RU2781567C1 - Method for selecting the transmission rate in radio links - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention relates to the field of radio engineering. The effect is achieved by calculating and obtaining the spectral representation of the test signals, calculating the power value of each of the test signals within the bandwidth of the receiving path, the gradation of which corresponds to the test signal with the corresponding transmission rate, calculating and obtaining the spectral representation of the received information signal within the gradations of the bands transmission of the receiving path, in accordance with the speed of its transmission; in this case, the value of the ratio of the power of the information signal to the spectral density of the noise power is calculated as the ratio of the power value of the test signal corresponding to the bandwidth of the receiving path at which the information signal was received to the power difference between the received information signal and the test signal corresponding to the bandwidth of the receiving path, at which the information signal was received.

EFFECT: providing the possibility of adapting the speed in the radio link depending on the ratio of the signal power to the power of noise and interference, taking into account the possible change in the value of the noise power in the radio link during the transmission of the information message signal.

1 cl, 1 dwg

Description

The invention relates to the field of radio engineering and can be used for adaptive selection of the transmission rate in the radio link based on the results of measuring the current value of the ratio of signal power to noise power and interference in the signal reception band (SNR).

Known system and method for dynamic adaptation of the data rate and transmission power using the beacon transmission protocol (RF patent No. 2381622, H04B 7/005 ).

In a known method for dynamically selecting a data rate and/or transmission power in a communication system including a plurality of devices, including at least one receiver and at least one transmitter, which consists in dividing time per sequence of at least one superframe; embedding in the receiver feedback to the beacon, and the specified feedback on the state or quality of the communication line further comprises at least one of the following: signal-to-noise ratio; received signal level; noise level; burst error rate; bit error rate; path loss and any other characteristic of channel or reception quality.

The disadvantage of the known method lies in the limitations of its application, tk. it only applies to wireless communication systems using the MAC protocol in which devices transmit a beacon.

A known method for selecting the rate of transmission of signal elements in radio modems (RF patent No. 2640431, G01R 23/00 ).

The known method consists in the fact that the signal is received, its spectrum width is measured, the value of which is specified as the signal arrives. The power level of the spectral component of the signal with the maximum amplitude value is measured, and the width of the signal spectrum is measured within the band of its half power, and the decision on the selected transmission rate rating is carried out based on the results of comparing the measured spectrum width values with pre-calculated values corresponding to those rate ratings, for operation with which the radio modems are designed, the desired value is the one with the smallest differences according to the measurement results.

The disadvantage of this method is that it does not provide speed adaptation in the radio link depending on the SNR.

The closest analogue in technical essence to the proposed is a method for selecting the transmission rate in radio links, according to the patent of Russian Federation 2744037, G08C 13/00 taken as a prototype.

The prototype method consists in receiving a signal, measuring the signal power level, measuring the width of the signal spectrum, comparing the measured values with pre-calculated values, making a decision based on the measurement results, and preliminarily, at the receiving end of the radio link, the gradations of the bandwidth of the receiving path are set in accordance with ratings of allowable transmission rates for the radio link, measure the noise level on the receiving side of the radio link and calculate its power spectral density; initially, the transmitted test signal is received at the minimum allowable transmission rate for the radio link, the power level of the test signal is measured and the current value of the ratio of the test signal power to the noise power spectral density is calculated, the calculated current value of the ratio of the test signal power to the noise power spectral density is transmitted to the transmitting side at a minimum acceptable for the radio link speed, set the gradation of the bandwidth of the receiving path in accordance with the allowable transmission rate, determined for the current value of the ratio of the test signal power to the power spectral density of the noise, transmit information messages in the form of packets at a rate determined for the current value of the ratio of the test signal power to noise power spectral density, receive the transmitted signal of the information message for the duration of the packet and measure the corresponding value of the ratio of the power of the information signal the measured value of the ratio of the power of the information signal to the power spectral density of the noise is transmitted to the transmitting side, and if the measured value of the ratio of the power of the information signal to the power spectral density of the noise is less than the calculated value of the ratio of the power of the test signal to the power spectral density of the noise , then on the transmitting side, the transmission rate is reduced by one gradation, and on the receiving side, the bandwidth of the receiving path is reduced by one gradation, and if the measured value of the ratio of the power of the information signal to the spectral power density of the noise is not less than the calculated value of the ratio of the test signal power to the spectral power density noise, then the next packet of information messages is transmitted, these procedures are repeated until all packets of information messages are transmitted.

The disadvantage of the prototype method is that it does not take into account the possibility of changing the value of the noise power in the radio link during the transmission of the information message signal.

The objective of the proposed method is to expand the scope of its application, namely, to provide the possibility of adapting the speed in the radio link depending on the ratio of signal power to the power of noise and interference, taking into account the possible change in the noise power value in the radio link during the transmission of the information message signal.

To solve the problem in the method, which consists in the fact that set the gradation of the bandwidth of the receiving path in accordance with the ratings of the allowable transmission rates for the radio link;

measure the noise level on the receiving side of the radio link and calculate its power spectral density;

receiving the transmitted test signal;

measuring the power level of the test signal and calculating the current value of the ratio of the test signal power to the noise power spectral density;

transmitting the calculated current value of the ratio of the test signal power to the noise power spectral density to the transmitting side at the minimum speed allowed for the radio link;

set the gradation of the bandwidth of the receiving path in accordance with the allowable transmission rate determined for the current value of the ratio of the power of the test signal to the power spectral density of the noise;

transmit information messages in the form of packets at a rate determined for the current value of the ratio of the power of the test signal to the power spectral density of the noise;

receive the transmitted signal of the information message for the duration of the packet and measure the corresponding value of the ratio of the power of the information signal to the power spectral density of the noise;

transmitting the measured value of the ratio of the power of the information signal to the power spectral density of the noise to the transmitting side;

in this case, if the measured value of the ratio of the power of the information signal to the spectral power density of the noise turns out to be less than the calculated value of the ratio of the power of the test signal to the spectral power density of the noise, then on the transmitting side, the transmission rate is reduced by one gradation, and on the receiving side, the bandwidth of the receiving path is reduced by one gradation ;

and if the measured value of the ratio of the power of the information signal to the power spectral density of the noise is not less than the calculated value of the ratio of the power of the test signal to the power spectral density of the noise, then transmit the next packet of information messages;

these procedures are repeated until all packets of information messages are transmitted, according to the invention ,

initially , test signals are transmitted sequentially for each allowable value of the transmission rate,

receive sequentially transmitted test signals within the gradations of the bandwidth of the receiving path in accordance with the ratings of the allowable transmission rates for the radio link;

additionally, when receiving test signals, their spectral representation is calculated and obtained,

and the power value of each of the test signals is calculated within the bandwidth of the receiving path, the gradation of which corresponds to the test signal with the corresponding transmission rate,

and to measure the ratio of the power of the information signal to the power spectral density of the noise, calculate and get the spectral representation of the received information signal within the gradations of the bandwidth of the receiving path, in accordance with its transmission rate;

and directly the value of the ratio of the power of the information signal to the spectral density of the noise power is calculated as the ratio of the power value of the test signal corresponding to the bandwidth of the receiving path at which the information signal was received, to the difference in the powers of the received information signal and the test signal corresponding to the bandwidth of the receiving path, at which the information signal was received.

The operation of radio links, as a rule, is carried out in conditions of noise and interference, the intensity of which can change during a radio session, [Dvornikov S.V. et al. Generalized functional model of a radio link with its frequency resource management. Voprosy radioelectronics. Series: TV Technique. 2016. No. 3. S. 49-56]. As a result of changing the noise level, there is a change in the SNR value in the receive path, [Komarovich V.F., Sosunov V.N. Random radio interference and reliability of KB communication. - M .: "Communication", 1977, 136 s]. Under such conditions, in order to maintain an acceptable value of the error probability in the channel, it is necessary to change the transmission rate adaptively with a change in the current SNR value, [Zaitsev D.V. et al. Method for selecting the transmission rate of signal elements in radio modems. RF patent No. 2640431, G01R 23/00 ].

Ensuring an acceptable value of the error probability in the receive path is possible due to timely adaptation, depending on the SNR value at the receiving end of the radio link, the transmission rate at the transmitting end of the radio link, and changes in the bandwidth of the receiving path.

However, this approach is acceptable only if the SNR value remains unchanged during the transmission of information messages, which is not always ensured in practice, see (Dvornikov S.V. et al. Frequency resource analysis apparatus for the pseudo-random tuning mode of the operating frequency // Information and control Systems, 2019, No. 4 (101), pp. 62-68).

Under such conditions, to ensure stable operation of the radio link, it is necessary to calculate the SNR value taking into account the current value of the noise and interference power level.

Therefore, it is proposed to measure the SNR value in the following way.

At the preliminary stage, the test signal should be presented in the form of several test signals corresponding to the transmission rate values allowed for the given radio link. And then the entire set of test signals is transmitted in such a way that each test signal is received within the gradation of that bandwidth of the receiving path, the gradations of which correspond to its transmission rate.

Then, for each received test signal, it is necessary to form its spectral representation and calculate the power value in accordance with the following expression:

, (1)

, (one)

– модуль спектрального представления обрабатываемого сигнала; m – порядковый номер реализации сигнала;.where

– module of the spectral representation of the processed signal; m is the serial number of the signal realization;

And then, at the stage of receiving the information signal, in accordance with formula (1), calculate its power, and taking into account the power value of the test signal corresponding to the information signal in terms of speed, calculate the SNR value, taking into account the current value of the noise and interference power level (in this In the context, the concept of measuring the SNR value comes from the need to measure the current value of the power of the received information signal and the power of the test signal corresponding to it in terms of transmission rate):

, (2)

, (2)

– текущее значение отношения мощности информационного сигнала к спектральной плотности мощности шумов и помех в радиолинии (данное утверждение справедливо в том случае, когда полезный сигнал, и соответствующий ему по скорости тестовый сигнал имеют одинаковую мощность и одинаковый вид модуляции) в [дБ]; верхний индекс 1 – указывает, что это значение мощности тестового сигнала; верхний индекс 2 – указывает, что это значение мощности полезного сигнала.where

– the current value of the ratio of the power of the information signal to the power spectral density of noise and interference in the radio link (this statement is true in the case when the useful signal and the test signal corresponding to it in speed have the same power and the same type of modulation) in [dB]; superscript 1 - indicates that this is the value of the power of the test signal; superscript 2 - indicates that this is the value of the useful signal strength.

Thus, the calculation by formula (2) ensures that the obtained SNR value takes into account the current values of the noise and interference power in the radio link.

The implementation of these procedures is provided in the claimed technical solution.

The claimed method is illustrated by the drawing, which shows:

и модуль, соответствующего ему по скорости передачи, тестового сигнала

; N2 и N1 – верхняя и нижняя границы полосы частот, в пределах которой рассчитывается мощность сигнала.fig. 1 - information signal spectrum module

and a module corresponding to it in terms of transmission rate, a test signal

; N 2 and N 1 are the upper and lower limits of the frequency band within which the signal power is calculated.

The implementation of the technical solution of the proposed method involves the sequential implementation of the following procedures.

1. The gradations of the bandwidth of the receiving path are set in accordance with the ratings of the allowable transmission rates for the radio link.

The relationship between the width of the signal spectrum and the transmission rate of its elements is known and described, for example, [Zaitsev D.V. et al. Method for selecting the transmission rate of signal elements in radio modems. Patent of the Russian Federation No. 2640431, dated 07/01/2016, G01R 23/00, Published: 01/09/2018 Bull. No. 1].

2. Measure the noise level on the receiving side of the radio link and calculate its power spectral density.

Measurement procedures for received radio emission realizations are known. For example, [Gel V.E. etc. A method for assessing the noise immunity of radio communication lines. Patent of the Russian Federation No. 2613035 C1, dated March 16, 2016, H04L 29/00, Published: 03/14/2017, Bull. No. 8].

3. Initially, test signals are transmitted sequentially for each allowable transmission rate.

To do this, I synthesize my own test signal for each allowable speed value (or use previously accepted ones). Test signals correspond to information signals in terms of transmission rate and modulation type.

Procedures for the emission (transmission) of signals are known. For example, [Gvozdyakov Yu.A. etc. Method of radio suppression of communication channels. RF patent No. 24504584 C1, dated 04/13/2011, H04K 3/00 (2006.01), H04L 27/22 (2006.01), Published: 05/10/2012 Bull. No. 13].

4. Sequentially transmitted test signals are received within the gradations of the bandwidth of the receiving path in accordance with the ratings of the allowable transmission rates for the radio link.

That is, each test signal is received within the gradations of the bandwidth of the receiving path, which corresponds to the bandwidth determined by the transmission rate.

Signal reception procedures are known. For example, [Dvornikov S.V. and other Method of automatic detection of narrow-band signals. Patent RF No. 2382495 C1, dated February 17, 2009, H04B 1/10 (2006.01), Published: February 20, 2010 Bull. No. 5].

5. Additionally, when receiving test signals, their spectral representation is calculated and obtained.

Procedures for calculating and obtaining spectral representations of signals are known. For example, see [Dvornikov S.V. and other Method of automatic detection of narrow-band signals. RF patent No. 2419968 С1, dated 03.08.2009, H04B 1/10 (2006.01), Published: 27.05.2011 Bull. No. 15].

6. And the power value of each of the test signals is measured and calculated within the bandwidth of the receiving path, the gradation of which corresponds to the test signal with the corresponding transmission rate.

Procedures for measuring the power of a test signal are known. For example, [Dvornikov S.V. etc. Method of recognition of radio signals. Patent of the Russian Federation No. 2419147 C1, dated November 23, 2009, G06K 9/00, Published: May 20, 2011, Bull. No. 14].

7. Calculate the current value of the ratio of the power of the test signal to the power spectral density of the noise.

The current SNR value is calculated as the ratio of the measured test signal power to the noise power spectral density calculated during the 2nd stage.

The calculation is made for all gradations of the test signal in terms of speed. As a result of calculations, the number of SNR values is obtained equal to the number of allowable speed gradations for a given radio link.

Formula (1) is used to calculate the power of the test signal in the receive band.

8. The calculated current SNR value is transmitted to the transmitting side at the minimum speed allowed for the radio link.

The current value of the SNR is the value at which the acceptable quality of the useful signal transmission is ensured in terms of the bit error probability for the type of modulation used and the type of error-correcting coding.

Procedures for transmitting information signals are known. For example, [Voznyuk M.A. et al. Operation of radio communication lines with frequency hopping in conditions of intentional interference // Information technologies. 2012. No. 10. S. 64-67].

9. Set the gradation of the bandwidth of the receiving path in accordance with the allowable transmission rate determined for the current SNR value.

The procedures for setting the gradation of the bandwidth of the receiving path in accordance with the allowable transmission rate are known, [Zaitsev D.V. et al. Method for selecting the transmission rate of signal elements in radio modems. Patent of the Russian Federation No. 2640431, dated 07/01/2016, G01R 23/00, Published: 01/09/2018 Bull. No. 1].

10. Information messages are transmitted in the form of packets at a rate determined for the current SNR value.

Packet transmission procedures are known. For example, [Dvornikov S.V. et al. Frequency resource analysis apparatus for pseudo-random tuning of the operating frequency // Information and control systems. 2019. No. 4 (101). S. 62-68].

11. The transmitted information message signal is received for the duration of the packet.

Signal reception procedures are known. For example, [Hot A.V. et al. A method for assessing the noise immunity of radio communication lines of a receiving radio center. Patent of the Russian Federation No. 2633984 C1, dated May 23, 2016, H04L 29/00, Published: October 20, 2017, Bull. No. 29] and [Dvornikov S.V. etc. Method of recognition of radio signals. Patent of the Russian Federation No. 2419147 C1, dated November 23, 2009, G06K 9/00, Published: May 20, 2011, Bull. No. 14].

12. And to measure the ratio of the power of the information signal to the power spectral density of the noise, the spectral representation of the received information signal is calculated and obtained within the gradations of the bandwidths of the receiving path, in accordance with its transmission rate.

The implementation of these procedures is similar to the procedures of step 5.

13. And directly the value of the ratio of the power of the information signal to the spectral power density of the noise is calculated as the ratio of the power value of the test signal corresponding to the bandwidth of the receiving path at which the information signal was received, to the difference in the powers of the received information signal and the test signal corresponding to the bandwidth of the receiving path in which the information signal was received.

This calculation is carried out in accordance with formula (2).

14. The measured SNR value is transmitted to the transmitting side.

The implementation of these procedures is similar to the procedures of step 8.

15. Compare measured value and decide According to the measurement results, if the SNR is less than the pre-calculated SNR value, then on the transmitting side, the transmission rate is reduced by one gradation, and on the receiving side, the bandwidth of the receiving path is reduced by one gradation.

The implementation of the procedures in step 15 is similar to the implementation of the procedures in step 9.

16. If the measured SNR value is not less than the calculated SNR value, then the next packet of information messages is transmitted.

The implementation of the procedures of step 16 is similar to the procedures of step 10.

17. These procedures are repeated until all packets of information messages have been transmitted.

In this case, if during the transmission of packets of information messages, the current SNR value is lower than the value allowed for transmission at the lowest speed for a given radio link, then the transmission of packets of information messages is terminated and a test signal is periodically transmitted until the SNR is established, which allows further transmission of information packets.

The frequency of transmission of the test signal is set on the basis of the empirical experience of previous communication sessions.

и модуль, соответствующего ему по скорости передачи, тестового сигнала

; N2 и N1 – верхняя и нижняя границы полосы частот, в пределах которой рассчитывается мощность сигнала. При этом уровень спектральной плотности мощности шумов и помех на длительности информационного сигнала

выше, чем на длительности тестового сигнала

. Расчеты для представленного на фиг. 1 случая, в соответствии с формулой (2), показали значение ОСШ = 9,2 дБ.As an example, in FIG. 1 shows: information signal spectrum module

and a module corresponding to it in terms of transmission rate, a test signal

; N 2 and N 1 are the upper and lower limits of the frequency band within which the signal power is calculated. At the same time, the level of the spectral power density of noise and interference on the duration of the information signal

higher than the duration of the test signal

. Calculations for shown in Fig. 1 case, in accordance with formula (2), showed the value of SNR = 9.2 dB.

Thus, thanks to the new essential features, a technical result is provided, which consists in adaptively changing the transmission rate on the transmitting side of the radio link and the corresponding choice of the bandwidth of the receiving path on the receiving side of the radio link depending on the SNR, the value of which is calculated as the ratio of the power value of the test signal corresponding to the band the bandwidth of the receiving path at which the information signal was received, to the power difference between the received information signal and the test signal corresponding to the bandwidth of the receiving path, at the value of which the information signal was received.

Claims (19)

A method for selecting a transmission rate in radio links, which consists in setting the gradations of the bandwidth of the receiving path in accordance with the ratings of the allowable transmission rates for the radio link; measure the noise level on the receiving side of the radio link and calculate its power spectral density; receiving the transmitted test signal; measuring the power level of the test signal and calculating the current value of the ratio of the test signal power to the noise power spectral density; transmitting the calculated current value of the ratio of the test signal power to the noise power spectral density to the transmitting side at the minimum speed allowed for the radio link; set the gradation of the bandwidth of the receiving path in accordance with the allowable transmission rate determined for the current value of the ratio of the power of the test signal to the power spectral density of the noise; transmit information messages in the form of packets at a rate determined for the current value of the ratio of the power of the test signal to the power spectral density of the noise; receive the transmitted signal of the information message for the duration of the packet and measure the corresponding value of the ratio of the power of the information signal to the power spectral density of the noise; transmitting the measured value of the ratio of the power of the information signal to the power spectral density of the noise to the transmitting side; in this case, if the measured value of the ratio of the power of the information signal to the spectral power density of the noise is less than the calculated value of the ratio of the power of the test signal to the spectral power density of the noise, then on the transmitting side, the transmission rate is reduced by one gradation, and on the receiving side, the bandwidth of the receiving path is reduced by one gradation ; and if the measured value of the ratio of the power of the information signal to the power spectral density of the noise is not less than the calculated value of the ratio of the power of the test signal to the power spectral density of the noise, then transmit the next packet of information messages; these procedures are repeated until all packets of information messages are transmitted, characterized in that initially sequentially transmit test signals for each valid value of the transmission rate; receive sequentially transmitted test signals within the gradations of the bandwidth of the receiving path in accordance with the ratings of the allowable transmission rates for the radio link; additionally, when receiving test signals, their spectral representation is calculated and obtained; and the power value of each of the test signals is calculated within the bandwidth of the receiving path, the gradation of which corresponds to the test signal with the corresponding transmission rate; and to measure the ratio of the power of the information signal to the power spectral density of the noise, the spectral representation of the received information signal is calculated and obtained within the gradations of the bandwidths of the receiving path, in accordance with its transmission rate; and directly the value of the ratio of the power of the information signal to the spectral density of the noise power is calculated as the ratio of the power value of the test signal corresponding to the bandwidth of the receiving path, at which the information signal was received, to the power difference between the received information signal and the test signal, corresponding to the bandwidth of the receiving path, at which the information signal was received.

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