RU2806795C1 - Structural-frequency method of increasing noise immunity of radio data transmission channel - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: intended for use in radio communication systems (RCS) using a structural-frequency method for increasing the noise immunity of a Manchester code digital frequency-modulated radio signal. The structure-frequency method of increasing the noise immunity of a radio data transmission channel additionally consists in the fact that before starting work, synchronization of the transmitting and receiving party is ensured by pre-programming the mode of synchronous tuning of the operating frequency according to a pseudo-randomly. On the transmitting party, the digital information bit sequences of the Manchester code, depending on the signal-interference situation, are expanded with a given Barker code with the possibility of n-fold multiplexing of each bit with the selected Barker code, forming a frequency-modulated broadband noise-like radio signal of the Manchester code with low power spectral density below the density level power of natural radio interference and transmit it to the receiving side, synchronized with the transmitting party. In this case, each information bit sequence of the Manchester code is transmitted on a different frequency channel in accordance with a given pseudo-random frequency mode. At the receiving side, the Barker code is demodulated into a digital information bit sequence of the Manchester code.

EFFECT: increasing the structural, energy and frequency security of the radio signal and, as a consequence, to increase the noise immunity of the radio channel.

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Description

The invention relates to the field of radio engineering and is intended for use in radio communication systems (RCS) using a structural-frequency method of increasing the noise immunity of a Manchester code digital frequency-modulated radio signal.

A known method for generating noise-like radio pulses for transmitting binary symbols of information using complex signals (Patent No. 2231924 Russian Federation, MGZH N04V 1/69 (2006.01). Method for generating noise-like radio pulses for transmitting binary symbols of information using complex signals: No. 2003100971: application 13.01.2003: publ. 06.27.2004 / Zasenko V.E., Prosviryakova L.V. - 7 p.: ill. Text: direct).

In the known method, minimal code-frequency modulation of the carrier frequency is carried out by summing the oscillations of quadrature channels modulated in amplitude and phase, the modulating code sequences of which are obtained by recoding the code sequence of a noise-like radio pulse, gating the resulting sum with a video pulse equal to the duration of the code sequence, the formation of the opposite signal is carried out by inverting the code of the modulating code sequences of one of the quadrature channels.

The disadvantage of this known method is the relatively low structural and frequency secrecy of the generated signal due to the small value of its base and the lack of technical operations to use the mode of pseudo-random tuning of operating frequencies and, as a consequence, low noise immunity of the radio channel.

A known method for transmitting binary information by complex signals with intrapulse minimum frequency shift keying (Patent No. 2358404 Russian Federation, IPC H01L 27/10. Method of transmitting binary information by complex signals with intrapulse minimum frequency shift keying: published 06/10/2009, Bulletin No. 16).

In the known method, minimal code-frequency modulation of the carrier frequency is carried out by summing amplitude- and phase-modulated oscillations of quadrature channels. Why are modulation codes generated for the quadrature and in-phase components of a complex signal with the bit frequency of the information sequence? Determine even and odd clock intervals, even and odd unit bits of the information sequence. Modulation code sequences of the sine and cosine channels are generated and quadrature modulation codes located at even intervals of the sine channel are replaced with in-phase modulation codes of even intervals of the cosine channel and vice versa. Then the resulting sequences are converted into a bipolar code and phase-modulated sine and cosine harmonic oscillations of the subcarrier frequency, the period of which is equal to four times the duration of the elementary burst of the code used, after which the phase-modulated oscillations are fed to a quadrature carrier frequency modulator.

The disadvantage of this known method is the relatively low structural and frequency secrecy of the generated signal due to the small value of its base and the lack of technical operations to use the mode of pseudo-random tuning of operating frequencies and, as a consequence, low noise immunity of the radio channel.

The closest in technical essence to the claimed invention and taken as a prototype is the Method for generating structurally covert, noise-proof single-sideband modulation radio signals using Barker codes (Patent No. 2749877 Russian Federation, IPC H04L 5/00 (2021.02). Method for generating structurally covert, noise-proof single-sideband modulation radio signals using Barker codes: No. 2022118853: application 06/01/2020: published 06/18/2021 / Kryachko A.F., Dvornikov S.V., Pshenichnikov A.V., Manaenko S.S., Glukhikh I. N., Dvornikov S.S. - 11 p.: ill. Text: direct).

In the prototype method, technology is used to increase the structural secrecy of the signal with control of the suitability of operating frequencies. On the transmitting side, information and test bit sequences are formed, each bit of the information and test sequences is expanded with a Barker code, a radio signal is generated and transmitted, on the receiving side the received radio signal is demodulated and calculated mutual correlations of demodulated signal sequences in the Barker code interval, which are compared with a threshold value, evaluate the state of the radio channel, based on the evaluation results, make a decision on the further operation of the radio link, while combining the test and information sequences into a common sequence so that the number of bits of the information sequence is not less than than 10 times the number of bits of the test sequence; radio pulses are formed by modulating the bits of the general sequence, respectively, with direct and inverse wavelet functions of arbitrary order; based on the generated radio pulses, a single-sideband modulation radio signal is formed, which is emitted in the direction of the receiving side; on the receiving side, demodulation of the single-sideband signal is carried out; calculating the cross-correlation of the general sequence of demodulated radio pulses with sequences of radio pulses corresponding to Barker codes modulated by direct and inverse wavelet functions of arbitrary order, similar on the transmitting side; after comparing the correlation results with the threshold values, an information sequence of bits is selected and transmitted to the recipient; the test bit sequence is compared with the original test sequence and the state of the radio channel is assessed; if the received test bit sequence coincides with the original test sequence, then a decision is made about the suitability of the radio channel, and if it does not match, then the radio channel is considered unsuitable, the receiving path is tuned to a new frequency, known in advance on the transmitting side; from the received test sequence of bits, response radio pulses are similarly formed, modulated and transmitted over a radio channel at the frequency at which the reception was carried out; at the transmitting frequency, a response radio signal is received, it is processed in a similar way and the resulting response test bit sequence is compared with the original test sequence; if the received response test bit sequence coincides with the original test sequence, then single-sideband modulation radio signals are similarly formed from subsequent information bit sequences and transmitted in the radio channel at the same frequency; if the response and initial test sequences do not match, then the radio channel is considered unsuitable and the transmitting path is tuned to a new frequency to which the receiving path on the receiving side has already been adjusted and initially repeat the transmission of the information sequence that was previously transmitted over the unusable radio channel; These actions are performed until all information sequences have been transmitted.

The disadvantage of the prototype method is the relatively low structural and energy secrecy of the generated signal, due to the limited possibilities for expanding the base of a broadband signal, which has a low power spectral density in a given signal-interference environment and is proportional to the Barker code used (3, 4, 5, 7, 11, 13 bits), as well as insufficient frequency secrecy, due to the lack of technical operations to use the mode of pseudo-random tuning of operating frequencies, which results in low noise immunity of the radio channel.

A new technical solution is aimed at eliminating these shortcomings, namely the Structure-frequency method of increasing the noise immunity of a radio data transmission channel.

The objective of the present invention is to create a method that makes it possible to generate, based on a digital frequency-modulated signal of the Manchester code, energetically secretive broadband noise-like radio signals using Barker codes, and also provides frequency concealment by changing the operating frequency of the transmitted radio signal in the mode of pseudo-random tuning of operating frequencies.

The technical result of the proposed method is to increase the structural, energy and frequency secrecy of the radio signal and, as a consequence, to increase the noise immunity of the radio channel.

A structural-frequency method of increasing the noise immunity of a radio data transmission channel, which consists in forming an information bit sequence on the transmitting side, each bit of which is expanded with a Barker code. Based on the generated radio pulses, a radio signal is generated, which is emitted in the direction of the receiving side. At the receiving side, the signal is demodulated, the information sequence of bits is isolated and transmitted to the recipient.

The fundamental difference from the prototype is that before starting work, synchronization of the transmitting and receiving sides is ensured through preliminary programming of the mode of synchronous adjustment of the operating frequency according to a pseudo-random law. On the transmitting side, the digital information bit sequences of the Manchester code, depending on the signal-interference situation, are expanded with a given Barker code with the possibility of n-fold multiplexing of each bit with the selected Barker code, forming a frequency-modulated broadband noise-like radio signal of the Manchester code with low power spectral density below the density level power of natural radio interference and transmit it to the receiving side, synchronized with the transmitting side. In this case, each information bit sequence of the Manchester code is transmitted on a different frequency channel in accordance with a given pseudo-random frequency mode. At the receiving side, the Barker code is demodulated into a digital information bit sequence of the Manchester code.

The technical result is achieved due to a set of new essential features, consisting in the synchronization of the transmitting and receiving sides to simultaneously ensure the mode of changing the operating frequency of the transmitted signal according to a pseudo-random law to ensure frequency secrecy and the formation of broadband noise-like radio signals of low spectral power density of a given base, depending on the given signal- interference environment, ensuring their energy secrecy below the level of natural interference based on encoding the original frequency-modulated signals with various Barker sequences with the possibility of n-fold bit compression, which results in increased structural and energy secrecy, and, as a consequence, noise immunity of the radio channel.

The claimed method is illustrated by drawings, which show:

fig. 1, a - formation of a digital information bit sequence;

fig. 1, b - principle of encoding a digital information bit sequence with Manchester code;

fig. 1, c - the principle of expanding the digital information bit sequence of the Manchester code with a three-element Barker code, with the possibility of n-fold compaction;

fig. 1, d - the principle of modulation of Manchester code radio pulses, extended by a three-element Barker code, by frequency modulation of bits;

In fig. 1, and the principle of formation of a digital information bit sequence is presented.

In fig. 1, b, shows a fragment of the digital information bit sequence of the Manchester code.

In fig. 1, c, shows the principle of expanding the digital information bit sequence of the Manchester code with a three-element Barker code.

In fig. 1, d, shows the principle of modulation of a generated sequence of radio pulses, which corresponds to four pulses extended by a three-element Barker code.

Implementation of the method

The structural-frequency method of increasing the noise immunity of a radio data transmission channel is as follows: before starting operation of the radio channel, it is necessary to ensure synchronization of the transmitting and receiving sides through preliminary programming of the mode of synchronous tuning of the operating frequency according to a pseudo-random law, and also to determine the sequence of the Barker code that ensures structural and energy secrecy in a given (supposed) signal-interference environment. On the transmitting side, a digital information bit sequence of the Manchester code is formed. As a result, sequences of pulses corresponding to logical “0” and “1” are obtained. This information bit sequence of the Manchester code is expanded with a given Barker code, with the possibility of n-fold compaction. To expand the pulses corresponding to logical “1” and “0”, direct and inverse forms of the Barker code are used, which provide proportional expansion of the base and the formation of a noise-like signal of low power spectral density below the level of natural radio interference.

Next, radio pulses are formed by frequency modulation of the bits of the digital information sequence of the Manchester code. Each encoded sequence is emitted on a different frequency radio channel, in accordance with the specified tuning mode to a pseudo-random operating frequency, provided that the tuning time to the next frequency channel will not exceed the guaranteed search time, determined by the parameters of the transmitted command and the possible number of frequency radio channels.

On the receiving side, the received signal is tuned from a pseudo-random frequency to an operating frequency, the frequency is transferred to intermediate frequencies and the Barker code is demodulated into a digital information bit sequence of the Manchester code. The result of demodulation is a digital information bit sequence of Manchester code radio pulses.

The next information bit sequence of the Manchester code is transmitted on another frequency channel in accordance with the program of pseudo-random adjustment of the operating frequency. The frequency also changes at certain programmed intervals.

Thus, in the claimed invention, its implementation ensures an increase in structural, energy and frequency secrecy and, as a consequence, an increase in the noise immunity of the radio channel.

The claimed method is industrially applicable, since its implementation uses widely used components and products of the radio engineering industry and computer technology.

Claims (1)

A structural-frequency method of increasing the noise immunity of a radio data transmission channel, which consists in forming an information bit sequence on the transmitting side, each bit of which is expanded with a Barker code; based on the generated radio pulses, a radio signal is formed, which is emitted in the direction of the receiving side; on the receiving side, the signal is demodulated, the information sequence of bits is isolated and transmitted to the recipient, characterized in that before starting work, the transmitting and receiving sides are synchronized by pre-programming the mode of synchronous tuning of the operating frequency according to a pseudo-random law; on the transmitting side, the digital information bit sequences of the Manchester code, depending on the signal-interference situation, are expanded with a given Barker code with the possibility of n-fold multiplexing of each bit with the selected Barker code, forming a frequency-modulated broadband noise-like radio signal of the Manchester code with low power spectral density below the density level power of natural radio interference and transmit it to the receiving side, synchronized with the transmitting side; in this case, each information bit sequence of the Manchester code is transmitted on a different frequency channel in accordance with a given pseudo-random frequency mode; On the receiving side, the Barker code is demodulated into a digital information bit sequence of the Manchester code.

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