中文摘要：

结合我校研究生所开设的现代通信系统课程,设计了隧道内无线通信系统实验的一个拓展内容——隧道内小时延多径信号分集接收方法探索及其仿真实验。由于纳秒级多径信号密集,致使隧道内无线通信质量急剧下降,通信距离严重受限。为了达到隧道内可靠通信距离增加的目的,本实验针对隧道内复杂环境,如背景噪声大、纳秒级多径密集的特点,提出了CFOC-MN纳秒级时延估计算法,并用其改进传统瑞克分集接收机,使其能够变密集的、且时延扩展为纳秒级的隧道内多径为有利信号。实验结果表明：提出的CFOC-MN纳秒级时延估计算法改进瑞克分集接收机,有效提高了接收信号的信噪比,能够达到延长可靠通信距离的效果。

英文摘要：

Combined with school ＇s graduate course of modern communications systems,an expanding content of reception technology of small delay multipath signal is designed. In underground tunnel environment,small delay multipath signals are dense,therefore multi-path fading in a mine tunnel is more severe than that in open environment.It leads to sharp declines in quality of wireless communication and a unwanted limited in communication distance. In order to inhibit multi-path fading in tunnels,the diversity reception technology of small delay multi-path signal was discussed. This paper proposed the CFOC-MN delay estimation algorithm for heavy background noise to improve the traditional RAKE receiver,which transformed the dense multi-path signal. The delay spread was at ns level. Simulation results show that the performance of RAKE diversity receiver can effectively improve the SNR of received signal,and can achieve the effect of extending the reliable communication distance.