基于上行信道盲估计的宽带码分多址用户检测器

针对宽带码分多址（CDMA）系统中同时存在多址干扰与码间串扰的情况进行研究,给出了适用于宽带CDMA系统的卷积模型,利用子空间技术及已知的扩频码信息,将适用于单用户的单输入多输出系统信道盲估计方法扩展到码发侈址系统中,实现了多用户上行信道的盲估计,利用有限码集特性,解决了上行信道盲估计中存在不确定复系数的问题,在此基础上,给出了最小均方误差多用户检测器的实现方案,计算机仿真实验证明,提出的方法可以同时克服多址干扰及码间串扰,是实现宽码分多址系统多用户检测的一个有效途径,同时该方法还可以推广到基站采用智能天线的系统中,实现对矢量信道冲激响应有的盲估计。

Multiuser Detection for Wideband Code Division Multiple Access Systems Based on Blind Uplink Channel Estimation

The wideband code division multiple access (CDMA) systems with both multiple access interference (MAI) and inter symbol interference (ISI) are investigated.The convolution model suitable for wideband CDMA is proposed.Utilizing the subspace technology and the known spreading code information,the blind channel estimation method for single user in the case of single input and multiple output is expanded to the CDMA,and the uplink channels of the multiple users can be estimated simultaneously.The ambiguous coefficients caused by the blind channel estimation are identified by the finite alphabet property of the digital communication systems.Based on the estimated channel,a linear minimum mean square error multiuser detector has been constructed.The computer simulation demonstrates that the new method can overcome the MAI and ISI,and it is valid for the realization of multiuser detection of wideband CDMA.The new method can also be expanded to the base station with antenna array and can realize the estimation of vector channel impulse response.