Research And Simulation On Self-encoded Frequency-hopping Communication System

The concept of a novel secure communication technology named self-encoded spread spectrum (SESS) communication was first proposed by Lim professor who was from American in1999.It uses transmission source data generated spread code,instead of using pseudo-random code generator to ensure the random spreading sequences, random and dynamic variabilityStephen F.Fahey and Lim Nguyen first introduced the concept of self-encoded into the frequency hopping(FH) system in the2010conference papers. This paper describes the principle of self-encoded frequency hopping systems and analysis of the stability of the system.The study of SESS is based on direct sequence spread spectrum (DS-SESS) system at home and abroad before this paper.But the DS-SESS system is limited by the need for the continuous spread spectrum bandwidth impact, limiting the system processing gain.FH eliminates this limitation, it has good bandwidth efficiency and better resistance to intended jammer.Firstly,the basic principles of self-encoded frequency hopped(FH-SESS) system is introduced in detail in thid paper.On this basis, the FH-SESS system simulation model in additive white gaussian noise channel(AWGN) is built by MATLB. Then the performance of parameters on system and the easibility, together with problems of the FH-SESS are analyzed by compared with traditional frequency hopping system error rate.After a survey of the system performance some improved approaches are discussed. Sencondly, the principle of multi-user of SESS system is introduced.Then the system bit error rate and the performance of iterative interference cancellation algorithm is simulated and analyzed.The FH-SESS system performance in low sigal-to-noise ratio is poor by compared with the traditional using pseudo noise code(PN) frequency hopping system because of self-interference lead to the spread of bit error.In order to improve the performance of SESS systems, several programs are described:turbo codes are introduced in FH-SESS system, combined with FH-SESS system combined with the error correction code model is simulated and analyzed; adaptive filter autoregressive (AR) model and the inverse process (whitening filter) to achieve SESS system source sequence randomization is introduced;Finally,the method using a chaotic sequence to get out of SESS hopping sequence is proposed and then the performance of the method is simulated and analyzed.