一种DS-CDMA扩频序列的盲估计方法  

Approach to blindly estimate spreading sequence of DS-CDMA

作　　者：苗圃[1] 张天骐[1] 黄铫[1] 刘燕丽[1] 

机构地区：[1]重庆邮电大学信号与信息处理重庆市重点实验室,重庆400065

出　　处：《计算机应用研究》2010年第2期649-652,656,共5页Application Research of Computers

基　　金：国家自然科学基金-中物院NSAF联合基金资助项目(10776040);国家自然科学基金资助项目(60602057);重庆市科委自然科学基金资助项目(CSTC;2009BB2287);重庆市科委信号与信息处理重庆市市级重点实验室建设项目(CSTC;2009CA2003)

摘　　要：针对低信噪比条件下直接序列扩频码分多址(DS-CDMA)信号扩频序列盲估计的难题,提出了一个能对同步和异步的短码调制DS-CDMA信号的扩频序列进行盲估计的新方法。该方法在分析接收信号特征结构及其相关矩阵结构的基础上,首先估计出接收信号中一个用户信号的功率、特征扩频序列的失步点及序列本身,再用已经估计出来的特征信息对相关矩阵进行缩减,以消除该用户对剩余用户信号估计的影响。依此方法,逐次迭代,最后完成对接收信号中所有用户信息的盲估计。所估计出用户信息的顺序与其功率大小密切相关,功率越大的用户,就越先被估计出来。理论分析和计算机仿真表明,该方法能够在低信噪比条件下较好地完成DS-CDMA扩频序列的盲估计。According to the problem that the blind estimation of direct spread division multiple access （DS-CDMA） signals＇ spreading code was difficult to be obtained in low SNR, this paper proposed a new approach to blindly estimate the spreading code of short code DS-CDMA in synchronous and asynchronous conditions respectively. The approach bases the analysis to the received signals＇ feature structure and its correlation matrix＇ s structure, then used the obtained estimations to deflate the correlation matfx, so could clear its influence to the estimation of the residual signals. Based on the approach, reduced the dimension of the signal subspace at each iteration so that the spreading code and desynchronizing point of the next user could be estimated reliably. At last, completed all the users＇ blind estimation. The order of a user signal being estimated is closely related to its power, i.e. the user which has the bigger power is earlier and easier to be estimated. Theoretical analysis and simulation results show that the proposed approach can effectively estimate the spreading code of DS-CDMA.

关 键 词：失步点 扩频码 同步 异步 盲估计 

分 类 号：TN911.7[电子电信—通信与信息系统]