Method for controlling operating frequencies
By synchronously evaluating channel parameters at the receiving end and using a four-subcycle transmission method, the method addresses the issue of interference environment unawareness at the receiving end, improving frequency selection reliability and transmission efficiency in radio communication systems.
Patent Information
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- FEDERALNOE GOSUDARSTVENNOE AVTONOMNOE OBRAZOVATELNOE UCHREZHDENIE VYSSHEGO OBRAZOVANIYA SANKT PETERBURGSKIJ GOSUDARSTVENNYJ UNIV AEROKOSMICHESKOGO PRIBOROSTROENIYA
- Filing Date
- 2026-02-24
- Publication Date
- 2026-07-06
AI Technical Summary
Existing frequency selection methods in radio communication systems fail to account for interference environments at the receiving end of the radio link, leading to potential mismatches in suitable operating frequencies.
Implement a method where the information source sends a pre-prepared test data block on each possible operating frequency, with data transmission systems synchronously switching between frequencies, allowing the receiving side to evaluate channel parameters and make decisions on frequency suitability, using a four-subcycle transmission time structure to ensure accurate selection and confirmation of suitable frequencies.
This approach enhances the reliability and efficiency of selecting suitable operating frequencies by considering interference at the receiving end, ensuring accurate channel suitability assessment and reducing transmission errors.
Smart Images
Figure 00000001_ABST
Abstract
Description
[0001] The invention relates to the field of radio engineering and is intended for use in frequency-adaptive radio communication systems.
[0002] A transmission method with active frequency control is known (RU Patent No. 2778551, H04B 1 / 713, published August 22, 2022). This method involves synchronously configuring data transmission systems on the transmitting and receiving sides from one frequency to another. The transmitting side is informed of the communication channel quality on the frequency on which reception was made, while reception is taking place on the current frequency. Simultaneously, the transmitting side is informed of the communication channel quality on the previous frequency, and a decision is made on the operating frequency selection. A set of operating frequencies on which information messages will be transmitted and received is predetermined. The frequency configuring algorithm and the procedure for selecting operating frequencies for transmitting information messages are known to both the transmitting and receiving sides.Information messages are divided into data blocks, which are transmitted via packets that also contain a service section. Each packet is assigned a unique number contained in the service section. The packet duration is selected so that it coincides with the transmission time interval on a single frequency. Packets are transmitted in accordance with a frequency hopping algorithm. If the channel quality on one of the operating frequencies does not meet requirements, a decision is made to exclude it from the set of operating frequencies, and the packet transmitted on the excluded frequency is retransmitted on any other frequency, in accordance with the frequency hopping algorithm. If, during subsequent data transmission, inadequate channel quality is again detected on one of the operating frequencies, that frequency is also excluded from the set of operating frequencies.The same procedure is followed until all blocks of information data have been transmitted, and on the receiving side the received information data is formed in accordance with the individual packet numbers contained in their service part.
[0003] The disadvantage of the known method is that the decision on the suitability of the operating frequency is made at the transmitting end of the radio line, without taking into account the interference environment at the receiving end of the radio line.
[0004] A known method for actively monitoring operating frequencies with identification of the type of destructive impacts (RU Patent 2734754, H04B 1 / 713, H04B 3 / 46, published 23.10.2020). In this known method for actively monitoring operating frequencies with identification of the type of destructive impacts, the information source sequentially transmits a pre-prepared test data block, known to the receiving side, at each of the possible operating frequencies. In this case, the data transmission systems on the receiving and transmitting sides toggle from frequency to frequency absolutely synchronously, the information receiver evaluates the communication channel parameters at the corresponding operating frequency and informs the transmitting side about the communication channel quality. After obtaining the necessary statistics for the entire allocated frequency resource, a decision is made on the selection of an 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, when a prepared test block is received on the current operating frequency, the transmitting side is simultaneously informed of the channel quality on the previous operating frequency. Based on this analysis, the permissible number of suitable operating frequencies is calculated, at which the testing procedures still ensure the required data transfer rate. If the total number of unsuitable frequencies exceeds the calculated permissible number, then an additional test signal is transmitted on each identified unsuitable operating frequency, and the receiving side performs a structural analysis of its distortion characteristics at each operating frequency on which it was transmitted. The results of the structural analysis are compared with pre-prepared reference values, based on which a decision is made on the type of destructive impact and, if necessary, modifications to the parameters and operating modes of the data transmission system.
[0005] The disadvantage of the known method is that the decision on the suitability of the operating frequency is made at the transmitting end of the radio line, without taking into account the interference environment at the receiving end of the radio line.
[0006] A method for actively monitoring operating frequencies is known (Russian Federation Patent No. 2710027, H04B 1 / 713, published December 24, 2019). In this method, the transmitting source sequentially transmits a pre-prepared test data block, known to the receiving side, on each frequency allocated for operation. In this case, the data transmission systems on the receiving and transmitting sides toggle from one frequency to another in complete synchronism. The information receiver sequentially evaluates the communication channel parameters on each frequency allocated for operation, and the transmitting side is informed of the communication channel quality. After obtaining the necessary statistics for the entire allocated frequency resource, a decision is made on the operating frequency for data transmission. At the same time, the transmitting side is informed of the channel quality on the frequency on which the prepared test block was received.At the same time, at the moment when the prepared test block is received on the current frequency, the transmitting side is simultaneously informed about the quality of the communication channel on the previous frequency.
[0007] The disadvantage of the known method is that the decision on the suitability of the operating frequency is made at the transmitting end of the radio line, without taking into account the interference environment at the receiving end of the radio line.
[0008] The closest in technical essence (prototype) to the claimed invention is a method for monitoring operating frequencies
[0009] (Patent of the Russian Federation No. 2799491, H04B 3 / 46, published 07 / 05 / 2023). In the prototype method, the information source on the transmitting side sends a pre-prepared test data block, known at the receiving side, on 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 receiving the necessary statistics for the entire allocated frequency resource, makes a decision on the selection of operating frequencies for data transmission. In this case, the operating frequencies are selected with a spacing of at least two kilohertz, then they are ranked based on the results of the evaluation of the communication channel parameters, after which a list of operating frequencies is formed, which is transmitted to the receiving side on a pre-prepared frequency, then the first operating frequency from the list of operating frequencies is selected for transmission,and the time cycle of message transmission is divided into three sub-cycles with constant and equal durations, during the duration of the first sub-cycle the interference level is measured at the first operating frequency from the list of operating frequencies, if the measured interference level exceeds the permissible value, then the operating frequency selected for transmission is changed to the next one from the list of operating frequencies, and during the duration of the second and third sub-cycles no emission is performed, 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 value, then the transmission of information data in the form of bits is carried out, for which the information bits are divided into blocks consisting of three bits, while for the transmission of bits of information data radio signals are used that are formed on the upper and lower subcarriers of the operating frequencies,wherein the frequency values of the upper and lower subcarriers of the operating frequencies are selected to be five hundred hertz higher and lower, respectively, 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 party, 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; if the last operating frequency from the list of operating frequencies proves to be unsuitable, then the transmission of information bits is terminated,and in 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 a repeat execution of the specified procedures.
[0010] A drawback of the prototype method is that the decision on the suitability or unsuitability of operating frequencies is based on interference level measurements at the transmitting end of the radio link, without taking into account the interference environment at the receiving end. As a result, it is possible that a channel at the operating frequency at one end of the radio link will be suitable but unsuitable at the other. For example, due to the presence of a powerful source of either unintentional or intentional interference nearby.
[0011] The objective of the invention is to take into account the interference environment at the receiving end of a radio link when implementing procedures for monitoring the current state of operating frequencies immediately before transmitting information data blocks over them.
[0012] The technical result of the claimed method is to increase the reliability of the correct selection of suitable operating frequencies in the process of transmitting blocks of information data.
[0013] The claimed technical result is achieved by the fact that in the method of monitoring operating frequencies, which consists in the fact that the information source sends a pre-prepared test data block on each of the possible operating frequencies, known on the receiving side, wherein 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 on the corresponding operating frequency and after receiving the necessary statistics for the entire allocated frequency resource, a decision is made on the selection of operating frequencies for data transmission, wherein the operating frequencies are selected with a spacing of at least two kilohertz, then they are ranked based on the results of the evaluation of the parameters of the communication channels, after which a list of operating frequencies is formed, which is transmitted to the receiving side on a pre-prepared frequency, then the first operating frequency from the list of operating frequencies is selected for transmission,and the time cycle of message transmission is divided into three sub-cycles with constant and equal durations, if the operating frequency selected for transmission does not meet the requirements, then it is changed to the next one from the list of operating frequencies, and if it does meet the requirements, then the information data is transmitted in the form of bits, for which the information bits are divided into blocks, if the last operating frequency from the list of operating frequencies turns out to be unsuitable, then the transmission of information bits is stopped, after which the operating frequencies are replaced from among the reserve ones, with subsequent repeated execution of the specified procedures, given that the time cycle of message transmission is divided into four sub-cycles with constant and equal durations, during the duration of the first sub-cycle the code combination is transmitted on the first operating frequency from the list of operating frequencies to the receiving side, during the duration of the second sub-cycle from the receiving side the received code combination is transmitted to the transmitting side,during the duration of the third subcycle, the transmitting side performs a check of the correspondence of the transmitted and received code combinations at the first operating frequency from the list of operating frequencies; if the transmitted and received code combinations do not correspond to each other, then the operating frequency selected for transmission is changed to the next one from the list of operating frequencies, and during the duration of the fourth subcycle, no emission is performed, which for the receiving side is a command to switch to the next operating frequency from the list of operating frequencies; if the transmitted and received code combinations correspond to each other, then during the duration of the fourth subcycle, a repeated transmission of the code combination is performed from the transmitting to the receiving side; if the last operating frequency from the list of operating frequencies turns out to be unsuitable, then during the fourth subcycle, an amplitude modulation signal modulated by a meander is formed and emitted at the last operating frequency,which is a command to the receiving side to stop receiving information bits.
[0014] Thanks to a new set of essential features in the claimed 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, taking into account the interference environment at the receiving end of the radio link, which ensures an increase in the reliability of the correct selection of suitable operating frequencies in the process of transmitting information data blocks.
[0015] The possibility of achieving the specified technical result comes from the fact that in the claimed method, the procedure for monitoring the suitability of the channel at operating frequencies is carried out after repeated reception of the transmitted signal, but already from the receiving side, which ensures an increase in the reliability of the correct selection of suitable operating frequencies in the process of transmitting blocks of information data.
[0016] Furthermore, the claimed method uses four subcycles, which increases the receiver's confidence in the channel's availability. Thus, the absence of transmissions (signal emission) during the fourth subcycle indicates the need to change the operating frequency. And repeated transmission of the original code combination during the fourth subcycle indicates the channel's availability at the operating frequency.
[0017] As a result of the application of such a technical solution, it becomes possible not only to increase the reliability of the correct selection of suitable operating frequencies during the transmission of information data blocks, but also the efficiency of the transmission of information data, due to an accurate understanding of the situation with the suitability of the channel.
[0018] The claimed method is illustrated by Figs. 1-3, which show:
[0019] Fig. 1 - a transmission time cycle with a duration of four subcycles with constant and equal intervals, provided that the current channel is unsuitable and a change of the operating frequency is necessary.
[0020] Fig. 2 - a transmission time cycle with a duration of four sub-cycles with constant and equal intervals, provided that the current channel is suitable and there is no need to change the operating frequency.
[0021] Fig. 3 - a transmission time cycle with a duration of four sub-cycles with constant and equal intervals, provided that the current channel is unsuitable, the selected working frequencies are finished and it is necessary to stop receiving information bits at the receiving end.
[0022] The claimed method is carried out as follows.
[0023] 1. Operating frequencies are selected with a separation of at least two kilohertz. Therefore, the difference between the first and second operating frequencies should be no less than f2 = f1 + 2 kHz.
[0024] 2. The information source sends a pre-prepared test data block known to the receiving end on each of the possible operating frequencies. The data transmission systems on both the receiving and transmitting ends switch from frequency to frequency in complete synchrony.
[0025] 3. The information receiver evaluates the communication channel parameters at the corresponding operating frequency and, after receiving the necessary statistics for the entire allocated frequency resource, makes a decision on the selection of operating frequencies for data transmission.
[0026] 4. Operating frequencies are ranked based on the results of evaluating the communication channel parameters.
[0027] The communication channel parameter can be, for example, the error probability.
[0028] 5. After which a list of operating frequencies is formed, which is transmitted to the receiving side on a pre-prepared frequency. The use of feedback channels is known from (Komarovich V.F., Sosunov V.N. Random radio interference and the reliability of HF communications. - Moscow: "Svyaz", 1977, 136 p. See pp. 92-98).
[0029] The operating frequency with the best channel parameter estimate is placed first in the specified list. The frequencies are then ranked in descending order of their estimates.
[0030] It is advisable to implement this operation on the basis of microprocessor technology.
[0031] A pre-prepared frequency is selected before the communication session, its value is known on both the receiving and transmitting sides.
[0032] The pre-prepared frequency is selected as the frequency that ensures data transmission with the required quality. The operation of transmitting the list of operating frequencies is similar to transmitting a test block on a single frequency.
[0033] 6. For transmission, the first operating frequency from the list of operating frequencies is selected, and the message transmission time cycle is divided into four sub-cycles with constant and equal durations.
[0034] The duration of the subcycles is selected based on the required transmission speed, as well as the parameters of the radio channel, see, for example, (Komarovich V.F., Sosunov V.N. Random radio interference and the reliability of HF communications. - M.: "Svyaz", 1977).
[0035] 7. During the duration of the first subcycle, the code combination is transmitted on the first operating frequency from the list of operating frequencies to the receiving side.
[0036] An example of transmitting a code combination during the duration of the first subcycle is shown in Fig. 1 (the cycle is designated as T1).
[0037] 8. During the second sub-cycle, the received code combination is transmitted from the receiving side to the transmitting side.
[0038] An example of transmitting a code combination during the second subcycle is shown in Fig. 1 (the cycle is designated as T2).
[0039] 9. During the third sub-cycle, the transmitting side performs a check to ensure that the transmitted and received code combinations match at the first operating frequency from the list of operating frequencies.
[0040] An example of checking the correspondence of the transmitted and received code combinations for the duration of the third subcycle is shown in Fig. 1 (the cycle is designated as T3).
[0041] The test can be performed either by matching the transmitted and received bits, or by measuring the interference level at the first operating frequency from the list of operating frequencies.
[0042] Measuring the interference level is a well-known operation and is implemented, for example, in the R-170P series radio receiver, the R-016V frequency adaptation equipment and is based on the use of amplitude detectors or interference power meters.
[0043] 10. If the transmitted and received code combinations do not match, the operating frequency selected for transmission is changed to the next one from the list of operating frequencies, and no transmission occurs during the duration of the fourth subcycle, which is a command for the receiving side to switch to the next operating frequency from the list of operating frequencies.
[0044] An example of the absence of radiation for the duration of the fourth sub-cycle, which corresponds to the unsuitability of the channel, is shown in Fig. 1 (the cycle is designated as T4).
[0045] 11. If the transmitted and received code combinations correspond to each other, then during the fourth sub-cycle, the code combinations are retransmitted from the transmitting to the receiving side, after which the information data is transmitted in the form of bits, for which the information bits are divided into blocks.
[0046] An example of retransmission of a code combination during the duration of the fourth sub-cycle, which corresponds to the suitability of the channel, is shown in Fig. 2 (the cycle is designated as T4).
[0047] 12. If the last operating frequency from the list of operating frequencies is unsuitable, then the transmission of information bits is stopped, and in the fourth subcycle, an amplitude modulation signal modulated by a square wave is generated and emitted at the last operating frequency, which is a command to the receiving side to stop receiving information bits.
[0048] An example of transmitting an amplitude modulation signal modulated by a square wave for the duration of the fourth subcycle, which is a command to the receiving side to stop receiving information bits, is shown in Fig. 3 (the cycle is designated as T4).
[0049] This operation is implemented by sequentially repeating the procedures for other operating frequencies.
[0050] The simulation of the procedures of the claimed method for monitoring operating frequencies in the MathLAB environment confirmed an increase in the reliability of the correct selection of suitable operating frequencies in the process of transmitting blocks of information data and the efficiency in the course of transmitting information data due to an accurate understanding of the situation with the suitability of the channel, which indicates the achievement of the objective and technical result of the invention.
Claims
A method of monitoring operating frequencies, which consists in the fact that the information source sends a pre-prepared test data block, known at the receiving end, on each of the possible operating frequencies, wherein 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 on the corresponding operating frequency and, after receiving the necessary statistics for the entire allocated frequency resource, makes a decision on the selection of operating frequencies for data transmission, wherein the operating frequencies are selected with a spacing of at least two kilohertz, then they are ranked according to the results of the evaluation of the parameters of the communication channels, after which a list of operating frequencies is formed, which is transmitted to the receiving side on a pre-prepared frequency, then the first operating frequency from the list of operating frequencies is selected for transmission, and the time cycle of message transmission is divided into three sub-cycles with constant and equal durations,if the operating frequency selected for transmission does not meet the requirements, then it is changed to the next one from the list of operating frequencies, and if it does meet the requirements, then the information data is transmitted in the form of bits, for which the information bits are divided into blocks, if the last operating frequency from the list of operating frequencies turns out to be unsuitable, then the transmission of information bits is stopped, after which the operating frequencies are replaced from among the reserve ones, with subsequent repeated execution of the specified procedures, characterized in that the time cycle of message transmission is divided into four sub-cycles with constant and equal durations, during the duration of the first sub-cycle the code combination is transmitted on the first operating frequency from the list of operating frequencies to the receiving side, during the duration of the second sub-cycle from the receiving side the received code combination is transmitted to the transmitting side,during the duration of the third subcycle, the transmitting side performs a check of the correspondence of the transmitted and received code combinations at the first operating frequency from the list of operating frequencies; if the transmitted and received code combinations do not correspond to each other, then the operating frequency selected for transmission is changed to the next one from the list of operating frequencies, and during the duration of the fourth subcycle, no emission is performed, which for the receiving side is a command to switch to the next operating frequency from the list of operating frequencies; if the transmitted and received code combinations correspond to each other, then during the duration of the fourth subcycle, a repeated transmission of the code combination is performed from the transmitting to the receiving side; if the last operating frequency from the list of operating frequencies turns out to be unsuitable, then during the fourth subcycle, an amplitude modulation signal modulated by a meander is formed and emitted at the last operating frequency,which is a command to the receiving side to stop receiving information bits.