基于优化混沌扩频序列的DS/CDMA系统

Improved DS/CDMA System Performance Based on Optimal Chaotic Sequences

混沌序列以其相关性好、对初值敏感、保密性强等特性成为直序码分多址(DS/CDMA)系统中性能较好的一种扩频码.为了提高DS/CDMA系统保密性,降低多址干扰,提出了一种优化作为扩频码的混沌序列性能的算法,并将该算法运用于常用的3种混沌序列,比较了优化后的混沌序列应用于DS/CDMA系统中的性能.结果表明,优化后的改进型Chebyshev序列能提供较大的系统容量,抗多址干扰能力强,且系统误码率较低.

Chaotic sequence, with its good correlation performance, being sensitive to initial condition and hard to be decrypted, has been used as spread spectrum code in DS/CDMA system. In order to improve the security of the DS/CDMA system and decrease the muhiple access interference, an optimization algorithm for choosing chaotic sequence as spread spectrum code was proposed. Three common chaotic sequences were optimized with the algorithm and the performance of the DS/CDMA systems adopting these three chaotic sequences was compared. The results showed that the optimal improvable Chebyshev-map had larger capacity, lower multiple access interference and bit error rate than others.