CN-122026944-A - Method for eliminating broadband interference signal in spread spectrum communication system under non-homologous clock

CN122026944ACN 122026944 ACN122026944 ACN 122026944ACN-122026944-A

Abstract

The invention discloses a broadband interference signal elimination method in a spread spectrum communication system under a non-homologous clock. According to the method, the input signal is sampled and filtered, the cooperative interference signal is demodulated to obtain a corresponding data stream, the reconstructed interference signal is obtained by reconstructing the cooperative interference signal according to a modulation mode of the cooperative interference signal, non-homologous clock self-adaptive resampling is carried out on the reconstructed interference signal, and the problem of sampling point number change caused by the non-homologous clock is corrected. And finally, aligning and subtracting the sampling signal and the reconstructed interference signal after self-adaptive resampling to finish interference elimination. According to the invention, through carrying out non-homologous clock self-adaptive resampling after reconstructing the signal to compensate the jitter of the sampling point, the problem that the cooperative broadband interference signal is difficult to effectively eliminate in the non-homologous clock environment is solved, and the anti-interference capability and the anti-interception capability of the spread spectrum communication system are improved.

Inventors

HE DONGXUAN
LIU RENJIE
WANG HUA
ZHAO HONGYE

Assignees

北京理工大学

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (8)

1. A method for canceling a wideband jammer in a spread spectrum communication system under a non-homologous clock, the method comprising: step S1, sampling and filtering the superimposed signal of the interference signal and the spread spectrum communication signal to obtain filtered data; step S2, demodulating the filtered data to obtain a demodulated data stream, and obtaining the actual sampling point number of the modulation symbols in the cooperative interference signal ; S3, reconstructing the demodulated data stream according to a system combined with an interference signal to obtain a reconstructed interference signal, wherein one modulation symbol in the reconstructed interference signal comprises a set n sampling points; Step S4, performing non-homologous clock self-adaptive resampling on the reconstructed interference signal, so as to adjust the number of sampling points contained in the modulation symbol in the reconstructed interference signal to be equal to the number of actual sampling points Consistent, rather than always remaining at n; And S5, aligning and subtracting the filtered data obtained in the step S1 and the reconstructed interference signal obtained after the self-adaptive resampling in the step S4, and completing interference elimination.
2. The method of claim 1, wherein the step S2 is to obtain the actual number of sampling points of the modulation symbols in the cooperative interference signal The method comprises the following steps: the receiving device clock is adopted to count the interval between two adjacent effective enabling signals in the enabling signals which are generated in the demodulation process and are used for indicating whether the modulation symbols are synthesized, and the counted value is the actual sampling point number of the modulation symbols 。
3. The method according to claim 2, wherein said step S2 obtains the actual number of sampling points Then, the number of the actual sampling points is directly calculated As the timing synchronization signal content, the timing synchronization signal is provided for the non-homologous clock self-adaptive resampling step or the actual sampling point number is compared And (3) generating timing synchronous signals representing different differences from the differences of n, and providing the timing synchronous signals for the non-homologous clock self-adaptive resampling step.
4. The method of claim 1, wherein in the step S4, the number of sampling points included in the modulation symbol in the reconstructed interference signal is adjusted to be equal to the actual number of sampling points The consistency is specifically as follows: Storing the reconstructed interference signal to be resampled in a reconstructed interference signal buffer module; the redundant sampling points are skipped by adjusting the data address read from the reconstructed interference signal buffer module, or the missing sampling points are compensated by repeatedly reading one sampling point.
5. The method of claim 1, wherein the step of skipping redundant sampling points by adjusting the data address read from the reconstructed interference signal buffer module or by repeatedly reading one sampling point to compensate for missing sampling points is specifically: If the actual sampling point number of the current modulation symbol If n-1 is, at the next moment, reading the data address of the reconstructed interference signal buffer module, adding 2, and skipping redundant sampling points; If the actual sampling point number of the current modulation symbol If n is equal, reading the data address of the reconstructed interference signal buffer module at the next moment, increasing by 1, and normally reading the data; If the actual sampling point number of the current modulation symbol And if n+1, reading the data address of the reconstructed interference signal buffer module at the next moment, and reading the reconstructed interference signal data of the same address twice to compensate the missing sampling point.
6. The device is characterized by comprising a sampling and filtering unit, a broadband interference signal demodulation unit, a broadband interference signal reconstruction unit and an adaptive resampling and interference elimination unit; The sampling and filtering unit is used for sampling and filtering the superimposed signal of the interference signal and the spread spectrum communication signal to obtain filtered data; the broadband interference signal demodulation unit is used for demodulating the filtered data to obtain a demodulated data stream, transmitting the demodulated data stream to the broadband interference signal reconstruction unit and the self-adaptive resampling and interference elimination unit, and obtaining the actual sampling point number of the modulation symbols in the cooperative interference signal Generating an indication of the actual number of sampling points Is sent to the adaptive resampling and interference cancellation unit; The broadband interference signal reconstruction unit is used for reconstructing the demodulated data stream according to a system which is combined with an interference signal, obtaining a reconstructed interference signal, and sending the reconstructed interference signal to the self-adaptive resampling and interference elimination unit; The self-adaptive resampling and interference eliminating unit is used for carrying out non-homologous clock self-adaptive resampling on the reconstructed interference signal so as to adjust the number of sampling points contained in the modulation symbol in the reconstructed interference signal to be equal to the number of actual sampling points And (3) obtaining the adaptively resampled reconstructed interference signal instead of always keeping the same as n, and carrying out alignment subtraction on the filtered data and the adaptively resampled reconstructed interference signal to finish interference elimination.
7. The apparatus of claim 6, wherein the broadband interference signal demodulation unit obtains an actual number of sampling points of modulation symbols in the cooperative interference signal The method comprises the following steps: the receiving device clock is adopted to count the interval between two adjacent effective enabling signals in the enabling signals which are generated in the demodulation process and are used for indicating whether the modulation symbols are synthesized, and the counted value is the actual sampling point number of the modulation symbols ; Number of actual sampling points Provided as a timing synchronization signal content to an adaptive resampling and interference cancellation unit, or first comparing the actual number of sampling points And generating timing synchronous signals representing different differences from the difference of the number n of the set sampling points and providing the timing synchronous signals for the self-adaptive resampling and interference elimination unit.
8. The apparatus of claim 6, wherein the adaptive resampling and interference cancellation unit comprises a reconstructed interference signal buffer module, a non-homologous clock adaptive resampling module, a data alignment module, and an interference cancellation module; The reconstructed interference signal buffer module is used for storing the reconstructed interference signal from the broadband interference signal reconstruction unit and waiting for resampling; The non-homologous clock self-adaptive resampling module is used for performing non-homologous clock self-adaptive resampling on the reconstructed interference signal stored by the reconstructed interference signal buffer module: If the timing synchronization signal indicates the actual number of sampling points of the current modulation symbol If n-1 is, at the next moment, reading the data address of the reconstructed interference signal buffer module, adding 2, and skipping redundant sampling points; If the timing synchronization signal indicates the actual number of sampling points of the current modulation symbol If n is equal, reading the data address of the reconstructed interference signal buffer module at the next moment, increasing by 1, and normally reading the data; If the timing synchronization signal indicates the actual number of sampling points of the current modulation symbol If n+1, reading the data address of the reconstructed interference signal buffer module at the next moment, keeping unchanged, and compensating the missing sampling point; the data alignment module and the interference elimination module are used for carrying out alignment subtraction on the filtered data obtained by the sampling and filtering unit and the reconstructed interference signal after self-adaptive resampling so as to complete interference elimination.

Description

Method for eliminating broadband interference signal in spread spectrum communication system under non-homologous clock Technical Field The invention relates to the technical field of spread spectrum communication, in particular to a method and a device for eliminating broadband interference signals in a spread spectrum communication system under a non-homologous clock. Background Spread spectrum communication is widely used in various fields due to its good anti-interference and anti-interception properties. However, as communication environments become more complex, spread spectrum signals are severely affected by wideband interference, resulting in degradation of system performance. Meanwhile, the traditional frequency domain filtering is difficult to effectively distinguish the interference signal from the useful signal, so that the influence of broadband interference on the spread spectrum signal cannot be effectively processed. At present, related researches on broadband interference elimination of spread spectrum signals mainly focus on an interference elimination method under the condition of a homologous clock, and lack of an effective scheme for time domain interference elimination under the condition of a non-homologous clock. Under the condition of non-homologous clock, the crystal oscillator frequency offset and the sampling clock offset make the traditional signal reconstruction and signal alignment methods difficult to apply. In particular, due to the crystal oscillator frequency offset and the sampling clock offset, the number of sampling points of each symbol may not be consistent with the ideal sampling condition in practical situations, so that the difficulty of signal reconstruction and signal alignment is increased. If the interfering signal is a cooperative signal of a known frame structure, wideband signal interference can be eliminated by an adaptive resampling time domain interference cancellation method. Based on this, the present invention has studied a broadband interference signal cancellation method in a spread spectrum communication system under a non-homologous clock. Disclosure of Invention In view of the above, the invention provides a method and a device for eliminating broadband interference signals in a spread spectrum communication system under a non-homologous clock, which solve the problem that cooperative broadband interference signals are difficult to effectively eliminate in a non-homologous clock environment by performing self-adaptive resampling of the non-homologous clock after reconstructing signals to compensate sampling point jitter, and improve the anti-interference capability and anti-interception capability of the spread spectrum communication system. The present invention is so implemented as to solve the above-mentioned technical problems. A method of wideband interference signal cancellation in a non-homologous clock under-spread-spectrum communication system, the method comprising: step S1, sampling and filtering the superimposed signal of the interference signal and the spread spectrum communication signal to obtain filtered data; step S2, demodulating the filtered data to obtain a demodulated data stream, and obtaining the actual sampling point number of the modulation symbols in the cooperative interference signal ; S3, reconstructing the demodulated data stream according to a system combined with an interference signal to obtain a reconstructed interference signal, wherein one modulation symbol in the reconstructed interference signal comprises a set n sampling points; Step S4, performing non-homologous clock self-adaptive resampling on the reconstructed interference signal, so as to adjust the number of sampling points contained in the modulation symbol in the reconstructed interference signal to be equal to the number of actual sampling points Consistent, rather than always remaining at n; And S5, aligning and subtracting the filtered data obtained in the step S1 and the reconstructed interference signal obtained after the self-adaptive resampling in the step S4, and completing interference elimination. Preferably, in step S2, the actual number of sampling points of the modulation symbols in the cooperative interference signal is obtainedThe method comprises the following steps: the receiving device clock is adopted to count the interval between two adjacent effective enabling signals in the enabling signals which are generated in the demodulation process and are used for indicating whether the modulation symbols are synthesized, and the counted value is the actual sampling point number of the modulation symbols 。 Preferably, the step S2 obtains the actual number of sampling pointsThen, the number of the actual sampling points is directly calculatedAs the timing synchronization signal content, the timing synchronization signal is provided for the non-homologous clock self-adaptive resampling step or the actual sampling point number is comparedAnd