Research On Multi-carrier Signal Detection Method

Signal detection and recognition in non-cooperative communication is very meaningful.Especially in terms of radio spectrum management and military information acquisition.Orthogonal Frequency Division Multiplexing(Orthogonal Frequency Division Multiplexing,OFDM)technology is widely used as a multi-carrier signal.Detecting OFDM signal is of great significance in non-cooperative communication.In this paper,non-cooperative OFDM signal detection is the focus.By studying the characteristics of OFDM signals,the purpose is to improve the detection performance of multi-carrier signals under low SNR.The main research contents are as follows:1.The multi-carrier signal detection algorithm based on statistical characteristics is studied.The high-order cumulants detection method for non-cooperative communication is studied.According to the statistical characteristics of OFDM signals,it is found that OFDM signal has asymptotic Gaussian property,but single carrier signal do not have this feature.Based on this characteristic,the detection algorithm of Gaussian channel and Rayleigh channel is studied.It includes detection algorithm based on higher order cumulants,detection algorithm based on higher order mixed moment,and joint algorithm based on higher order cumulants and higher order moment.The characteristic parameters are constructed by using the sixth order cumulants,fourth order cumulants sand second order cumulants of the signal.According to the characteristics of the constructed characteristic parameters,a new threshold method for multi-carrier signal detection is proposed.This method effectively improves the reliability and accuracy of the detection algorithm.2.The detection algorithm based on cyclic prefix is studied.In order to further improve the multi-carrier signal detection scheme,the algorithm based on statistical characteristics cannot distinguish Gaussian signal from OFDM signal.Using the OFDM signal after adding the circular prefix,The stationary characteristics and correlation of multi-carrier signals present an algorithm for distinguishing Gaussian signals from OFDM signals.The cyclostationary characteristics of OFDM signals and the antijamming performance of second-order cyclic cumulant are analyzed.The detection algorithm based on cyclostationary characteristics and the detection algorithm based on cyclic prefix are studied.And analyzed the advantages and disadvantages of the two algorithms in anti-jamming performance and algorithm complexity.3.Aiming at the problem of multi-carrier signal detection under non-traditional noise,the detection algorithm based on generalized cumulant under Alpha stable distribution noise is studied.The properties and characteristics of Alpha stable component noise are studied by taking Alpha stable distribution noise as signal noise.Analyzed the influence of this noise on traditional signal detection algorithms.Nonlinear transformation method and generalized cumulant are defined to solve the problem of traditional detection algorithm failure.A multi-carrier signal detection algorithm based on generalized cumulant is presented.Combined with the relevant knowledge of the higher-order cumulants in Chapter 3,new characteristic parameters are proposed.Compare the performance of two detection algorithms based on generalized cumulant.According to the simulation results,the detection accuracy of the newly proposed feature parameters under low SNR is higher than that of the old scheme.Finally,the simulation and analysis of the influence of the feature index on the performance of the detection algorithm are given.And provide a new idea for follow-up research.