Short-wave full-frequency staring-distributed cooperative frequency, channel and link measurement method

Abstract

The embodiment of the invention provides a short-wave full-frequency staring-distributed cooperative frequency, channel and link measurement method. The method is applied to the field of short-wave measurement, and comprises the following steps: performing multi-phase filtering on a received broadband signal to obtain a multi-channel signal; determining signal power and noise power of the multi-channel signal, and determining frequency availability according to the signal power and the noise power; selecting an available frequency according to the frequency availability, measuring through a linear frequency modulation signal transmitted in a channel to obtain a channel characteristic parameter, and determining the channel availability according to the channel characteristic parameter; signals with different waveforms are transmitted in a specified link, link characteristics are obtained through measurement, and link availability is determined according to the link characteristics; the frequency availability, the channel availability and the link availability are subjected to statistical analysis to obtain a statistical analysis result, data support is provided for multi-link cooperative transmission strategy adjustment and link access decision, and the efficiency and reliability of short-wave communication are improved.

Description

Technical Field

[0001] This application relates to the field of shortwave measurement, and in particular to a shortwave full-frequency staring-distributed cooperative frequency, channel, and link measurement method. Background Technology

[0002] In the complex propagation environment formed by the ionosphere and troposphere, shortwave beyond-line-of-sight link transmission faces many challenges such as signal attenuation, multipath interference, and channel time-varying. In particular, for remote mobile platforms, the dynamic changes in their positions further exacerbate the difficulty of maintaining link stability.

[0003] To achieve efficient and reliable beyond-line-of-sight communication, it is urgent to adopt a multi-link collaborative transmission method. This involves integrating communication link resources from different frequency bands and multiple stations, and dynamically adjusting transmission strategies to cope with link uncertainties in complex environments. Summary of the Invention

[0004] This application provides a shortwave full-frequency staring-distributed cooperative frequency, channel, and link measurement method to address the shortcomings of existing technologies that lack multi-dimensional unified measurement. The method includes:

[0005] The received broadband signal is subjected to polyphase filtering to obtain a multi-channel signal;

[0006] Determine the signal power and noise power of the multi-channel signal, and determine the frequency availability based on the signal power and noise power;

[0007] Available frequencies are selected based on frequency availability. Channel characteristic parameters are measured by transmitting linear frequency modulated signals through the channel, and channel availability is determined based on these parameters.

[0008] Transmit signals of different waveforms through a specified link, measure the link characteristics, and determine the link availability based on the link characteristics.

[0009] Statistical analysis was performed on frequency availability, channel availability, and link availability to obtain the statistical analysis results.

[0010] Optionally, the step of performing polyphase filtering on the received broadband signal to obtain a multi-channel signal includes:

[0011] The received broadband signal is converted from analog to digital to obtain a broadband digital signal;

[0012] Two-stage polyphase filtering is performed on the broadband digital signal to obtain a multi-channel narrowband signal.

[0013] Optionally, determining the signal power and noise power of the multi-channel signal, and determining frequency availability based on the signal power and noise power, includes:

[0014] Parallel processing of multi-channel signals, performing fast Fourier transform, yields the power spectrum of the broadband signal;

[0015] Calculate the signal power and noise power of different frequency bands based on the broadband signal power spectrum;

[0016] For a given frequency band, the signal power and noise power are numerically compared, and the occupancy of the frequency band is determined based on the comparison results.

[0017] The frequency availability of the frequency band is determined based on its occupancy status.

[0018] Optionally, the step of selecting an available frequency based on frequency availability, by measuring channel characteristic parameters through a linear frequency modulated signal transmitted in the channel, and determining channel availability based on the channel characteristic parameters, includes:

[0019] Select the frequency with the highest frequency availability as the available frequency;

[0020] Transmit linear frequency modulated (LFM) signals on channels corresponding to available frequencies, and obtain channel characteristic parameters by analyzing and processing the transmitted LFM signals.

[0021] Channel availability is determined based on channel characteristic parameters.

[0022] Optionally, the process of analyzing and processing the transmitted linear frequency modulated signal to obtain channel characteristic parameters includes:

[0023] Using linear frequency modulated signal matched filtering, determine whether the peak value of the matched filter is greater than a preset threshold;

[0024] When the matched filter peak value is greater than a preset threshold, the channel scattering function is calculated to obtain the channel characteristic parameters. The scattering function satisfies the following formula:

[0025]

[0026] in, The autocorrelation function representing the channel impulse response. Indicates time delay. Indicates time offset. This indicates Doppler.

[0027] Optionally, the channel characteristic parameters include: signal-to-noise ratio, multipath number, multipath delay, maximum intra-path delay spread, Doppler offset, and maximum intra-path Doppler spread. Determining channel availability based on the channel characteristic parameters includes:

[0028] Determine signal-to-noise ratio availability based on signal-to-noise ratio;

[0029] Determine multipath availability based on the number of multipaths;

[0030] Determine multipath delay availability based on multipath delay;

[0031] Determine delay spread availability based on maximum intra-path delay spread;

[0032] Determine the availability of Doppler offset based on Doppler offset;

[0033] Doppler spread availability is determined based on the maximum diameter Doppler spread.

[0034] Channel availability is determined based on signal-to-noise ratio availability, multipath availability, multipath delay availability, delay spread availability, Doppler offset availability, and Doppler spread availability.

[0035] Optionally, the step of transmitting signals of different waveforms on a specified link, measuring the link characteristics, and determining link availability based on the link characteristics includes:

[0036] Within a specified link, signals of various different waveforms are selected and transmitted sequentially.

[0037] During signal transmission, characteristic measurements are performed on a specified link to obtain the link characteristic parameters corresponding to each waveform signal transmission.

[0038] Based on the measured link characteristic parameters and according to the preset link availability evaluation criteria, the availability of the specified link is determined.

[0039] This application provides a shortwave full-frequency staring-distributed cooperative frequency, channel, and link measurement method. This method obtains multi-channel signals by performing polyphase filtering on the received broadband signal; determines the signal power and noise power of the multi-channel signals, and determines frequency availability based on the signal power and noise power; selects an available frequency based on frequency availability; measures channel characteristic parameters by transmitting linear frequency modulated signals through the channel, and determines channel availability based on the channel characteristic parameters; transmits signals of different waveforms through a designated link, measures link characteristics, and determines link availability based on the link characteristics; and performs statistical analysis on frequency availability, channel availability, and link availability to obtain statistical analysis results. This provides data support for adjusting multi-link cooperative transmission strategies and making link access decisions, thereby improving the efficiency and reliability of shortwave communication. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0041] Figure 1 A flowchart illustrating the shortwave full-frequency staring-distributed cooperative frequency, channel, and link measurement method provided in this application embodiment;

[0042] Figure 2 Measured graphs of shortwave frequency availability provided in embodiments of this application;

[0043] Figure 3 This is a measured diagram of shortwave channel availability provided in an embodiment of this application;

[0044] Figure 4 The measured diagram shows the availability of the shortwave link provided in the embodiments of this application.

[0045] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0047] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0048] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0049] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0050] Figure 1 This is a flowchart illustrating the shortwave full-frequency staring-distributed cooperative frequency, channel, and link measurement method provided in an embodiment of this application. Figure 1 As shown, the shortwave full-frequency staring-distributed cooperative frequency, channel, and link measurement method provided in this embodiment includes:

[0051] S1: Perform polyphase filtering on the received broadband signal to obtain a multi-channel signal.

[0052] Understandably, by receiving broadband signals through a receiving device and digitally channelizing them through a polyphase filter, multi-channel signals are obtained, enabling full-frequency staring.

[0053] Specifically, the received broadband signal is converted from analog to digital to obtain a broadband digital signal; the broadband digital signal is then subjected to two-stage multiphase filtering to obtain a multi-channel narrowband signal.

[0054] For example, the first stage uses an 8-phase multiphase filter bank to coarsely divide the high-speed sampling signal into 8 parallel low-speed coarse channels. The second stage uses a 32-phase multiphase filter bank. Each coarse channel output from the first stage is connected to a 32-phase multiphase filter bank to decompose each coarse channel into 32 fine channels. All the fine channels output from the second stage are integrated in frequency order to obtain the final 256-channel narrowband signal.

[0055] S2: Determine the signal power and noise power of the multi-channel signal, and determine the frequency availability based on the signal power and noise power.

[0056] Specifically, the system processes multi-channel signals in parallel, performs a fast Fourier transform to obtain a broadband signal power spectrum, calculates the signal power and noise power of different frequency bands based on the broadband signal power spectrum, performs a numerical comparison of the signal power and noise power for a specified frequency band, determines the occupancy status of the frequency band based on the comparison results, and determines the frequency availability of the frequency band based on the occupancy status of the frequency band.

[0057] More specifically, multi-channel signals are processed in parallel, and a Fast Fourier Transform is performed, satisfying the following formula:

[0058]

[0059] in, For the first Each time-domain sampling point For the number of points in the Fast Fourier Transform, For the first One frequency point.

[0060] For example, the data per second undergoes 46 Fast Fourier Transforms and 46 power spectral averages to obtain the average power of the 1-second signal:

[0061]

[0062] Furthermore, power values ​​at different frequency precisions were calculated to obtain the power of the 200 / 3000 / 6000 / 12000 / 24000Hz frequency bands. Taking the 3000Hz bandwidth as an example, its signal power spectrum... .

[0063] Furthermore, the noise floor is calculated segment by segment. The 3.072MHz bandwidth is divided into 8 segments for parallel noise floor calculation, each segment having a bandwidth of 384kHz. Taking the 3kHz resolution noise floor as an example, the power of all 3kHz signals in the 384kHz bandwidth is sorted, and the smallest 10% of power values ​​(at least 3 values ​​are averaged) are used as the current 384kHz bandwidth noise floor.

[0064] Furthermore, for a given frequency band, if its power is 10dB higher than the noise floor, it is considered to be occupied; otherwise, it is not occupied.

[0065] Furthermore, occupancy is calculated once per second, resulting in 60 occupancy statuses per minute. The frequency availability per minute = total number of idle times per minute / 60.

[0066] Understandably, by measuring frequency availability, it is possible to identify available frequency ranges in the current environment where there is no significant interference.

[0067] S3: Select an available frequency based on frequency availability. Obtain channel characteristic parameters by measuring the linear frequency modulated signal transmitted in the channel, and determine the channel availability based on the channel characteristic parameters.

[0068] Specifically, it includes the following steps:

[0069] S31: Select the frequency with the highest frequency availability as the available frequency.

[0070] For example, within the range of highest available frequencies, the frequency with the highest minute availability is selected as the operating frequency, and a linear frequency modulation signal is transmitted and received accordingly.

[0071] S32: Transmit a linear frequency modulated signal on the channel corresponding to the available frequency, and obtain the channel characteristic parameters by analyzing and processing the transmitted linear frequency modulated signal.

[0072] Specifically, by analyzing and processing the transmitted linear frequency modulated signal, channel characteristic parameters are obtained, including:

[0073] The linear frequency modulated signal is matched and filtered, and a dynamic threshold is set to mean + 4 × standard deviation. If the peak value of the matched filter is greater than the threshold, the detection is successful; otherwise, the detection fails.

[0074] If detection is successful, the channel scattering function is calculated to obtain the channel characteristic parameters. The scattering function satisfies the following formula:

[0075]

[0076] in, The autocorrelation function representing the channel impulse response. Indicates time delay. Indicates time offset. This indicates Doppler.

[0077] S33: Determine the availability of the channel based on the channel characteristic parameters.

[0078] The channel characteristic parameters include: signal-to-noise ratio, number of multipaths, multipath delay, maximum intra-path delay spread, Doppler offset, and maximum intra-path Doppler spread.

[0079] Specifically, signal-to-noise ratio (SNR) availability is determined based on the signal-to-noise ratio (SNR); multipath availability is determined based on the number of multipath paths; multipath delay availability is determined based on the multipath delay; delay spread availability is determined based on the maximum intra-path delay spread; Doppler offset availability is determined based on the Doppler offset; Doppler spread availability is determined based on the maximum intra-path Doppler spread; and channel availability is determined based on SNR availability, multipath availability, multipath delay availability, delay spread availability, Doppler offset availability, and Doppler spread availability.

[0080] In an optional embodiment, if the detection is successful, the channel detection availability = 1; if the detection fails, the channel detection availability = 0.

[0081] When the signal-to-noise ratio (SNR) is ≥10dB, the channel SNR availability = 1; for every 1dB decrease, the channel SNR availability decreases by 0.05; when the SNR is ≤-10dB, the channel SNR availability drops to 0; that is: channel SNR availability = min(1, max(0, 1 + (SNR - 10) × 0.05));

[0082] When the number of multipaths is 1, the channel multipath availability is 1; for every additional multipath, the channel multipath availability decreases by 0.2; when the number of multipaths is ≥6, the channel multipath availability drops to 0. That is: Channel multipath availability = max(0, 1 - (number of multipaths - 1) × 0.2);

[0083] When the multipath delay is ≤0.1ms, the channel multipath delay availability = 1; for every 1ms increase, the channel multipath delay availability decreases by 0.2; when the multipath delay is ≥5.1ms, the channel multipath delay availability drops to 0. That is: Channel multipath delay availability = min(1, max(0, 1 - (multipath delay - 0.1) × 0.2));

[0084] If the maximum path delay spread is ≤0.1ms, the channel delay spread availability = 1; for every 0.1ms increase, the channel delay spread availability decreases by 0.1; when the maximum path delay spread is ≥1.1ms, the channel delay spread availability drops to 0. That is: Channel delay spread availability = min(1, max(0, 1 - (maximum path delay spread - 0.1)));

[0085] For Doppler offset ≤ 0.1Hz, channel Doppler offset availability = 1; for every 1Hz increase, channel Doppler offset availability decreases by 0.2; when Doppler offset ≥ 5.1Hz, channel Doppler offset availability drops to 0. That is: Channel Doppler offset availability = min(1, max(0, 1 - (Doppler offset - 0.1) × 0.2));

[0086] When the maximum diameter Doppler spread is ≤0.1Hz, the channel Doppler spread availability = 1; for every 0.1Hz increase, the channel Doppler spread availability decreases by 0.1; when the maximum diameter Doppler spread is ≥1.1Hz, the channel Doppler spread availability drops to 0. That is: Channel Doppler spread availability = min(1, max(0, 1 - (maximum diameter Doppler spread - 0.1)));

[0087] Channel availability = Channel detection availability × (Channel signal-to-noise ratio availability + Channel multipath availability + Channel multipath delay availability + Channel delay spread availability + Channel Doppler offset availability + Channel Doppler spread availability) / 6.

[0088] Channel availability is calculated quantitatively from a single measurement result, and the average channel availability over ten minutes is obtained. Channel availability ≤ 0.25 is considered a poor channel, channel availability ≥ 0.75 is considered a good channel, and the rest are considered medium channels.

[0089] Understandably, by monitoring and analyzing channel characteristic parameters in real time, we can promptly grasp the time-varying patterns of the channel, providing a basis for subsequent link adjustments and signal optimization.

[0090] S4: Transmit signals of different waveforms on a specified link, measure the link characteristics, and determine the link availability based on the link characteristics.

[0091] The transmitted signals can be of different waveforms, such as frequency-shifted chirp modulated signals, multi-carrier signals, and single-carrier signals. Link characteristics include: synchronization rate, frame error rate, and bit error rate.

[0092] Understandably, link availability measurement aims to assess the actual communication capability of a link under different frequency and channel combinations, and to determine whether it can meet the communication needs of a remote mobile platform.

[0093] Specifically, within a designated link, signals of various waveforms are selected and transmitted sequentially; during signal transmission, the characteristics of the designated link are measured to obtain the link characteristic parameters corresponding to the transmission of each waveform signal; based on the measured link characteristic parameters and according to the preset link availability evaluation criteria, the availability of the designated link is determined.

[0094] In an optional embodiment, single-link availability measurement includes:

[0095] A fixed transceiver transmits fixed frames of data for a specific waveform signal, and the receiver decodes them within a predetermined time.

[0096] The average synchronization rate, frame error rate, and bit error rate over a ten-minute period are used as the ten-minute single-link availability.

[0097] In multi-link measurement, multiple stations simultaneously receive a single transmitted signal and transmit the received data to the fusion center to complete multi-link fusion.

[0098] Multi-link fusion is divided into different diversity methods based on the spatial distribution of stations, including:

[0099] Polarization diversity: The antennas of the two receiving stations are arranged in a cross shape to achieve separation of O-wave and X-wave;

[0100] Local diversity: Multiple receiving stations are deployed in adjacent areas, with antenna distances of less than 10 kilometers;

[0101] Regional diversity: Multiple receiving stations are distributed at large intervals, ranging from 10 to 500 kilometers;

[0102] Wide-area diversity: Multiple receiving stations are deployed in different locations, with an antenna spacing of more than 500 kilometers.

[0103] Multi-link availability measurement includes:

[0104] For a given waveform signal, one transmitter transmits fixed frame data, and multiple receivers receive it simultaneously.

[0105] Multiple receivers transmit the received data back to the fusion center in real time via the Internet, and the fusion center completes the signal fusion and decoding;

[0106] The average synchronization rate, frame error rate, and bit error rate of the fusion results within a ten-minute period are used as the ten-minute multi-link availability.

[0107] Links with availability ≤0.25 are considered poor links, those with availability ≥0.75 are considered good links, and the rest are considered medium links. When a link is determined to be poor, the current link should be replaced with a transmission waveform that offers higher reliability. When a link is determined to be good, a waveform with a higher transmission rate can be used.

[0108] Different waveforms have different bandwidths and frame structures, resulting in varying anti-fading capabilities and enabling different transmission rates. Channel capacity is represented by the number of bytes of information successfully transmitted per minute; the higher the channel capacity, the better the matching between the current waveform link and the channel.

[0109] Different waveform link availability requirements dictate different channel availability requirements, and different channel availability levels can achieve different waveform link availability levels. However, under the same channel availability, there is an optimal waveform with the highest channel capacity, enabling the most efficient transmission.

[0110] S5: Perform statistical analysis on frequency availability, channel availability, and link availability to obtain the statistical analysis results.

[0111] Understandably, the obtained frequency availability, channel availability, and link availability data are transmitted to the data center for integration and analysis. Redundant information and abnormal data are removed, and key information reflecting the true state of beyond-line-of-sight links is extracted to provide data support for link transmission decisions.

[0112] Figure 2 A measured graph showing the availability of shortwave frequencies provided in an embodiment of this application. (See attached graph.) Figure 2 As shown, the horizontal axis represents time, the vertical axis represents channels, and the color indicates frequency availability. The brighter the color, the higher the frequency availability; the darker the color, the lower the frequency availability.

[0113] Figure 3 The image shows a measured diagram of shortwave channel availability provided in an embodiment of this application. Figure 3 As shown, the three-dimensional graph represents the scattering function, and the two-dimensional graphs represent the time delay power spectrum and the Doppler power spectrum, respectively, reflecting the multipath, time delay, and Doppler characteristics of the shortwave channel. The table data represents the channel characteristic values ​​measured in real time.

[0114] Figure 4 The above is a measured diagram of shortwave link availability provided in an embodiment of this application. Figure 4 As shown, the link domain measurement results include: time, frequency, encoding method, as well as the measured number of synchronizations, number of correct unpackings, and bit error rate, thereby obtaining the link availability.

[0115] This embodiment provides a shortwave full-frequency staring-distributed collaborative frequency, channel, and link measurement method. This method achieves full-frequency staring by performing polyphase filtering on the received broadband signal to obtain multi-channel signals; determining the signal power and noise power of the multi-channel signals, and determining frequency availability based on the signal power and noise power; selecting available frequencies based on frequency availability; measuring channel characteristic parameters by transmitting linear frequency modulated signals through the channel, and determining channel availability based on the channel characteristic parameters; transmitting signals of different waveforms through a designated link, measuring link characteristics, and determining link availability based on the link characteristics; achieving distributed collaboration at the local, regional, and wide-area levels through unified measurement of frequency, channel, and link availability across multiple channels; and analyzing and integrating measurement data from different sources and dimensions in a data center to provide data support for adjusting multi-link collaborative transmission strategies and making link access decisions, thus contributing to efficient and reliable shortwave communication.

[0116] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0117] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A shortwave full-frequency staring-distributed cooperative frequency, channel, and link measurement method, characterized in that, The method includes: The received broadband signal is subjected to polyphase filtering to obtain a multi-channel signal; Determine the signal power and noise power of the multi-channel signal, and determine the frequency availability based on the signal power and noise power; Available frequencies are selected based on frequency availability. Channel characteristic parameters are measured by transmitting linear frequency modulated signals through the channel, and channel availability is determined based on these parameters. Transmit signals of different waveforms through a specified link, measure the link characteristics, and determine the link availability based on the link characteristics. Statistical analysis was performed on frequency availability, channel availability, and link availability to obtain the statistical analysis results.

2. The method according to claim 1, characterized in that, The process of performing polyphase filtering on the received broadband signal to obtain a multi-channel signal includes: The received broadband signal is converted from analog to digital to obtain a broadband digital signal; Two-stage polyphase filtering is performed on the broadband digital signal to obtain a multi-channel narrowband signal.

3. The method according to claim 1, characterized in that, The determination of the signal power and noise power of the multi-channel signal, and the determination of frequency availability based on the signal power and noise power, includes: Parallel processing of multi-channel signals, performing fast Fourier transform, yields the power spectrum of the broadband signal; Calculate the signal power and noise power of different frequency bands based on the broadband signal power spectrum; For a given frequency band, the signal power and noise power are numerically compared, and the occupancy of the frequency band is determined based on the comparison results. The frequency availability of the frequency band is determined based on its occupancy status.

4. The method according to claim 3, characterized in that, The step of selecting an available frequency based on frequency availability involves measuring channel characteristic parameters using a linear frequency modulated signal transmitted through the channel, and determining channel availability based on these parameters. Select the frequency with the highest frequency availability as the available frequency; Transmit linear frequency modulated (LFM) signals on channels corresponding to available frequencies, and obtain channel characteristic parameters by analyzing and processing the transmitted LFM signals. Channel availability is determined based on channel characteristic parameters.

5. The method according to claim 4, characterized in that, The process of analyzing and processing the transmitted linear frequency modulated signal to obtain channel characteristic parameters includes: Using linear frequency modulated signal matched filtering, determine whether the peak value of the matched filter is greater than a preset threshold; When the matched filter peak value is greater than a preset threshold, the channel scattering function is calculated to obtain the channel characteristic parameters. The scattering function satisfies the following formula: ； in, The autocorrelation function representing the channel impulse response. Indicates time delay. Indicates time offset. This indicates Doppler.

6. The method according to claim 5, characterized in that, The channel characteristic parameters include: signal-to-noise ratio, multipath number, multipath delay, maximum intra-path delay spread, Doppler offset, and maximum intra-path Doppler spread. Determining channel availability based on these channel characteristic parameters includes: Determine signal-to-noise ratio availability based on signal-to-noise ratio; Determine multipath availability based on the number of multipaths; Determine multipath delay availability based on multipath delay; Determine delay spread availability based on maximum intra-path delay spread; Determine the availability of Doppler offset based on Doppler offset; Doppler spread availability is determined based on the maximum diameter Doppler spread. Channel availability is determined based on signal-to-noise ratio availability, multipath availability, multipath delay availability, delay spread availability, Doppler offset availability, and Doppler spread availability.

7. The method according to claim 1, characterized in that, The process of transmitting signals of different waveforms on a designated link, measuring link characteristics, and determining link availability based on those characteristics includes: Within a specified link, signals of various different waveforms are selected and transmitted sequentially. During signal transmission, characteristic measurements are performed on a specified link to obtain the link characteristic parameters corresponding to each waveform signal transmission. Based on the measured link characteristic parameters and according to the preset link availability evaluation criteria, the availability of the specified link is determined.

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