Performance Enhancement of DS/SS System Using Hybrid Chaotic Spreading Sequence

In this paper, a chaotic sequence generator based on logistic map and an interleaver is proposed and used to generate spreading sequence. The generated chaotic sequence is balanced itself and has excellent correlation property and sidelobe property. When the sequence is applied to direct sequence/spread spectrum (DS/SS) system, multiple access interference (MAI) can be mitigated by using the spreading sequences. The system capability, performance can be enhanced, and the information can be effectively encrypted. The bit-error rate (BER) performance of spreading sequence from the proposed chaotic sequence generator is compared with that of the conventional m-sequence and Gold sequence. Results show that the new sequence has a noticeable improvement in BER performance in low signal-to-noise ratio (SNR). Although the chaotic sequence has more excellent correlation property and sidelobe property, it is easy to be implemented.