基于Chebyshev混沌扩谱序列的MC-CDMA系统的峰均功率比研究

峰均功率比(PAPR)是多载波码分多址 (MC-CDMA)系统的一个重要指标, OFDM多载波调制技术虽然可以提高MC-CDMA系统的数据传输率和抗干扰能力, 但是在系统的峰均功率比方面则存在着亟待解决的问题。本文利用Chebyshev混沌扩谱序列的伪随机、非周期、数量大和良好的相关特性,作为MC-CDMA系统上行信道的扩谱序列,以改善输出信号的峰均功率比。分析和仿真结果表明在保持较低多址接入干扰的同时,还可以大大降低发射信号的峰均功率比。

The Peak-to-Average Power Ratio of MC-CDMA with Chaotic Chebyshev Spread Sequence

Although the OFDM multi-carrier technique offers high data rate and immunity to multipath fading, the high peak-to-average power ratio(PAPR) of OFDM signal severely limits its applications. This undesirable property remains in MC-CDMA scheme which is an extension of the basic operation of OFDM-CDMA. Taking the advantage of random-like, non-periodic and excellent correlation property of chaotic sequence, the authors recommend using them as the spread sequence of MC-CDMA in the uplink channel in order to lower the PAPR of OFDM multi-carrier modulation. The analysis and simulation results prove that this scheme not only shows the better performance of PAPR but also realizes the Selective Mapping (SLM )based on chaotic sequences to further cut down the PAPR.