瑞利衰落信道下扩频通信系统抗多径干扰性能研究

在一种新的实用瑞利衰落信道下,存在加性高斯白噪声,对直接序列扩频(DSSS)通信系统抑制码片内、外多径干扰的能力进行理论分析与计算机仿真。证实扩频通信系统在多径瑞利衰落信道中传输时能有效地克服多径衰落;在多径衰落信道较强的条件下,与提高扩频增益相比,增加扩频码的码长对于提高移动通信系统的抗多径衰落性能更加有效,但是扩频增益并非越高越好,需合理选取。

Anti-Multipath Capability in Spread Spectrum Communication System over Rayleigh Fading Channels

Firstly, the effects of multipath fading with time delay shorter or longer than one chip interval on direct sequence spread spectrum (DSSS) are mathematically and experimentally researched in multipath Rayleigh Fading channels.Secondly, under the software environment of MATLAB/Simulink, the relationship curves of the bit error rate (BER) and the signal-to-noise ratio (SNR) of DSSS communication systems are presented.Simulation results indicate that DSSS system can efficiently overcome multipath fading in multipath Rayleigh Fading channels.The spreading gain is not the higher the better, so that it must be chosen reasonably.In addition, compared with improving the spreading gain, increasing the PN code length is more effective on improving the anti multipath fading performance of the whole communication system.