RU2784378C1 - Method for noise-proof transmission and reception of information based on frequency-shift keyed signals - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to the field of radio engineering and can be used in noise-protected radio-electronic systems (RES), including radio communication systems. To achieve the effect, the formation of frequency-shift keyed signals within the limits allocated for the transmission of frequency intervals is carried out in accordance with the unique available combinations of the selected code, which allows you to correct errors introduced by radio emissions generated by other RES in the frequency band of the generated signal.

EFFECT: increasing the noise immunity of transmission and reception of signals under the influence of radio emissions from third-party RES, localized in the signal reception band.

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Description

The invention relates to the field of radio engineering and is intended for use in noise-protected radio-electronic systems (RES), including radio communication systems.

Known "Method of transmitting information over a short-wave communication channel using frequency-shift keyed signals" (RF Patent No. 2519011, publ. 10.06.2014, Bull. No. 16).

In a known method, signals at subcarrier frequencies are received as independent frequency-spaced amplitude-shift keyed oscillations with an estimate of the signal level and interference, quality is assessed, and a decision is made on the value of the transmitted symbol, which depends on the received estimates of the quality of signals at subcarrier frequencies, and the number of frequency the number of spaced subchannels is equal to the number N, which is more than two, and in each subchannel, to ensure the minimum peak factor of the radio signal, transmission is carried out sequentially in time at one of the M frequencies, emitting radio pulses with a duration N times less than the duration of the transmitted message symbol.

The emission time and frequency of radio pulse emission in each subchannel are selected depending on the value of the transmitted n-element (n=log2(M2V)) symbol, and the decision on the value of the received symbol is made taking into account the quality estimates of the received pulses in each frequency-spaced subchannel according to the ratio criterion the maximum value of the reference obtained from the values of time and frequencies.

However, the known method has a low noise immunity of signal reception in the conditions of radio emissions created by other radio electronic means (RES) in the frequency band of the generated radio emission.

Known "Method of generating a signal with pseudo-random tuning of the operating frequency" (PRFC) (RF Patent No. 2648291. Published 03.23.2018, Bull. No. 9). In the known method, the generation of the primary signal is carried out in the basis of functions of spline characters (BFSH).

Next, it is modulated by a digital sequence. The modulated signal is multiplied with the reference waveform. Moreover, the frequencies of the reference oscillation are determined in accordance with the first given random code digital sequence, and the values of the changing parameters of the FSH are selected in accordance with the second given pseudo-random code digital sequence synchronously with the change in the frequency of the reference oscillation.

However, the known method has a low noise immunity of signal reception in the conditions of radio emissions created by other RES in the frequency band of the generated radio emission.

The closest in technical essence to the claimed invention is the “Method for transmitting information over a short-wave communication channel using frequency-shift keyed signals” (RF Patent No. 2705357, publ. 07.11.2019, Bull. No. 31).

In a method for transmitting information over a short-wave communication channel using frequency-shift keyed signals (FCS), characterized in that the signals at subcarrier frequencies are received as independent frequency-spaced amplitude-shift keyed oscillations, the signal level at subcarrier frequencies is estimated, the radiation at which depends on the value of the transmitted symbol, and make a decision on the value of the received symbol, which depends on the obtained estimates of the quality of the signals on the subcarrier frequencies, characterized in that a code with a constant weight is preselected for coding the subcarriers in such a way that the code bit length corresponds to the number of subcarrier frequencies available for transmission , then the bit stream is divided into information blocks in accordance with the number of available code combinations that determine its alphabet, each information block is assigned its own unique combination of code elements with (UCEC) constant weight, which determines before transmitted symbol, after which signals are generated in the form of amplitude-shift keyed oscillations (AMEC) for the duration of each transmitted symbol only at those subcarrier frequencies that correspond to information units determined by a combination of code elements with a constant weight, and the resulting frequency-shift keyed signal is formed by additive addition fluctuations of all subcarrier frequencies and receive the resulting frequency-shift keyed signal at subcarrier frequencies as independent frequency-spaced amplitude-shift keyed oscillations, while estimating the signal quality at subcarrier frequencies by comparing the calculated average value of the power of its spectral components within each of the subcarrier frequencies with the calculated value the average value of the signal power for the duration of the received symbol at all subcarrier frequencies, and the decision to transmit an information unit within each of the subcarrier frequencies is made if the calculated average e value of the power of the spectral components within the subcarrier frequency exceeds the calculated value of the average power value for the duration of the received symbol at all subcarrier frequencies, otherwise a decision is made to transmit an information zero.

The disadvantage of the known prototype method is the relatively low noise immunity of the reception, due to the inability to correct errors introduced by radio emissions generated by other RES in the frequency band of the generated signal.

The objective of the invention is to create a method that allows you to generate frequency-shift keyed signals within the frequency intervals allocated for transmission in accordance with the unique available combinations of the selected code, which allows you to correct errors introduced by radio emissions generated by other RES in the frequency band of the generated signal.

The technical result is to increase the noise immunity of transmission and reception of signals under the influence of radio emissions from third-party RES, localized in the signal reception band.

The technical result is achieved by the fact that in the method of transmitting and receiving information based on frequency-shift keyed signals, which consists in the fact that when generating a frequency modulated signal to be transmitted, a code is selected for subcarrier frequencies for encoding them in such a way that the code bit length corresponds to the number of available to transmit subcarriers, then split

the bit stream to be transmitted to information blocks, assign to each information block its own unique combination of code elements, which determines the transmitted symbol, after which signals are generated in the form of amplitude-shift keyed oscillations for the duration of each transmitted symbol only at those subcarrier frequencies that correspond to information units , determined by a unique combination of code elements, and the resulting FSK signal is formed by additive addition of oscillations of all subcarrier frequencies and transmitted, the resulting FSK signal is received at subcarrier frequencies as independent frequency-spaced amplitude-shift keyed oscillations, while the signal quality is estimated at subcarrier frequencies by comparing the calculated average value of the power of its spectral components within each of the subcarrier frequencies with the calculated average value of the signal power for a duration of the received symbol at all subcarrier frequencies, and the decision to transmit an information unit within each of the subcarrier frequencies is made if the calculated average value of the power of the spectral components within the subcarrier frequency exceeds the calculated average power value for the duration of the received symbol at all subcarrier frequencies, otherwise, a decision is made to transmit an information zero, a generating polynomial is additionally formed for the selected code of information blocks, and a unique combination of code elements is formed by multiplying the information block by the generating polynomial, and at the receiving end of the communication channel, test data is preliminarily formed, for which each unique combination of code elements is sequentially introduced by one erroneous value, starting from the least significant digit, and the resulting residuals are calculated by dividing each unique combination of code elements with an inserted erroneous value by the waiting polynomial, match the bit number containing the erroneous value and the value of the calculated resulting remainder, form the accepted unique combination of code elements based on the results of deciding on the transmitted zero or one on subcarriers within the symbol, check the received unique combination of code elements for the presence there are errors in it, for which it is divided by a generating polynomial and the resulting remainder is calculated, if the resulting remainder is zero, then it is considered that there are no errors in the generated received unique combination of code elements, and it is passed to the consumer if the value of the resulting remainder is different from zero, then it is matched with the number of the bit containing the erroneous value, in accordance with the pre-calculated test data, the error is corrected in the generated received unique combination of code elements, and transmitted to the consumer.

The introduction of new essential features makes it possible, by selecting unique code combinations used to modulate signal symbols, to detect an error caused by interference from third-party radio electronic equipment at the reception.

The claimed method is illustrated by drawings, which show:

fig. 1 - spectrum formed on the transmitting side of the resulting FMS, which corresponds to UKEC 1001110, within the frequency range from F2 to F 1;

fig. 2 - the spectrum of the received FMS, which corresponds to UKEC 1001110, within the frequency range from F2 to F1, in noise conditions, with the calculated value of the threshold G;

fig. 3 - the spectrum of the received FMS, which corresponds to the UKEC 1001111, within the frequency range from F2 to F1, in terms of noise and interference, with the calculated value of the threshold G. The spectrum of the interference signal, which led to an error in the last bit of the UKEC, is designated as FX.

In FIG. 1-3, the numbering of the UKEC bits is from right to left, starting from the upper frequency F2 to the lower F1.

The implementation of the proposed method in accordance with Fig. 1 - fig. 3 is carried out as follows.

1. Select a code for coding subcarriers in such a way that the code bit length corresponds to the number of subcarriers available for transmission. The procedures of paragraph 1 are similar to the procedures described in the prototype method.

2. A generating polynomial is preliminarily formed for the selected code, and a unique combination of code elements is formed by multiplying the information block by the generating polynomial. The procedures for generating a generating polynomial for the selected code are known, for example, see (Zolotarev VV Codes and coding. - M.: Knowledge, 1990. 64 p.).

So, for example, for the Hamming code (7.4), the generating polynomial will look like 1011, and for the information block 1010 of the UKEC it will look like 1001110. Hereinafter, all examples are given for the Hamming code (7.4).

3. Each information block is assigned its own unique combination of code elements with a constant weight, which determines the transmitted character.

The bit stream is divided into information blocks in accordance with the capabilities of the code. For example, for a Hamming code (7,4), an information block of 4 bits will correspond to a UKEC consisting of 7 bits.

Accordingly, in this case, the number of subcarriers available for transmission should be equal to 7.

These procedures are known, for example, see (Dvornikov S.V., Popov E.A., Balykov A.A., Dvornikov S.S. Noise immunity of signals with permutable frequency modulation in channels with constant parameters with incoherent reception // Radio engineering. 2019. V. 83. No. 12 (20), pp. 24-31.).

4. After that, signals are formed in the form of AMK for the duration of each transmitted symbol only at those subcarrier frequencies that correspond to information units determined by a unique combination of code elements.

These procedures are known, for example, see (Dvornikov S.V., Balykov A.A. Proposals for controlling the transmission rate and noise immunity of signals with permutable frequency modulation // T-Comm: Telecommunications and transport. 2020. V. 14. No. 6 pp. 20-26.).

As an example, in FIG. 1 shows the spectrum of the resulting FMS formed on the transmitting side, which corresponds to UKEC 1001110, within the frequency range from F2 to F1. Hereinafter, the boundaries of the subranges, within the range from F2 to F1, in which AMECs are formed, are shown by a dotted line. The presence of spectral

component within the frequency subband corresponds to information bit 1.

5. Moreover, the resulting FMS is formed by additive addition of oscillations of all subcarrier frequencies and transmitted. The procedures for additive addition of oscillations on subcarriers are known, for example, see (Dvornikov S.V., Ovchinnikov G.R., Balykov A.A. Software simulator of the decameter ionospheric radio channel // Information and space. 2019. No. 3. P. 6 -12.).

The procedures for transmitting the generated signal are known, for example, see (RF Patent No. 2450458 dated May 10, 2012. Method of radio jamming of communication channels).

6. And at the receiving end of the communication channel, verification data is preliminarily generated, for which one erroneous value is sequentially introduced into each UCER, starting from the least significant digit, and the resulting residuals are calculated by dividing each UCEC with an inserted erroneous value by a generating polynomial. The procedures for calculating the remainder for the selected code are known, for example, see (Zolotarev VV Codes and coding. - M.: Knowledge, 1990. 64 p.). For example, for UKEC 1001110, in which the error is entered in the first digit from the right (the least significant bit), in which the UKEC takes the form 1001111, the resulting remainder is 001. In this case, if there are no errors in the UKEC, the resulting remainder is 000.

7. Match the number of the digit, which contains the erroneous value, and the value of the calculated resulting balance. For the example discussed in paragraph 6, the least significant digit corresponds to the resulting remainder 001.

8. Receive the resulting FMR at subcarrier frequencies as independent frequency-spaced AMKs. Signal reception procedures are known, for example, see (Patent for

invention RU 2382495 C1, dated February 20, 2010. Method for automatic detection of narrowband signals).

9. At the same time, the quality of the signal at subcarrier frequencies is estimated by comparing the calculated average value of the power of its spectral components within each of the subcarrier frequencies with the calculated value of the average signal power for the duration of the received symbol at all subcarrier frequencies, and the decision to transmit an information unit within each of the subcarrier frequencies, they are accepted if the calculated average value of the power of the spectral components within the subcarrier frequency exceeds the calculated value of the average power value for the duration of the received symbol at all subcarrier frequencies, otherwise a decision is made to transmit an information zero. The procedures of paragraph 9 are similar to the procedures described in the prototype method.

As an example, in FIG. 2 shows the spectrum of the received FMS within the frequency range from F2 to F1, under noisy conditions, with the calculated value of the threshold G.

10. Form the adopted UKER based on the results of the decision on the transmitted zero or one on the subcarriers within the symbol. The adopted UKER is formed by setting one in the event that within the subrange the power of the spectral components exceeded the calculated threshold value. As an example, in FIG. 2 shows the spectrum of the received HMS, which is compliant with UKEC 1001110, within the frequency range from F2 to F 1.

11. Check the received UKER for the presence of errors in it, for which it is divided by the generating polynomial and the resulting remainder is calculated, if the resulting remainder is zero, then it is considered that there are no errors in the generated received UKER, and it is transmitted to the consumer.

The procedures of clause 11 are similar to those of clause 6. For the example in question in FIG. 2, the formed accepted UKEC is equal to 1001110. And the calculated resulting balance will look like LLC, which indicates its equality to zero.

12. If the value of the resulting remainder is different from zero, then it is assigned the number of the digit that contains the erroneous value, in accordance with the previously calculated verification data.

As an example, in FIG. 3 shows the spectrum of the received FMS, which corresponds to UKEC 1001111, within the frequency range from F2 to F1, under noise and interference conditions, with the calculated value of the threshold G. This UKEC 1001111 contains an error in the least significant bit caused by the spectrum of the interference signal FX contained in within

subrange corresponding to the least significant digit. For this UKEK 1001111, the value of the resulting remainder is non-zero and equal to 001, which allows it to correspond to the least significant digit. That is, this type of resulting remainder indicates the presence of an error in the least significant digit of the UKEC. These procedures are discussed in clause 7.

13. An error is corrected in the generated received PCEC and transmitted to the consumer (i.e., the generated received PCEC with the corrected error is transmitted to the consumer).

Error correction is carried out by replacing the value of a bit in the corresponding bit.

For example, in UKEC 1001111 the corrected version will look like 1001110.

Based on the foregoing, the technical result of the invention is achieved.

In the prototype, the transmission of signals in the presence of interference (outside radiation) located within the frequency band of the receive channel leads to errors. The technical solution used in the prototype method can only detect the very fact of an error in the duration of the received signal symbol.

The proposed method allows, by selecting unique code combinations, to identify a subcarrier whose frequency band contains interfering radiation from third-party electronic equipment and correct the error that occurs.

Claims (1)

A method for transmitting and receiving information based on frequency-shift keyed signals, which consists in the fact that when generating a frequency-modulated signal to be transmitted, a code is selected for subcarrier frequencies for encoding them in such a way that the code bit length corresponds to the number of subcarrier frequencies available for transmission, then the bit stream to be transmitted is divided into information blocks, each information block is assigned its own unique combination of code elements that determines the transmitted symbol, after which signals are generated in the form of amplitude-shift keyed oscillations for the duration of each transmitted symbol only at those subcarrier frequencies that correspond to the information units determined by a unique combination of code elements, and form the resulting frequency-shift keyed signal by additive addition of oscillations of all subcarrier frequencies and transmit it, receive the resulting frequency-shift keyed signal on subcarrier frequencies as independent frequency-spaced amplitude-shift keyed oscillations, while assessing the quality of the signal at subcarrier frequencies by comparing the calculated average power value of its spectral components within each of the subcarrier frequencies with the calculated average signal power value for the duration of the received symbol at all subcarrier frequencies , and the decision to transmit an information unit within each of the subcarrier frequencies is made if the calculated average value of the power of the spectral components within the subcarrier frequency exceeds the calculated value of the average power value for the duration of the received symbol at all subcarrier frequencies, and otherwise a decision is made about transmission of an information zero, characterized in that a generating polynomial is preliminarily formed for the selected code of information blocks, and a unique combination of code elements is formed by multiplying the information block by n generating a polynomial, and at the receiving end of the communication channel, check data is preliminarily generated, for which one erroneous value is sequentially introduced into each unique combination of code elements, starting from the least significant digit, and the resulting residuals are calculated by dividing each unique combination of code elements with the introduced erroneous value by the generating polynomial, match the number of the bit containing the erroneous value and the value of the calculated resulting remainder, form the accepted unique combination of code elements based on the results of deciding on the transmitted zero or one on subcarriers within the symbol, check the received unique combination of code elements for the presence of errors, for which it is divided by a generating polynomial and the resulting remainder is calculated; Since its remainder is different from zero, then the number of the digit containing the erroneous value is assigned to it, in accordance with the pre-calculated verification data, the error is corrected in the generated received unique combination of code elements and transferred to the consumer.

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