序列扩频UWB通信系统的Rake接收性能分析

Performance evaluation of Rake receiver for spread spectrum UWB systems

基于一个能较好描述超宽带(UWB)信号传播特性的S-V室内多径传播统计信道模型,对高速序列扩频的UWB系统Rake接收机设计中的若干关键问题进行了详细仿真和分析。结果表明,在该信道下,选择合并Rake(S-Rake)接收机或有限合并Rake(L-Rake)接收机的性能显著优于部分合并Rake(P-Rake)接收机。通过5～10个Rake接收支路的等增益合并(EGC)能够较好地克服符号间干扰(ISI)和码间干扰(ICI),而不需要使用复杂的均衡器。

The performance of Rake receivers in spread spectrum UWB (ultra wideband) systems with high pulse repetition frequency was studied using a realistic UWB indoor channel. General Rake reception models were developed for direct sequence spread spectrum (DSSS) and M-ary bi-orthogonal keying (MBOK) spread spectrum UWB systems. The simulation results illustrate the tradeoff between performance and receiver complexity. The results show that, in this UWB channel model, the equal energy capture (EGC) Selective Rake (S-Rake) receiver and the Limited Rake (L-Rake) receiver are more applicable than the Partial Rake (P-Rake) receiver. More importantly, spread-spectrum UWB systems may use 510 Rake taps for energy capture, while relaxing the equalizer requirement to combat inter-symbol-interference.