Generation And Characteristics Of Self-encoded Spreading Sequence

Pseudo-Noise (PN) codes have been widely used as spreading codes indirect sequence spread spectrum (DSSS) system. However, with thedevelopment of electronic counterwork, the transmission security of PN codeswith fixed spectrum has been threatened.At 1999, Lim Nguyen first brought forward a novel self-encoded spreadspectrum(SESS) system whose spread spectrum sequences are full built by thesource data instead of using PN codes. Appropriate methods are needed toassure random nature of spreading codes got from source data. Usually weemploy data compression methods to remove any redundancy in the datastream. However, the variability of spreading codes changes with differenttransmission data. The performance of the system is instability. To solve thisproblem, we need a dynamical method to generate spreading codes. In thispaper, we present a novel method which employs auto regressive (AR) filtertheory. It can be adaptive with the change of source data stream.On the basis of principles of DSSS and SESS, the mechanism of SESSemploying the AR filter is illuminated. The models of SESS and self-encodedmultiple access(SEMA) are built and simulated in the AWGN channel and inRaleigh fading channel. The simulation results show the SESS with AR filtercan be just as reliable as the conventional DSSS. The approach can also adjustthe self-interference(SI) owned only by SESS.The qualities relative to the spreading codes generated by AR filter arestudied in this paper. Such as correlative character, codes balance, linearcomplexity and the BER performance in the AWGN channel. This paper alsoincludes the introduction of the application of SESS in multiple access system,in time-hopping and frequency-hopping communication system.At last, the thesis summarizes the work and point out some study directions.