基于张量分解和多项式库搜索的多天线NPLC-DS-CDMA伪码序列估计

针对低信噪比下非周期长码直接序列码分多址(NPLC-DS-CDMA)信号伪码序列估计问题，该文提出一种基于张量分解和多项式库搜索的多天线估计方法。该方法首先对接收信号建模为3阶张量模型并根据扩频增益分割为多个子张量，然后利用交替最小二乘投影(ALSP)算法对子张量进行CP分解得到伪码片段因子矩阵和接收增益因子矩阵，利用接收增益矩阵互相关性和旁瓣能量检测对伪码片段组合序列筛选得到每个用户的伪码序列，最后利用多项式库搜索的方法识别出伪码序列的生成多项式，进一步提高伪码序列估计的正确率。仿真结果表明，所提方法能够实现对NPLC-DS-CDMA信号伪码序列的有效估计。

Estimation of the Pseudo Noise Sequence for Multi-Antenna NPLC-DS-CDMA Signals Based on Tensor Decomposition and Polynomial Library Search

To deal with the problem of estimation of the pseudo noise sequence for Non-Periodic Long Code Direct Sequence Code Division Multiple Access (NPLC-DS-CDMA) signals under low signal-to-noise ratio, a method using multi-antenna based on tensor decomposition and polynomial library search is proposed. Firstly, the received signals are modeled as a third-order tensor model and the tensor is divided into multiple sub-tensors according to the spreading gain. Secondly, the pseudo noise code fragment factor matrixs and the receiver gain factor matrixs are obtained from the sub-tensors by Canonical Polyadic (CP) decomposition which uses the Alternating Least Squares Projection (ALSP) algorithm, and then the pseudo noise sequence of each user is obtained by selecting pseudo noise code fragment combination sequence according to the cross-correlation of the receiver gain factor matrixs and sidelobe energy detection. Finally, the polynomial library search method is applied to identifying the generator polynomial of the pseudo noise sequence in order to further improve the accuracy of the pseudo code sequence estimation. The simulation results show that the proposed method can effectively estimate the pseudo noise sequence of the multi-antenna NPLC-DS-CDMA signals.