时变瑞利信道下异步长码MC-CDMA系统性能分析

Performance Analysis of Multicarrier CDMA Systems in Rayleigh Channel

考虑异步时延、随机扩频序列、多普勒频移和多径对异步长码MC-CDMA上行链路系统性能的影响,选择合并信号的信号干扰噪声功率比(SINR)最大原则进行分集接收,假定各条路径的衰落均满足瑞利分布,给出了此最优分集合并滤波器在时变瑞利信道下MC-CDMA系统的平均SINR的解析形式,并进一步分析得到了系统的误比特率(BER)性能.计算机仿真验证了本文理论的正确性.

Rapid time variation of the mobile communication channel have a dramatic effect on the performance of multicarrier modulation. The performance of the uplink of asynchronous multicarrier code-di- vision multiple-access （MC-CDMA） systems with aperiodic random spreading and Raleigh fading is studied in this paper. We obtain the optimum combining filter that maximizes the signal-to-interference-plus-noise （SINR） of the combined statistics and exploits correlated information among subchannels. A closed-form expression for the unconditional covariance matrix of the interference-plus-noise vector and bit error rate （BER） in Rayleigh channel are derived. The performance of the MC-CDMA systems is evaluated by numerical simulation.