Study On Interference Detection Technology Based On Signal Energy

The communication system suffers from the influence of electromagnetic wave interference,so anti-jamming technology emerges with the requirements.As the interference detection technology can provide reliable prior information for anti-jamming,the interference detection technology is one of the key technologies in the field of anti-jamming.Traditional interference detection technology of energy detection with simple algorithm procedure,can detect the interference signal more accurately under some certain conditions.However,the performance of the energy detection algorithm can not meet the requirements under much more lower signal to noise ratio(SNR).On the other hand,the algorithm can not accurately locate the specific location of interference.Therefore,the traditional energy detection algorithm needs to be improved to solve the problems discussed above.For the limits of the traditional energy detection algorithm,it is improved from two aspects.The traditional energy interference detection algorithm is combined with the stochastic resonance theory.The weak signal to be detected is enhanced by adding appropriate stochastic resonance noise to generate resonances.Compared with the traditional algorithm,it can detect interference in a lower SNR.In order to detect the specific location of the interference frequency,several improved frequency domain energy interference detection algorithms based on spread spectrum system are studied.For the interference detection in a low SNR,the main works of this thesis are concluded as follows:(1)The characteristics and categories of communication interference are introduced,and model five types of interference which is the theoretical basis for the interference detection.The traditional energy interference detection algorithm is briefly described and simulation analysis is given.(2)The traditional energy interference detection can not be judged accurately by the binary detection under the low SNR.The stochastic resonance theory is combined with the traditional energy detection algorithm to realize the correct binary detection of the interference signal under the lower SNR.Compared with the traditional algorithm,the proposed algorithm needs less number of detection points and the detection speed is faster.the simulation results show that the detection performance of the proposed algorithm is enhanced more than 3dB.(3)To locate the specific frequency points of the interference signal accurately in a low SNR,the traditional energy detection algorithm is extended to the frequency domain,and the energy of each frequency point of the signal is compared with the threshold value respectively to determine whether there is interference and combined with direct sequence spread spectrum,three frequency domain energy interference detection algorithms based on spread spectrum system are studied such as Consecutive Mean Excision algorithm(CME),Forward Consecutive Mean Excision algorithm(FCME),and double threshold FCME interference detection algorithm.These algorithms can effectively locate and suppress the specific interference frequency points.The influence of interference signals can be eliminated and the main user signals can be decoded correctly under low SNR.The performances of these algorithms for wideband interference are also studied.Finally,the simulated results for verification is presented.