Abstract: The Time-Hopping Pulse Position Modulation (TH-PPM) is one of the most popular approaches for IR-UWB multi-user systems, and a lot of research efforts have been devoted on its performance analysis. In several latest literature, a method of numerical computation of MAI characteristic function was carried out to derive precision analytical error performance, which, however, still showed a few inconvenient limitation on the system configuration. To overcome this shortage, the corresponding MAI model is enhanced in this paper, and the multi-access BER performance expression is also derived based on this modified model. Finally, Monte-Carlo simulations are carried out to verify the analytical results.

Key words: ultra-wideband, time-hopping pulse position modulation, multiple-access interference, bit error rate

摘要： 跳时-脉冲位置调制方式（TH-PPM: Time-Hopping Pulse Position Modulation）是IR-UWB系统中最常用的多址调制方式之一，针对该多址方式的性能分析一直是UWB技术研究的一个热点。一些文献采用多址干扰特征函数直接数值计算的方法对相干接收方式下异步UWB多用户系统的误码性能进行了分析并获得了精确的数值分析结果，但是相应的分析过程中存在着一定的系统参数设置约束。针对现有多用户干扰模型的不足进行了改进和完善，并推导了相应的MAI概率分布和多址干扰误码性能解析表达式。最后通过Monte-Carlo计算机仿真，对改进模型下理论分析结果的有效性进行了验证。

关键词: 超宽带, 跳时-脉冲位置调制, 多址干扰, 误码性能