with data coming from the data source, and the system itself operates in a continuous mode until all current and buffered data are transmitted.

EFFECT: technical result consists in improvement of reliability of data transmission.

1 cl, 1 dwg

Description

The invention relates to the field of encoding, decoding and adaptive transmission of digital information and can be used in telemetry systems.

There is a method of transmitting digital information with an adaptive choice of parameters of an anti-interference code, which is based on the principle that if the state of the communication channel does not allow data to be transmitted with the required level of confidence, then in this case a certain number of high-order bits are selected, and the remaining some of the younger ones are placed in the “remainder buffer” organized as an array. In the case of improving the state of the communication channel and after completion of the transmission of relevant data, a certain number of cycles are allocated for data transmission from the remainder buffer, and if the contents of the buffer cannot be transferred for a fixed number of system transmit / receive cycles, then it is forcibly cleared (Kupriyanova, O.V. Modeling of data transmission systems with adaptation to the state of the communication channel / OV Kupriyanova, A. V. Levenets, Yong Un Che // Scientific Bulletin of NSTU. - 2016. - No. 1. - P. 120-132).

The disadvantage of this method is that it does not guarantee the possibility of a complete data transfer.

The closest analogue of the claimed invention is a method of transmitting information using adaptive noise-resistant coding with quality control of the communication channel, the results of which are selected noise-resistant cascading code with variable parameters, which on the transmitting side encode the original information. Further, information protected by an error-correcting cascade code is transmitted to the communication channel, after which it is decoded on the receiving side to detect and correct errors, depending on the correcting ability of the selected code. According to the results of decoding the words of the internal code of the noise-tolerant cascade code, the quality of the communication channel is monitored, and the number of received and erased words of its internal code is determined with the number of transformed words of the internal code of the noise-resistant cascade code. After that, determine the minimum code distance of the external code of the error-correcting cascading code necessary for its correct reception. Next, the variable parameters of the noise-free cascading code are selected that provide the required minimum code distance for the code, then its variable parameters are determined taking into account their current rating and the previous rating obtained when receiving previously transmitted cascade codes, then these parameters are reported to the transmitting side (RF patent No. 2321180 H04L 1/20 (2006.01) dated 06/26/2006).

The disadvantage of this method is the lack of the possibility of partial data transfer on each cycle of reception / transmission of the system.

The technical problem to be solved by the claimed invention is directed is to increase the reliability of data transmission.

The problem is achieved by the fact that in the method of transmitting digital information with an adaptive choice of parameters of an anti-interference code, which is based on the principle that if the state of the communication channel does not allow data to be transmitted with the required level of reliability, then in this case some the number of high-order bits, and the remaining low-order bits according to the invention are placed in a stacked buffer with a limited amount, and in case of improvement of the state of the communication channel, a decision is made to transfer the data stored in the buffer together with the data received from data source, and the system itself operates in continuous mode until all relevant and placed in the buffer data is transferred.

The principle of operation of the invention is illustrated in the drawing, where in FIG. 1 shows a generalized structural diagram of a transmission / reception system.

The process of the system can be described as follows. From the data source (ID), the data is transmitted to the encoder (K), which implements their noise-free encoding using some algorithm and passes it further to the communication channel (CS), which is noisy by the noise generator (GP). The decoder (DC) decodes the received encoded sequence and transmits it to the data receiver (PD), after which, based on the selected method for assessing the state of the communication channel by the code corrector (QC), a decision is made to change the code parameters, followed by the transmission of the control action through the feedback channel (CBS).

If the state of the CS does not allow data to be transmitted with the required level of reliability, then in this case the data shaper (PD) selects a certain number of high-order bits for transmission, and the remaining part of the low-order bits is placed in a stack with a limited amount of “deferred buffer” data (DB) . In case of improvement of the state of the communication channel of the PD, a decision is made to transfer the data stored in the database, together with the data coming from the ID.

The following methods are used to assess the status of the communication channel: based on a direct assessment of the status of the communication channel; based on the evaluation of the decoding results of the noise-immune code and based on the calculation of the syndrome of the BCH code.

The first method is based on a direct assessment of the state of the communication channel and assumes that data with a predetermined structure (reference data) will be transmitted at a given frequency, while their bit depth should be equal to the channel capacity. In this case, the estimate expressed by the number of distorted bits is calculated by comparing the distorted reference data that passed through the communication channel with the undistorted ones.

The second method is based on the evaluation of the decoding result of the BCH code passed through the communication channel obtained for the reference data. It is important to consider that their bit depth is taken equal to the number of encoded bits of the code used. In this case, the estimate is generated by comparing the decoded distorted data that passed through the communication channel with the undistorted ones and determining the number of bits that have changed. This approach allows you to more efficiently use the bandwidth of the communication channel, but at the same time gives less reliable information about its state.

The third method is based on the calculation of the syndrome of the BCH code for the data encoded by it, the bit depth of which is similar to the bit depth of the reference data adopted for the second method. With this assessment, if the calculated syndrome is not equal to zero, then it is assumed that the data is distorted, otherwise it is argued that the data was transmitted without distortion. For this method, there is no need for the transfer of reference data, and therefore, the assessment can be carried out during the normal operation of the system and with the most rational loading of the communication channel, which occurs due to the greatest damage to its accuracy.

In order to ensure a given level of reliability of data transmission by the system, their noise-coding is carried out. As a base, it is proposed to use the algorithm for constructing the Bose-Chowdhury-Hockingham codes (BCH). The main parameters of the code are set by the generating polynomial, for the construction of which it is necessary to know the length of the code n and its correcting ability t, while the complete table of parameters of the BCH codes for a given degree of the polynomial in its original form is unsuitable for use due to its high redundancy. In this regard, in order to optimally use the bandwidth of the communication channel, it is necessary to carry out the process of removing unnecessary entries from it.

So, all records are deleted from the table, the code length of which is greater than the bandwidth of the communication channel, then they are sequentially sorted by increasing the correcting ability of the codes, the number of encoded bits and the length of the code. Further, for each unique value of the correcting ability of the code represented by more than one record from the table, records are deleted whose number of encoded bits is less than the bit depth, and among the remaining ones, all records are deleted except those that have the maximum number of encoded bits. After the manipulations have been done, each record, starting with the last, is checked for the condition that its code length should be greater than the code length of the record located above and if this condition is not met, then such records are deleted.

To implement adaptation to the actual state of the communication channel by selecting the optimal parameters of the noise-protected BCH code in accordance with the selected method for evaluating its state, it is proposed to use the following algorithms.

So, if you use a method based on evaluating the results of decoding an interference-free code:

1. Depending on whether the adaptation procedure was previously carried out or not, two cases are considered:

a. If adaptation has not been done before, then a set of reference data is formed, consisting of a sequence of alternating zero and single bits, the bit capacity of which is equal to the number of encoded bits of the BCH code with minimal redundancy;

b. If adaptation was previously performed, then a set of reference data is formed, consisting of a sequence of alternating zero and single bits, the bit capacity of which is equal to the number of encoded bits of the BCH code with the parameters determined at the time of the previous assessment;

2. Data is encoded by the encoder using the selected code and transmitted to the communication channel;

3. The encoded data transmitted through the communication channel is decoded by the decoder;

4. For the decoded data, an encoding efficiency estimate is calculated representing the number of bits of the received data other than the corresponding bits of the reference sequence;

5. If the score is not equal to zero, then in the working table of the BCH codes, the record that stands after the current one is selected, otherwise the record that stands in front of it is selected.

In turn, if a method is used based on a direct assessment of the state of the communication channel:

1. A set of reference data is formed, consisting of a sequence of alternating zero and single bits, the bit capacity of which is equal to the bandwidth of the communication channel, after which the data is transmitted to the communication channel;

2. For the data transmitted via the communication channel, an estimate is generated by comparing them with the reference ones and determining the number of distinct bits;

3. In the working table of BCH codes, the record with the smallest redundancy is selected, the correcting ability of which is greater than or equal to the resulting estimate.

If you use a method based on the calculation of the syndrome of BCH code:

1. Depending on whether the adaptation procedure was previously carried out or not, two cases are considered:

a. If adaptation has not been done before, then a standard data set is used, which is encoded by the BCH encoder with minimal redundancy and transmitted to the communication channel;

b. If adaptation was previously performed, then a standard data set is used, which is encoded by the BCH encoder with the parameters determined at the time of the previous assessment and transmitted to the communication channel;

2. For encoded data transmitted through the communication channel, an estimate is generated by calculating the syndrome;

3. If the score is not equal to zero, then in the working table of the BCH codes, the record that stands after the current one is selected, otherwise the record that stands in front of it is selected.

Choosing between the quality of adaptation and the optimal use of the bandwidth of the communication channel, it is possible to carry out adaptive selection of BCH code parameters.

Thus, this method allows to increase the reliability of data transfer, due to the fact that part of the data bits that cannot be transmitted in the current transmit / receive cycle is placed in the “delayed buffer”, and in case of improvement of the state of the communication channel, a decision is made to transfer data, stored in the buffer, together with the data coming from the data source, and the system itself operates in a continuous mode until all current and placed in the buffer data are transferred.

Claims (1)

A method of transmitting digital information with an adaptive choice of parameters of an anti-interference code, which is based on the principle that if the state of the communication channel does not allow data to be transmitted with the required level of reliability, then in this case a certain number of high-order bits is selected, characterized in that that the remaining low-order bits are placed in a “deferred buffer” organized in the form of a stack with a limited amount, and in case of improvement in the state of the communication channel, a decision is made to transfer the data stored in the buffer together with the data coming from the data source, and the system itself is working in continuous mode, until all relevant and placed in the buffer data is transferred.

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