Cramer-Rao界及其在DS-UWB同步问题中的应用

在充分考虑了IEEE定义的UWB多径信道模型以及由此产生的多径干扰的基础上，推导出一种适用于DS-UWB通信系统中数据有助（DA）和数据无助（NDA）方式下同步捕获的理论界限--修正的Cramer-Rao界。通过与基于滑动相关捕获算法的DS-UWB捕获性能的比较，证明了该理论推导结果的有效性，并得出了系统的捕获性能会随着多径时延的增加而急剧下降的结论。

Cramer-Rao bounds and its Application in Synchronization of DS-UWB

Synchronization process is much complicated and essential in Ultra-Wide band (UWB) communication system for its special characteristics, extremely short transmitted pulse shape and ultra dense multi-path interference. A close-form expression of Modified Cramer-Rao bounds (MCRBs) for DS-UWB both in data-aided (DA) and non-data aided (NDA) acquisition scheme is derived. IEEE defined standard channel models are adopted in the presents of multi-access interference (MAI) during derivation. The validity of this derivation result is also confirmed by comparing this derived limit of theoretical performance and classical sliding correlation acquisition algorithm with computer simulation in fixed observation window. Meanwhile, a conclusion is obtained that the derivation under prior assumptions is a feasible tight lower bounds and the increase of multi-path delay in environment weakens the estimation performance of timing delay.