Research On Reconnaissance And Interference Technology Of Underwater Acoustic Communication OFDM Signal

As one of the important research fields of marine resources development and national defense security construction,hydroacoustic communication has reached a high level.In the past,high communication rate,transmission distance and high reliability are the requirements of hydroacoustic communication,but with the continuous improvement of national defense demand and the continuous progress of cooperative communication technology,non-cooperative communication has become one of the important research fields in the development of hydroacoustic communication in recent years.In the field of non-cooperative communication,reconnaissance and interference technology is very important in both military and civilian departments,reconnaissance can intercept information signal detection,spectrum supervision,interference can help to choose the best anti-jamming mode transmission,to ensure the smooth progress of communication,so reconnaissance and interference is particularly important for communication systems.Reconnaissance in non-cooperative communication systems mainly includes signal recognition,parameter estimation and subcarrier modulation,and studying interference will effectively guarantee the communication performance of the signal.On the basis of non-cooperation,the detection and interference technology of OFDM signal is studied on the basis of OFDM signal.The main research work is as follows:1.Analysis of the principle of OFDM signal,research the characteristics of OFDM signal.Three single-carrier signals are compared with OFDM signals,and the OFDM recognition algorithm based on high-order accumulation and wave-wave transformation methods is studied from the perspective of signal processing.Based on the sample of OFDM signal,the feasibility of the recognition algorithm is simulated and the performance of the algorithm is verified by lake tests.2.The method of estimating the parameters of OFDM is studied.The effective symbol length estimation algorithm based on intrinsic correlation,the bandwidth estimation algorithm based on 3d B,and the algorithm based on the maximum liked method and the cycle prefix length estimation algorithm based on fixed movement are studied.Based on the sample of OFDM signal,the feasibility of parameter estimation algorithm is simulated and the performance of the algorithm is verified.3.The study of OFDM signal sub-carrier modulation method recognition method.Two methods are used to identify the subcarrier modulation,one is based on mixed high-order moments and the other is based on the nearest neighbor method.Finally,based on OFDM sample data,the validity of the two recognition algorithms is verified and analyzed,and the performance of the algorithm is verified by lake tests.4.To study the anti-jamming of OFDM signals.The anti-jamming performance of signal under broadband noise interference,partial band interference,pulse interference and tone interference is analyzed.The performance of this method is verified by simulation.In summary,the paper studies the identification of OFDM signal,parameter estimation,subcarrier modulation method and interference technology of OFDM signal,and verifies the feasibility and validity of the corresponding algorithm through simulation and lake test.