基于SMC的STBC-MC-CDMA信号扩频码及信息序列盲估计

Blind Estimation of Spreading Codes and Information Sequences for STBC-MC-CDMA Signals Based on SMC

针对具有空时分组码的多载波CDMA(Space Time Block Coding Multi Carrier Code Division Multiple Access,STBC-MC-CDMA)信号扩频码及信息序列的联合估计问题,结合序贯蒙特卡罗(Sequential Monte Carlo,SMC)算法和卡尔曼滤波技术,充分利用STBC和OFDM(Orthogonal Frequency Division Multiplexing)调制的正交属性,提出了一种快速的盲解扩算法.该算法通过将信号模型按不同符号路数和天线数目进行分段处理,采用卡尔曼滤波方法对均值和协方差进行迭代更新,并用一组带有权值的抽样粒子来近似建立的联合后验概率分布,根据抽样值和重要性权值大小进行参量状态估计,大大提高了算法的计算效率.理论分析和仿真结果验证了本文算法的有效性.

To deal with the problem of blind estimation of spreading codes and information sequences for space-time block coded multi-carrier CDMA signals, combined with SMC （ Sequential Monte Carlo） and Kalman filtering techniques, this paper introduces a fast blind despreading algorithm by making full use of the orthogonality property of the STBC and the OFDM multi-cartier modulation. Firstly, the proposed algorithm segments the signal model through different symbols and an- tennas. Secondly,use Kalman filtering method to update the mean and covariance iteratively. Then, use a set of properly weighted samples to approximate the joint posterior distribution, Finally, exploit these samples to estimate the quantity of in- terest, which improve the computational efficiency greatly. The theoretical analysis and simulation results verify the effective- ness of the proposed algorithm.