RU2799491C1 - Operating frequency control method - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention is intended for use in frequency-adaptive radio communication systems. The message transmission cycle is divided into three subcycles with constant and equal durations, the interference level is measured for the duration of the first subcycle, and radio signals are formed at the upper and lower operating frequencies for the duration of the second and third subcycles. Each possible combination formed from three information bits, according to the rule agreed with the receiving side, is assigned a unique type of radio signal, which is formed in the form of a harmonic oscillation on the upper subcarrier or on the lower subcarrier of the operating frequency for the duration of both the second and third subcycles, or for the duration of only the second, or only the third subcycle, or in the form of a signal structure, in which for the duration of the second subcycle form a harmonic oscillation on the upper subcarrier, and for the duration of the third subcycle form a harmonic oscillation on the lower subcarrier, or vice versa; combinations.

EFFECT: increased efficiency of changing unsuitable operating frequencies in the process of transmitting blocks of information data.

1 cl, 9 dwg, 1 tbl

Description

The invention relates to the field of radio engineering and is intended for use in frequency-adaptive radio communication systems.

Known "Transmission method with active control of operating frequencies" (RF Patent No. 2778551, IPC H04B 1/713, publ. 22.08.2022. Bull. No. 24).

In the known method of transmission with active control of operating frequencies, the data transmission systems on the receiving and transmitting sides are rebuilt from one frequency to another frequency absolutely synchronously. The transmitting side is informed about the quality of the communication channel at the frequency at which the reception was carried out, at the same time at the moment when the reception is performed at the current frequency. At the same time, the transmitting party is informed about the quality of the communication channel at the previous frequency and a decision is made on the choice of the operating frequency. A set of operating frequencies is preliminarily set at which information messages will be transmitted and received. The algorithm for tuning operating frequencies and the procedure for selecting operating frequencies for transmitting information messages are known both on the transmitting side and on the receiving side. Information messages are divided into blocks of information data, which are transmitted by means of packets additionally containing a service part, while each packet is assigned an individual number contained in the service part. The duration of the packet is chosen so that it coincides with the transmission time interval on one frequency. Packets are transmitted in accordance with the operating frequency tuning algorithm, if the channel quality at one of the operating frequencies does not meet the requirements, then a decision is made to exclude it from the operating frequency set, and the packet that was transmitted at the operating frequency excluded from the operating frequency set , retransmit on any other frequency, in accordance with the frequency hopping algorithm. If, during the further transmission of information data, an inappropriate channel quality is again detected at one of the operating frequencies, then this frequency is also excluded from the set of operating frequencies. Similarly, they act until all blocks of information data are transmitted, and on the receiving side, the received information data is formed in accordance with the individual packet numbers contained in their service part.

The disadvantage of the known method is the low efficiency of changing unsuitable operating frequencies during the transmission of information, which occurs only after the transmitting party is informed about the channel quality.

There is a known method for active control of operating frequencies with identification of the type of destructive effects, see (RF Patent No. 2734754, IPC H04B 1/713 (2020.05); H04B 3/46 (2020.05), publ. 23.10.2020 Bull. No. 30).

In the well-known method of active control of operating frequencies with identification of the type of destructive effects, the information source sequentially sends a pre-prepared test data block, known on the receiving side, at each of the possible operating frequencies. In this case, the data transmission systems on the receiving and transmitting sides are tuned from frequency to frequency absolutely synchronously, the information receiver evaluates the parameters of the communication channel at the corresponding operating frequency and informs the transmitting side about the quality of the communication channel. After obtaining the necessary statistics for the entire allocated frequency resource, a decision is made on the choice of the operating frequency for data transmission. The transmitting side is informed about the channel quality at the frequency at which the prepared test block was received. At the same time, at the moment when the prepared test block is received at the current operating frequency, the transmitting side is simultaneously informed about the channel quality at the previous operating frequency. Based on the analysis performed, the allowable number of usable operating frequencies is calculated, at which the application of the test procedures still provides the required data transfer rate. If the total number of unusable frequencies exceeds the calculated allowable number, then a test signal is additionally transmitted at each identified unusable operating frequency, and a structural analysis of the features of its distortion is performed on the receiving side at each operating frequency at which it was transmitted. The results of the structural analysis are compared with previously prepared reference values, based on the results of comparison with which a decision is made on the type of destructive impact and, if necessary, the parameters and modes of operation of the data transmission system are changed.

The disadvantage of the known method is the low efficiency of changing unsuitable operating frequencies during the transmission of information, which occurs only after the transmitting party is informed about the channel quality.

The closest in technical essence (prototype) to the claimed one is the “Method of active control of operating frequencies” (RF Patent No. 2710027, IPC H04B 1/713, publ. 24.12.2019. Bull. No. 36).

In the prototype method, on the transmitting side, the information source sequentially sends, on each frequency allocated for operation, a pre-prepared test data block known on the receiving side. In this case, the data transmission systems on the receiving and transmitting sides are tuned from one frequency to another frequency absolutely synchronously. The information receiver sequentially evaluates the parameters of the communication channel at each frequency allocated for operation, the quality of the communication channel is reported to the transmitting side. After obtaining the necessary statistics for the entire allocated frequency resource, a decision is made on the choice of the operating frequency for data transmission. At the same time, the transmitting side is informed about the channel quality at the frequency at which the prepared test block was received. At the same time, at the moment when the prepared test block is received at the current frequency, the transmitting side is simultaneously informed about the quality of the communication channel at the previous frequency.

The disadvantage of the known method is the low efficiency of changing unsuitable operating frequencies during the transmission of information, which occurs only after the transmitting party is informed about the channel quality.

The objective of the invention is to implement procedures for monitoring the current state of operating frequencies immediately before the transmission of information data blocks over them.

The technical result of the proposed method is to increase the efficiency of changing unsuitable operating frequencies in the process of transmitting blocks of information data.

The claimed technical result is achieved by the fact that in the method of controlling operating frequencies, which consists in the fact that the information source sends a pre-prepared test data block known on the receiving side at each of the possible operating frequencies, while the data transmission systems on the receiving and transmitting sides are rebuilt with frequency to frequency absolutely synchronously, the information receiver evaluates the parameters of the communication channel at the corresponding operating frequency and, after obtaining the necessary statistics for the entire allocated frequency resource, decides on the choice of operating frequencies for data transmission, according to the invention, operating frequencies are selected with a separation of at least two kilohertz, then they are ranked according to the results of estimating the parameters of communication channels, after which a list of operating frequencies is formed, which is transmitted to the receiving side at a pre-prepared frequency, then the first operating frequency is selected for transmission from the list of operating frequencies, and the message transmission time cycle is divided into three subcycles with constant and equal durations, for the duration of the first subcycle, the level of interference is measured at the first operating frequency from the list of operating frequencies, if the measured level of interference exceeds the permissible value, then the operating frequency selected for transmission is changed to the next one from the list of operating frequencies, and radiation is not carried out for the duration of the second and third subcycles , which for the receiving side is a command to switch to the next operating frequency from the list of operating frequencies, if the measured interference level is less than the permissible level, then information data is transmitted in the form of bits, for which information bits are divided into blocks consisting of three bits, while for transmission of information data bits use radio signals that form on the upper and lower subcarriers of the operating frequencies, while the frequencies of the upper and lower subcarriers of the operating frequency are selected by five hundred hertz, respectively, more and less than the value of the operating frequency, and each possible combination formed from three information bits, according to a rule agreed upon with the receiving side, a unique type of radio signal is assigned, which is formed in the form of a harmonic oscillation on the upper subcarrier or on the lower subcarrier of the operating frequency for the duration of both the second and third subcycles, or for the duration of only the second, or only the third subcycle, or in the form of a signal structure, in which a harmonic oscillation is formed on the upper subcarrier for the duration of the second subcycle, and a harmonic oscillation is formed on the lower subcarrier for the duration of the third subcycle, or vice versa; if the last operating frequency from the list of operating frequencies turns out to be unsuitable, then the transmission of information bits is stopped, and on the second and third subcycles, a harmonic oscillation is formed and emitted at a pre-prepared frequency, which is a command to the receiving side to stop receiving information bits, after which the operating frequencies are replaced , followed by repeated execution of these procedures.

Thanks to a new set of essential features in the proposed method, the implementation of procedures for monitoring the current state of operating frequencies is carried out immediately before the transmission of information data blocks over them, which makes it possible to increase the efficiency of changing unsuitable operating frequencies.

Let us explain the possibility of achieving the specified technical result.

In the prototype method, the decision on the suitability or unsuitability of the operating frequencies is carried out based on the results of the reverse control, i.e. after receiving a message from the transmitting party about the quality of the channel.

In the claimed method, the operating frequency control procedure is carried out before the transmission of blocks of information data, which provides an increase in efficiency compared to the prototype method.

In addition, in the proposed method, the formation of radio signals at the duration of the second and third transmission subcycles is carried out using the upper and lower subcarriers at each operating frequency. This makes it possible to expand the alphabet of codewords used to encode blocks of information data, which consist of three bits.

As a result of the application of such a technical solution, it becomes possible to evaluate the channel parameters for the duration of the first subcycle, the results of which make a decision on the suitability of the channel immediately before the transmission of blocks of information data.

The claimed method is illustrated in Fig. 1 - fig. 9 showing:

Fig. 1. Harmonic oscillation U _pc ( t ), formed within the 2nd and 3rd subcycles at the carrier frequency of the operating frequency channel;

Fig. 2. The generated radio signal U _pc ( t ) on the lower subcarrier within the 2nd subframe, corresponding to a code combination of three bits equal to 000;

Fig. 3. The generated radio signal U _pc ( t ) on the upper subcarrier within the 2nd subframe, corresponding to a code combination of three bits equal to 001;

Fig. 4. The generated radio signal U _pc ( t ) on the upper subcarrier within the 3rd subcycle, corresponding to a code combination of three bits equal to 010;

Fig. 5. The generated radio signal U _pc ( t ) on the lower subcarrier within the 3rd subcycle, corresponding to a code combination of three bits equal to 011;

Fig. 6. The generated radio signal U _pc ( t ) on the lower subcarrier within the 2nd subcycle and on the upper subcarrier within the 3rd subcycle, corresponding to a codeword of three bits equal to 100;

Fig. 7. The generated radio signal U _pc ( t ) on the upper subcarrier within the 2nd subcycle and on the lower subcarrier within the 3rd subcycle, corresponding to a three-bit codeword equal to 101;

Fig. 8. The generated radio signal U _pc ( t ) on the lower subcarrier within the 2nd subcycle and on the upper subcarrier within the 3rd subcycle, corresponding to a three-bit codeword equal to 110;

Fig. 9. The generated radio signal U _pc ( t ) on the upper subcarrier within the 2nd subframe and on the upper subcarrier within the 3rd subframe, corresponding to a codeword of three bits equal to 111.

The inventive method is carried out as follows:

1. Operating frequencies are selected with a spacing of at least two kilohertz. Therefore, the difference between the first and second operating frequencies must be at least f ₂ = f ₁ + 2 kHz.

2. The information source sends a pre-prepared test data block known on the receiving side at each of the possible operating frequencies. In this case, the data transmission systems on the receiving and transmitting sides are tuned from frequency to frequency absolutely synchronously.

3. The information receiver evaluates the parameters of the communication channel at the corresponding operating frequency and, after receiving the necessary statistics for the entire allocated frequency resource, decides on the choice of operating frequencies for data transmission.

4. Operating frequencies are ranked according to the results of estimating the parameters of communication channels.

The communication channel parameter can be, for example, the error probability, which is described in (RF Patent No. 2707572, IPC H04B 1/713 "Method for adaptive data transmission in a radio link with pseudo-random tuning of the operating frequency", publ. 28.11.2019 Bull. No. 34 ).

5. After that, a list of operating frequencies is formed, which is transmitted to the receiving side at a pre-prepared frequency. The use of feedback channels is known from (Komarovich V.F., Sosunov V.N. Random radio interference and reliability of KB communications. - M .: "Communication", 1977, 136 p. See pages 92-98).

The first number in the specified list is the operating frequency with the best estimate of the channel parameters. Next, the frequencies are placed as their estimates deteriorate.

It is advisable to implement this operation on the basis of microprocessor technology. The procedure for selecting the parameters of the microprocessor, its interface with external elements is described in (Patent of the Russian Federation No. 2273099, IPC N 04V 15/00, "Radio link with software tuning of the operating frequency", publ. 03.27.2006, bull. No. 9).

A pre-prepared frequency is chosen before a communication session, its value is known both on the receiving and transmitting sides.

As a pre-prepared frequency, the frequency at which information transmission is provided with the required quality is selected. The very operation of transmitting a list of operating frequencies is similar to transmitting a test block at one frequency.

6. For transmission, the first operating frequency is selected from the list of operating frequencies, and the message transmission time cycle is divided into three subcycles
with constant and equal durations.

The duration of the subcycles is selected based on the required transmission rate, as well as the parameters of the radio channel, see, for example, (Komarovich V.F., Sosunov V.N. Random radio interference and reliability of HF communications. - M .: "Communication", 1977) .

7. For the duration of the first subcycle measure the level of interference at the first operating frequency from the list of operating frequencies.

Interference level measurement is a well-known operation and is implemented, for example, in the R-170P series radio receiver, R-016V frequency adaptation equipment and is based on the use of amplitude detectors, the implementation of which is given, for example, in (RF Patent No. 2093951, IPC H 03D 1/ 18, "Amplitude detector" publ. 10/20/1997), or interference power meters, see, for example, (RF Patent No. real time" publ. 28.06.2017. Bull. No. 19) or (Patent of the Russian Federation No. 2640431, IPC G01R 23/00 (2006.01), "Method for selecting the rate of transmission of signal elements in radio modems" pub. 09.01.2018 Bull. No. 1 ).

8. If the measured noise level exceeds the allowable value, then the operating frequency selected for transmission is changed to the next one from the list of operating frequencies, and radiation is not carried out for the duration of the second and third subcycles, which is a command for the receiving side to switch to the next operating frequency from the list of operating frequencies. frequencies.

This procedure is based on a comparison of the measured noise level with a threshold, is known and can be implemented on the basis of microprocessor technology. Technically, the comparison of the level of interference with the threshold is implemented, for example, in the AT-3104D radio modem, R-016V frequency adaptation equipment, or, for example, in (RF Patent No. 2005, Bull. No. 1).

This procedure implements the transmission of a command to the receiving side to change the operating frequency, i.e. to select the next frequency from the list of operating frequencies. The change of operating frequencies on the receiving and transmitting sides occurs absolutely synchronously, similar to the specified procedure in the prototype method.

9. If the measured noise level is less than the permissible level, then information data is transmitted, for which information bits are divided into blocks consisting of three bits. At the same time, radio signals are used to transmit bits of information data, which are formed on the upper and lower subcarriers of operating frequencies. In this case, the frequency values of the upper and lower subcarriers of the operating frequency are chosen to be five hundred hertz, respectively, more and less than the value of the operating frequency. Moreover, each possible combination formed from three information bits, according to the rule agreed with the receiving side, is assigned a unique type of radio signal, which is formed in the form of a harmonic oscillation on the upper subcarrier or on the lower subcarrier of the operating frequency for the duration of both the second and third subcycles, or for the duration of only the second, or only the third subcycle, or in the form of a signal structure, in which a harmonic oscillation is formed on the upper subcarrier for the duration of the second subcycle, and a harmonic oscillation is formed on the lower subcarrier for the duration of the third subcycle, or vice versa.

These technical operations are based on signal coding for the duration of the second and third time subcycles by a block of three information bits.

In this case, the choice of matching a combination of three information bits to a unique type of radio signal can be arbitrary, but known both on the receiving side and on the transmitting side.

An example of such a correspondence is presented in Table 1.

Table 1

2 subcycle 3 subcycle information bit encoding 000 lower subcarrier 001 upper subcarrier 010 upper subcarrier 011 lower subcarrier 100 lower subcarrier upper subcarrier 101 upper subcarrier lower subcarrier 110 lower subcarrier lower subcarrier 111 upper subcarrier upper subcarrier service command coding shift team
operating frequency stop command
transmission of information Harmonic oscillation at a preset frequency Harmonic oscillation at a preset frequency

In FIG. 2 - fig. 9 shows examples of unique types of radio signals generated in accordance with the bit encoding presented in table. 1.

The procedure for generating a harmonic wave at subcarrier frequencies or at a pre-prepared frequency is known, and can be implemented based on the use of radio transmitter exciters, for example, the R-170V or V series (RF Patent No. 2625527, IPC H 04V 1/02, "Exciter for radio transmitters" , publ. 07/14/2017. Bull. No. 20), (RF Patent No. 2261476, IPC G 06 K 9/00, "Method for recognizing radio signals", publ. 09.27.2005. Bull. No. 27).

In this case, the algorithm for generating radio signals in accordance with Table. 1 on the durations of the second and third subcycles at operating frequencies can be implemented on the basis of microprocessor technology that controls the frequency synthesizer in the transmitter, see, for example, (RF Patent No. 2223597, IPC H 03L 7/18, "Digital Frequency Synthesizer" publ. February 10, 2004. Bulletin No. 4).

10. If the last operating frequency from the list of operating frequencies turns out to be unsuitable, then the transmission of information bits is stopped, and on the second and third subcycles, a harmonic oscillation is formed and emitted at a pre-prepared frequency, which is a command to the receiving side to stop receiving information bits, after which the replacement is carried out operating frequencies, followed by the specified procedures.

This operation is implemented by sequentially re-implementing the procedures in accordance with paragraphs 1-10 for other operating frequencies.

As an example, figure 1 shows the harmonic oscillation U _PC ( t ), formed within the 2nd and 3rd subcycles on the carrier frequency of the operating frequency channel.

Simulation of the procedures of the proposed method for controlling operating frequencies in the MathLAB environment confirmed the increase in the efficiency of changing unsuitable operating frequencies during the transmission of blocks of information data. Depending on the number of unusable frequencies, the increase in efficiency reached 70% compared with the prototype method, which indicates the achievement of the task and the technical result of the invention.

Claims (1)

A method for controlling operating frequencies, which consists in the fact that the information source sends a pre-prepared test data block, known on the receiving side, at each of the possible operating frequencies, while the data transmission systems on the receiving and transmitting sides are tuned from frequency to frequency absolutely synchronously, the information receiver evaluates the parameters of the communication channel at the corresponding operating frequency, and after obtaining the necessary statistics for the entire allocated frequency resource, they make a decision on the choice of operating frequencies for data transmission, characterized in that the operating frequencies are selected with a spacing of at least two kilohertz, then they are ranked according to the results of parameter estimation communication channels, after which a list of operating frequencies is formed, which is transmitted to the receiving side at a previously prepared frequency, then the first operating frequency is selected for transmission from the list of operating frequencies, and the message transmission time cycle is divided into three subcycles with constant and equal durations, by the duration of the first subcycle the level of interference is measured at the first operating frequency from the list of operating frequencies, if the measured level of interference exceeds the permissible value, then the operating frequency selected for transmission is changed to the next one from the list of operating frequencies, and radiation is not performed for the duration of the second and third subcycles, which for the receiving side is a command to move to the next operating frequency from the list of operating frequencies, if the measured interference level is less than the permissible level, then information data is transmitted in the form of bits, for which information bits are divided into blocks consisting of three bits, while radio signals are used to transmit information data bits , which are formed at the upper and lower subcarriers of the operating frequencies, while the frequencies of the upper and lower subcarriers of the operating frequencies are chosen by five hundred hertz, respectively, more and less than the value of the operating frequency, and each possible combination formed from three information bits, according to the rule agreed with the receiving side , assign a unique type of radio signal, which is formed in the form of a harmonic oscillation on the upper subcarrier or on the lower subcarrier of the operating frequency for the duration of both the second and third subcycles, or for the duration of only the second or only the third subcycle, or in the form of a signal structure, y which for the duration of the second subcycle form a harmonic oscillation on the upper subcarrier, and for the duration of the third subcycle form a harmonic oscillation on the lower subcarrier, or vice versa; if the last operating frequency from the list of operating frequencies turns out to be unsuitable, then the transmission of information bits is stopped, and on the second and third subcycles, a harmonic oscillation is formed and emitted at a pre-prepared frequency, which is a command to the receiving side to stop receiving information bits, after which the operating frequencies are replaced , followed by repeated execution of these procedures.

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