Research On Anti-jamming Technology Of Subset-based Coherent Fast Frequency Hopping Systems

Fast Frequency Hopping(FFH)system with strong anti-jamming capability,transmits a modulation symbol via multiple hopping frequencies.However,the traditional FFH/MFSK system has low spectrum efficiency and has non-coherent combining loss.Therefore,this paper studies the Subset-based Coherent Fast Frequency Hopping(S-CFFH)system.The S-CFFH system with high spectral efficiency provides a feasible scheme for solving the channel estimation problem in the traditional FFH system.Therefore,it is necessary to study the S-CFFH system.This paper mainly studies the anti-jamming technology of S-CFFH system,including jamming detection technology,jamming suppression technology,anti-jamming combining technology and jamming cancellation technology.This paper also studies the S-CFFH system combined with spatial modulation(SM),which can further improve the spectral efficiency,and then studies anti-jamming technology of S-CFFH/SM.The specific contents are as follows:The first part introduces the research background and significance of the paper,and the research status of anti-jamming technology of fast frequency hopping system and spatial modulation technology.The second part studies the jamming detection algorithm in S-CFFH system.An adaptive jamming detection algorithm combining the advantages of Constant False Alarm Rate(CFAR)jamming detection and Minimum Error Probability(MEP)jamming detection algorithm is proposed,and CFAR jamming detection is used in low JNR situation to ensure a lower probability of false alarm.The MEP jamming detection algorithm is used in high JNR situation to make the probability of false alarm and leakage detection are decreased with the increase of JNR.And then performance of adaptive jamming detection is verified by simulation,the algorithm can meet the requirement of jamming detection in different JNR situation.The third part studies the jamming suppression algorithm of S-CFFH system.Firstly,the jamming suppression scheme for S-CFFH system is given,and the jamming suppression factor based on the Minimum Mean Square Error(MMSE)criterion is deduced.Then,this paper studies the maximum Ration Combine(MRC)and the maximum(ML),the two anti-jamming combining algorithms.And anti-jamming performance of the jamming suppression algorithm in S-CFFH system is simulated and analyzed.The simulation results show that jamming suppression performance based on MMSE criterion is better than that of traditional zero setting algorithm and amplitude limiting algorithm,ML combining algorithm performance and improving MRC combining algorithm performance are better than that of traditional MRC combining,and can effectively suppress pulsed jamming,partial band noise jamming and multi-tone jamming.The fourth part studies the multi-tone jamming cancellation algorithm,and proposes jamming cancellation algorithm based on single-tone/multi-tone jamming parameter estimation.Firstly,this paper proposes single-tone jamming parameter estimation algotithm based on iterative phase difference and iterative DFT,and multi-tone jamming parameter estimation algorithm based on interpolation DFT using three point.The parameter includes amplitude,frequency and phase of multi-tone jamming.And then the multi-tone jamming is reconstructed and eliminated.Next,this paper simulates the performance of the multi-tone jamming cancellation algorithm and the multi-tone jamming suppression algorithm in the S-CFFH system.The simulation results show that the multi-tone jamming cancellation algorithm can completely eliminate the influence of multi-tone jamming on the performance of S-CFFH system,and the performance is superior to the multi-tone jamming suppression algorithm.The fifth part mainly studies the anti-jamming algorithm of S-CFFH/SM system.Firstly,the error rate of Space Shift Key(SSK)is deduced,and the joint bit error rate of spatial modulation is simulated.The optimal allocation scheme of antenna bit and data bit is given.Then,this paper simulates and analyzes the anti-jamming performance of S-CFFH/SM system in the pulsed jamming,part of the band noise jamming and multi-tone jamming.The simulation results show that the anti-jamming algorithm is still applicable to S-CFFH/SM system,and has strong anti-jamming ability.