Interactive channel scanning frequency selection method for short-wave radio station

Abstract

The invention belongs to the field of short-wave communication, and particularly relates to an interactive channel scanning frequency selection method for a short-wave radio station, which comprises the following steps that: before formal communication, a sender sequentially sends detection signals with different frequencies to a receiver, and the receiver carries out signal-to-noise ratio estimation on the received detection signals so as to obtain a passable frequency; then, the receiver feeds back the passable frequency to the sender, the sender obtains the first passable frequency through analysis, then selects all frequencies before the first passable frequency and sequentially sends corresponding detection signals to the receiver, the receiver estimates the signal-to-noise ratio after receiving the detection signals, all channels are screened according to all the signal-to-noise ratios, and therefore the optimal frequency is obtained; and then the receiver feeds back the optimal frequency to the sender. According to the method provided by the invention, the passability and the communication efficiency can be greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of shortwave communication, and specifically relates to a method for interactive channel scanning frequency selection for shortwave radios. Background Technology

[0002] The increasing information technology of modern society and the growing emphasis on shortwave communication worldwide have made the shortwave communication environment increasingly complex. Shortwave communication relies primarily on the reflection of radio waves by the ionosphere and is affected by sunlight. For example, the communication performance of the same frequency varies significantly at dawn, noon, dusk, and night; it's possible for communication to be available at midday but not at night. Therefore, the frequency used for shortwave communication must be determined before it can be used to transmit information.

[0003] Chinese utility model patent CN202713279U, entitled "A Shortwave Frequency Selection Terminal," designs a frequency selection terminal including a shortwave long-term prediction unit to monitor and analyze shortwave frequencies and select superior frequencies. Chinese invention patent CN10247718A, entitled "Frequency Selection Method, Device, Computer Equipment, and Storage Medium Based on Shortwave Communication," proposes a method: determining the corresponding communication frequency band based on communication parameters, thereby determining the initial call frequency; the master station sends empty data packets to the slave station according to the initial call frequency; and the communication frequency between the master and slave stations is determined based on the response message sent by the slave station. Chinese invention patent CN108924909A, entitled "A Fast Shortwave Frequency Selection Link Establishment Method," discloses a fast frequency selection method where the master station continuously sends one or more PDU protocols on the same frequency, and the slave station switches between different frequencies in the communication frequency set to achieve PDU reception and parsing. If a single link establishment attempt fails, automatic detection is automatically triggered until the link establishment is completed, and the successful frequency is recorded for priority use in the next communication. The aforementioned existing technical solutions all rely on historical experience to generate a set of communication frequencies or on continuous testing and switching at a single frequency point to select the final communication frequency. These methods depend on historical values ​​to predict the current communication frequency, thus the predictions are prone to error. Furthermore, some shortwave radios require operators to select frequencies from historical communication frequency sets based on their experience and manually search for frequency bands using the radio's built-in receiver module, subjectively judging channel availability and failing to obtain the true signal-to-noise ratio of the channel.

[0004] Whether relying on empirical values ​​to predict the current communication frequency or on the operator's experience to select the frequency, it is difficult to guarantee the quality of frequency selection, and the success rate of shortwave communication is reduced.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and propose a method for interactive channel scanning frequency selection for shortwave radio. This method is performed before formal communication between the two parties and aims to determine the frequency used during formal communication, thus solving the problem of how to quickly and accurately determine the frequency used during shortwave communication.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for interactive channel scanning frequency selection for shortwave radio. Before formal communication, the transmitter sequentially sends probe signals of different frequencies to the receiver. The receiver estimates the signal-to-noise ratio (SNR) of the received probe signals to obtain the passable frequencies. The receiver then feeds back the passable frequencies to the transmitter. The transmitter analyzes the signals to obtain the first passable frequency, then selects all frequencies before the first passable frequency and sequentially sends the corresponding probe signals to the receiver. After receiving the signals, the receiver estimates the SNR and filters each channel based on all SNRs to obtain the optimal frequency. The receiver then feeds back the optimal frequency to the transmitter.

[0008] Furthermore, the transmitter is shortwave radio A, and the receiver is shortwave radio B. Both shortwave radio A and shortwave radio B are capable of receiving signals of any frequency, and receive signals of one frequency at a time.

[0009] Furthermore, the process of obtaining the available frequency includes a dwell phase, a synchronization phase, and an available frequency feedback phase; The dwell phase specifically refers to: shortwave radio station A transmitting frequencies sequentially before formal communication. f 1~ f N The detection signal was detected by shortwave radio station B at frequency [frequency not specified]. f 1~ f N The station stays for a set duration. Once shortwave radio B receives the first detection signal, it changes its receiving frequency to enter the synchronization phase. The synchronization phase specifically involves the following steps: After entering the synchronization phase, shortwave radio station B continues to receive detection signals until all frequencies of detection signals have been received. Shortwave radio station B then performs a signal-to-noise ratio (SNR) estimation on the received detection signals. If the SNR is -∞ dB, the corresponding frequency is not passable; otherwise, it is a passable frequency.

[0010] Furthermore, the available frequency feedback stage specifically involves the shortwave radio station B transmitting the frequency... f 1~ f N Feedback signals containing PDUs are sent sequentially to shortwave radio station A according to the set time slots. Each PDU carries a passable frequency.

[0011] Furthermore, the process of obtaining the optimal frequency includes a detection phase and an optimal frequency feedback phase; The detection phase specifically involves: after parsing the PDU, shortwave radio A determines the frequency corresponding to when shortwave radio B enters the synchronization phase. Shortwave radio A then sequentially sends corresponding detection signals to frequencies transmitted before that frequency. Shortwave radio B estimates the signal-to-noise ratio of the received detection signals and, in conjunction with the signal-to-noise ratio obtained during the synchronization phase, selects the optimal frequency after comparison.

[0012] Furthermore, the optimal frequency feedback stage specifically involves the shortwave radio station B transmitting the frequency... f 1~ f N Feedback signals containing PDUs are sent sequentially to shortwave radio station A according to the set time slots, and each PDU carries the optimal frequency.

[0013] Furthermore, the duration of the dwell phase is set as follows: ,in, N The number of frequencies T A The duration of the probe signal sent by shortwave radio station A.

[0014] Furthermore, the reception frequency during the synchronization phase is: T A The set time slot for the available frequency feedback phase is the duration of the detection signal transmitted by shortwave radio station B. T B .

[0015] Furthermore, the set time slot for the optimal frequency feedback stage is: T B .

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The frequency selection method of this invention can determine a good communication frequency before communication between the two parties. Compared with the frequency set obtained by long-term prediction, this invention does not predict but actually probes and makes judgments based on the probe results, thereby selecting a workable or optimal frequency. The method provided by this invention can greatly improve the workability rate and communication efficiency.

[0017] 2. Compared to the constant switching and testing of a single frequency point, this invention can greatly save the time required to establish a communication link.

[0018] 3. The master station (shortwave radio station A) can obtain the optimal frequency in both directions and estimate the signal-to-noise ratio from the slave station (shortwave radio station B) to the master station (one-way). The slave station can obtain the optimal frequency and signal-to-noise ratio from the master to the slave (one-way). Compared with other existing technologies, it obtains more and more accurate information. Attached Figure Description

[0019] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the detection frequency-selective transmission format in this embodiment; Figure 2 This is a schematic diagram of the dwell phase and synchronization phase in this embodiment; Figure 3 This is a schematic diagram of the passable frequency feedback stage in this embodiment; Figure 4 The flowchart for selecting the optimal frequency in this embodiment is shown below; Figure 5 This is the average distance from the calculation point to the endpoint in this embodiment. Detailed Implementation

[0022] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0023] This embodiment provides a method for interactive channel scanning frequency selection for shortwave radio. Before formal communication, the sender sequentially sends probe signals of different frequencies to the receiver. The receiver estimates the signal-to-noise ratio (SNR) of the received probe signals to obtain the passable frequencies. The receiver then feeds back the passable frequencies to the sender. The sender analyzes the signals to obtain the first passable frequency, then selects all frequencies before the first passable frequency and sequentially sends the corresponding probe signals to the receiver. After receiving the signals, the receiver estimates the SNR and filters each channel based on all SNRs to obtain the optimal frequency. The receiver then feeds back the optimal frequency to the sender.

[0024] Furthermore, the transmitter is shortwave radio station A (hereinafter referred to as station A or A station), and the receiver is shortwave radio station B (hereinafter referred to as station B or B station). Both shortwave radio station A and shortwave radio station B are capable of receiving signals of any frequency, and can only receive signals of one frequency at a time, and cannot receive signals of multiple frequencies simultaneously.

[0025] Furthermore, the process of obtaining the available frequency includes a dwell phase, a synchronization phase, and an available frequency feedback phase; The dwell phase specifically refers to: shortwave radio station A transmitting frequencies sequentially before formal communication. f 1~ f N The detection signal was detected by shortwave radio station B at frequency [frequency not specified]. f 1~ f N Staying Duration (of which, N The number of frequencies T A (The duration of the probe signal transmitted by shortwave radio station A). After shortwave radio station B receives the first probe signal, it changes its receiving frequency to... T A Entering the synchronization phase; The synchronization phase specifically involves the following steps: After entering the synchronization phase, shortwave radio station B continues to receive detection signals until all frequencies of detection signals have been received. Shortwave radio station B then performs a signal-to-noise ratio (SNR) estimation on the received detection signals. If the SNR is -∞ dB, the corresponding frequency is not passable; otherwise, it is a passable frequency.

[0026] The available frequency feedback phase specifically involves the shortwave radio station B transmitting the frequency... f 1~ f N according to T B The duration (duration of the detection signal sent by shortwave radio station B) is used to send feedback signals containing PDUs to shortwave radio station A in sequence, and each PDU carries a passable frequency.

[0027] The process of obtaining the optimal frequency includes a detection phase and an optimal frequency feedback phase. The detection phase specifically involves: after parsing the PDU, shortwave radio A determines the frequency corresponding to when shortwave radio B enters the synchronization phase; shortwave radio A then sequentially processes the frequencies transmitted before that frequency according to... T A The shortwave radio station B transmits a corresponding detection signal for a certain duration. The shortwave radio station B estimates the signal-to-noise ratio of the received detection signal and, in conjunction with the signal-to-noise ratio obtained during the synchronization phase, selects the optimal frequency after comparison.

[0028] The optimal frequency feedback stage specifically involves the shortwave radio station B transmitting the frequency... f 1~ f N according to T B Feedback signals containing PDUs are sent sequentially to shortwave radio station A, each PDU carrying the optimal frequency.

[0029] It should be noted that the frequency f 1~ f N Let it be denoted as the frequency set The frequency set is agreed upon in advance by the sender and receiver. For example, the morning frequency set. Gather in the evening etc.

[0030] To enable those skilled in the art to more clearly understand the method of the present invention, the following examples are provided: Frequency selection model: Detection direction A (initiator) --> B (received call), in N Choose a passable or optimal frequency from the available frequencies. Assume that... N In each direction (A-->B / B-->A), there is at least one passable frequency, and the passable frequencies in the two directions can be different.

[0031] Symbol definition: Let set For a set of frequencies, The number of frequencies This indicates the communication frequency. Since it's bidirectional communication, the communication environments for A-->B and B-->A may differ. , These represent the directions A-->B and B-->A, respectively. The signal-to-noise ratio of the channel. (Used as symbols) and Let these represent the passable (or optimal) frequencies in the directions A-->B and B-->A, respectively. Clearly, in the case of bidirectional passability... , The signal-to-noise ratio corresponding to the passable (or optimal) frequency is denoted as... and Specifically, when there is no passable frequency between A and B, let , The same applies to the direction from B to A.

[0032] Frequency selection process: Based on actual needs, frequency selection can be divided into manageable frequency selection and optimal frequency selection. Manageable frequency selection refers to choosing a frequency from a given set that can be used for communication; it is not required that this frequency be the optimal frequency, as long as communication can be achieved. Optimal frequency selection refers to selecting the best frequency from a given set, which has the best communication performance, i.e., the highest signal-to-noise ratio.

[0033] The following is a set of four frequencies. Let's take an example to illustrate how to select the frequency (assuming the direction is A-->B). It is passable. Not accessible; B-->A direction It is passable. (Not passable). Frequency selection is as follows:Figure 1 Send in the specified format.

[0034] Frequency selection (dwelling phase) Station A transmits frequencies sequentially at any given time. The detection signal, and then the frequency received sequentially. The feedback signal repeats in this cycle. Station B sequentially operates at frequencies... The dwell time for each frequency is as follows: This duration ensures that a signal of the corresponding frequency is present within one dwell period. For example... Figure 1 As shown, station B is... When waiting, there must be a transmission frequency of The detected waveform is only in the A-->B direction. If B station is not reachable, it will not receive this signal. When B station is... During the waiting period, the frequency transmitted by station A was received. Upon detecting the waveform, station B immediately changes its receiving frequency to enter the synchronization phase.

[0035] Frequency selection (synchronization phase) B-stage from The synchronization phase continues until all frequency detection signals have been received, such as... Figure 2 As shown. Station B performs signal-to-noise ratio estimation on the received detection signal to obtain... Although the direction is A-->B It is not possible to connect, but this does not affect the signal-to-noise ratio estimation of station B in that time slot; it just means there is... Therefore, station B can determine which frequency is accessible during the synchronization phase; clearly, the accessible frequency here is... After the synchronization phase is completed, the system moves into the available frequency feedback phase.

[0036] It should be noted that the frequency selected by station B is the first frequency that can be used for communication. This frequency may not be the optimal one, but it will still be used. As a passable frequency.

[0037] Frequency selection is available (frequency feedback stage). After the synchronization phase, station B sends frequency feedback, transmitting the known usable frequencies to station A. Since station B doesn't know which frequency is usable from B to A, it uses different frequencies sequentially in different time slots for transmission. All transmitted waveforms are carried by the PDU. Regardless of the frequency of the signal received by station A, the passable frequency from A to B can be determined simply by analyzing its PDU. .like Figure 3 As shown.

[0038] It should be noted that at this time, station A can also perform signal-to-noise ratio estimation on the received signal to obtain the signal-to-noise ratio of each frequency channel from B to A. And select the optimal frequency from B to A. .

[0039] After the frequency selection is completed, station A will know the available frequencies. and optimal frequency And the signal-to-noise ratios from B to A; station B learns the available frequencies. And the signal-to-noise ratio of the A-->B section.

[0040] Optimal frequency selection: Optimal frequency selection requires comparing the signal-to-noise ratios of all frequencies and choosing the optimal one. Therefore, optimal frequency selection adds a detection stage and an optimal frequency feedback stage to the passable frequency selection. For example... Figure 4 As shown.

[0041] During the detection phase: After parsing the PDU, station A can determine the frequency from which station B entered the synchronization phase. Station B has performed signal-to-noise ratio estimation for frequencies after that index, but not for previous frequencies. Therefore, during the detection phase, station A only needs to transmit the frequency signal that has not yet been estimated. In the example above, station B starts from the frequency index... Entering the synchronization phase and already... Signal-to-noise ratio estimation was performed, therefore station A only needs to transmit frequencies sequentially during the detection phase. The detection waveform is sufficient.

[0042] After receiving the signal, station B performs signal-to-noise ratio estimation to obtain... Combined with the synchronization phase, we obtain The optimal frequency is selected by sorting all signal-to-noise ratios. , Optimal frequency feedback phase: Since station B does not know which frequency is available for transmission from B to A, it transmits on all frequencies, and all transmitted waveforms are carried by the PDU. Regardless of the frequency of the signal received by station A, the optimal frequency for switching from A to B can be determined simply by analyzing the PDU. .

[0043] After the optimal frequency selection was completed, station A learned the optimal frequency. and optimal frequency And the signal-to-noise ratios from B to A; station B obtains the optimal frequency. The signal-to-noise ratios of A-->B.

[0044] In this embodiment, it is particularly noteworthy that regardless of whether the passable frequency or the optimal frequency is selected, the process ends in nearly the same state, and station B is also aware of this. Ultimately, station A can only obtain the optimal frequency. If the optimal frequency for A-->B cannot be determined, and if there is no passable frequency in either direction (A-->B or B-->A), then station A will not receive a signal in the receiving segment, or station B will always be in the dwell phase.

[0045] To demonstrate the technical effectiveness of this invention, this embodiment analyzes the frequency selection time of the above examples: From the frequency selection process, we can see that there is no information transmission from A to B, only feedback information from B to A. Therefore, the A-->B probe waveform can be without a PDU, while the feedback waveform must have a PDU. Assume... There are frequencies that exist If there are two passable frequencies from A to B, then the probability that station B happens to be camped on a passable frequency when station A sends a probe waveform is: The probability of residing on a non-transparent frequency is .

[0046] When station B is stationed on a usable frequency, the current transmission period can enter synchronization. Therefore, the duration of the stationing phase plus the synchronization phase is... .

[0047] When station B is stationed on an unreachable frequency, it needs to wait for several stationing cycles (stationing cycle duration). To simplify the calculation, let it be Synchronization can only be achieved when the frequency is available. One passable frequency will The non-accessible frequencies are divided into Segments, each segment has an average of If there are no passable frequencies, the problem is transformed into calculating the average distance from the point to the destination. For example... Figure 5 As shown.

[0048] According to probability theory, the average distance is... That is, the average number of stay periods is The average duration of the frequency dwell phase plus the synchronization phase is... .

[0049] Taking into account different situations, we can obtain ; Frequency dwell time + average synchronization duration ; Available frequency feedback duration ; Average duration of the detection phase ; Optimal frequency feedback phase duration ; Precise Duration: In summary, when station A initiates detection at any time, the average time it takes for station A to complete one selection of a passable frequency is... The average time taken for station A to complete one optimal frequency selection. .

[0050] Actual duration: In practical applications, the waveforms in both directions are usually designed to be consistent, i.e. Then, station A completes one cycle of frequency selection with average time. The average time taken for station A to complete one optimal frequency selection. Table 1 gives the following information: different The time taken for the two frequency selection methods, assuming .

[0051] Table 1. Frequency selection time for different numbers of passable frequencies Number of passable frequencies n 1 2 3 4 5 6 7 8 9 10 Passable frequency selection time 101 52 36.33 29 25 22.67 21.29 20.5 20.11 20 Optimal frequency selection time 115.5 66.5 50.84 43.5 39.5 37.17 35.79 35 34.61 34.5 The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0052] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for short wave radio station interactive channel scanning frequency selection, characterized in that, Before formal communication, the sender sends different frequency probe signals to the receiver in turn, the receiver estimates the signal-to-noise ratio of the received probe signal, and then obtains the passable frequency, then the receiver feeds back the passable frequency to the sender, the sender analyzes to obtain the first passable frequency, then selects all frequencies before the first passable frequency and sends the corresponding probe signals to the receiver in turn, the receiver estimates the signal-to-noise ratio after receiving, and screens each channel according to all signal-to-noise ratios to obtain the optimal frequency, and then the receiver feeds back the optimal frequency to the sender.

2. The method for short wave radio station interactive channel scanning frequency selection according to claim 1, characterized in that, The sender is a short-wave radio station A, the receiver is a short-wave radio station B, the short-wave radio station A and the short-wave radio station B can receive signals of any frequency, and receive signals of one frequency at a time.

3. The method for short wave radio interactive channel scanning frequency selection according to claim 1, characterized in that, The process of obtaining the passable frequency includes a camping stage, a synchronization stage and a usable frequency feedback stage. The dwell phase specifically refers to: shortwave radio station A transmitting frequencies sequentially before formal communication. f 1~ f N The detection signal was detected by shortwave radio station B at frequency [frequency value missing]. f 1~ f N The station stays for a set duration. Once shortwave radio B receives the first detection signal, it changes its receiving frequency to enter the synchronization phase. The synchronization stage is specifically that the short-wave radio station B continues to receive the probe signal after entering the synchronization stage until all frequencies of the probe signal are received, the short-wave radio station B estimates the signal-to-noise ratio of the received probe signal, if the signal-to-noise ratio is -∞ dB, the corresponding frequency is not passable, otherwise, it is a passable frequency.

4. The method for short wave radio station interactive channel scanning frequency selection according to claim 3, characterized in that, The available frequency feedback stage is specifically that the short wave radio station B sends feedback signals containing PDU to the short wave radio station A in turn according to the set time slots, and the PDU all carry available frequencies. f 1~ f N The available frequency feedback stage is specifically that the short wave radio station B sends feedback signals containing PDU to the short wave radio station A in turn according to the set time slots, and the PDU all carry available frequencies.

5. The method for short wave radio interactive channel scanning frequency selection according to claim 1, characterized in that, The process of obtaining the optimal frequency includes a detection stage and an optimal frequency feedback stage. The detection stage is specifically that the short-wave radio station A analyzes the PDU to obtain the frequency corresponding to the synchronization stage when the short-wave radio station B enters the synchronization stage, the short-wave radio station A sends the corresponding probe signal to the frequency sent before the frequency in turn, the short-wave radio station B estimates the signal-to-noise ratio of the received probe signal, and selects the optimal frequency after comparing with the signal-to-noise ratio obtained in the synchronization stage.

6. The method for short wave radio station interactive channel scanning frequency selection according to claim 5, characterized in that, The optimal frequency feedback stage specifically includes: the short wave radio station B sends feedback signals containing PDU to the short wave radio station A in turn, and the PDU all carries the optimal frequency. f 1~ f N The short wave radio station B sends feedback signals containing PDU to the short wave radio station A in turn, and the PDU all carries the optimal frequency.

7. The method for short wave radio interactive channel scanning frequency selection according to claim 3, characterized in that, The set length of the residence phase is wherein, N is the number of frequencies, T A is the length of the probe signal transmitted by the short-wave radio station A.

8. The method for short wave radio station interactive channel scanning frequency selection of claim 4, wherein, The acceptance frequency of the synchronization stage is T A The set time slot of the available frequency feedback stage is the time length of the probe signal sent by the short wave radio station B T B .

9. The method for short wave radio interactive channel scanning frequency selection of claim 6, wherein, The set time slot of the optimal frequency feedback stage is T B .

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