Research Of SESS/FH Hybrid Spread-Spectrum Base On Chaos Sequence

Spread-spectrum technique has been widely used in military and civilian communications for its unique advantages such as anti-jamming,low probability of detection(LPD) and Low Probability Intercept, multiaddress acess ,But modern electronic counterwork technic could exactly estimate the carrier frequency,signal period,even the pseudo-random sequence itself of DSSS;FH signal blind parameter estimation based on array signal processing has become the focus of the research.So it's necessary to find the new code.A SESS/FH hybrid spread spectrum based on chaos sequences is proposed in this paper. SESS refers to Self-Encoded Spread Spectrum system,which dosen't use PN codes,whose spread specturm sequence are full built by the sourse data. Due to the variability of spreading codes changes with different transmission data, the performance of the system is instability. To solve this problem ,we present a novel method which employs auto regressive(AR) filter theory which widely used in modern spectral estimation to generate spreading codes.At the sametime,we introduce chaos sequence instead of traditonal PN codes as FH pattern. So we discuss the usage of Chaos sequence at chapter 3. First, we introduce the principle and building method of chaos sequence and some famous chaos sequence. Then, we discuss the usage of Chaos sequence in SESS and FH.At last,we design a DDS based on chaos sequence.Synchronization acts an important role in spread sprctrum communication.lts include two processes:acquisition and tracking. In hybrid Spread Spectrum system, we separtately proposed a new synchronize method in DS and new method in FH.And at last ,in chapter 4,we analysed and simulated theose methods. Its performance is no less than traditional PN sequence.