中文摘要：

该文提出了一种基于可变长训练序列的自适应直扩超宽带（DS-UWB）接收机。该接收机充分利用自适应NLMS算法在收敛性、复杂度及稳定性方面的综合优势，以较小的训练开销实现了自适应接收机的功能。理论分析及计算机仿真实验表明，在误码性能相当的前提下，所提出的自适应接收机比传统的Rake接收机具有更为简单的结构，同时与现有的自适应接收机相比，其训练序列的开销可节省60％以上，因而适用于低功率、低成本以及简易实用的室内超宽带应用场合。

英文摘要：

An adaptive receiver scheme employing the training sequences of flexible length is proposed for DS-UWB systems. By fully exploiting the NLMS algorithm＇s robust behavior on convergence rate, complexity and stability, the proposed scheme is capable of performing an adaptive receiver with its low cost in terms of training bits, Theoretical analysis and simulation results show that, without loss of the BER performance, the proposed scheme can achieve a simpler structure compared with the traditional coherent Rake receiver and a higher throughput compared with the conventional adaptive receiver scheme, and therefore can be considered as a promising candidate for low cost, low power consumption and low complexity indoor UWB application scenarios.