移动通信中的信道参数估计Cramér-Rao下界研究  

Cramér-Rao lower bound of the channel parameter estimation in mobile communications

作　　者：李溯南 华惊宇[1] 姜胜园 周凯[1] 徐志江 Sunan LI Jingyu HUA Shengyuan JIANG Kai ZHOU Zhijiang XU(College of Information Engineering, Zhejiang University of Technology, Hangzhou 310023, China Zhejiang Provincial Key Laboratory of Communication Networks and Applications, Hangzhou 310023, China)

机构地区：[1]浙江工业大学信息工程学院,杭州310023 [2]浙江省通信网技术应用研究重点实验室,杭州310023

出　　处：《中国科学：信息科学》2017年第7期904-914,共11页Scientia Sinica(Informationis)

基　　金：国家自然科学基金(批准号:61471322)资助项目

摘　　要：在移动通信中,信道增益噪声方差和Doppler频移等参数的估计具有重要意义.然而移动台的相对运动使得传输信道变成时变信道,这降低了参数估计的准确性.因此本文研究一般时间选择性信道的参数估计方差界推导,即有限样本Cramér-Rao下界(CRLB),推导时考虑Doppler扩展、方向性散射以及加性噪声的联合影响.这些界对于评估相应信道参数估计器的性能极为有益.为了处理信道功率谱密度(power spectrum density,PSD)边界的奇异性,本文提出了一种近似谱密度方案,解决了非近似方案无法适应PSD边界不可微的缺陷.数值计算结果表明,只要样本数满足一定的条件,近似方案可以获得与非近似方案逼近的CRLB计算结果,但是前者扩展了计算方法对于Doppler频移范围的适应性.Estimations of channel gain, noise variance, and Doppler shift are of great importance in mobile communications. However, the relative motion of the mobile transceiver results in time-varying channels and,therefore, degrades the accuracy of channel parameter estimators. Thus, this paper attempts to characterize such degradations in a general time-selective channel environment, where we derive finite-sample Cram′er-Rao lower bounds（CRLB） by assessing the joint effects of Doppler shift（mobile speed）, direction of propagation, and additive white noise. These bounds will provide insights into the potential for the estimation of the aforementioned channel parameters. Furthermore, an approximation scheme is proposed in order to tackle the boundary singularity of the channel power spectrum density（PSD）. Numerical computations demonstrate that the approximated method produces similar results to the non-approximated method, so long as the sample number satisfies a certain condition. Additionally, the approximated method effectively extends the applicable Doppler range of the non-approximated method.

关 键 词：Cramér-Rao下界 时变信道 参数估计 功率谱密度 移动通信 

分 类 号：TN929.5[电子电信—通信与信息系统]