FDD-CDMA系统下行信道协方差矩阵的估计

Estimation of covariance matrix of downlink channel in FDD-CDMA systems

针对在基站采用天线阵列的FDD-CDMA系统下,讨论利用上行链路的接收数据,通过码滤波后的数据协方差矩阵得到某一条路径的等效方向向量。在不求出DOA的情况下,采用离散傅里叶变换来估计该路径下行信道协方差矩阵。计算机仿真表明:在FDD-CDMA系统中,尽管上下行载波频率相差很大,采用上述方法仍能将波束的主瓣对准期望用户,并且与传统的DOA方法相比较,降低了由于解非线性优化所带来的计算复杂度。

For FDD-CDMA systems using antenna array in base station, the paper, which discussed using received data of uplink, obtained an equivalent direction vector of one path by data covariance matrix after code filtering. DFT is used to estimate the covariance matrix of downlink channel of the path, not calculating DOA. The results of computer simulation indicates that the method makes mainlobe of antenna collimate expected user in FDD-CDMA systems though difference between downlink and uplink carrier frequency is big. To compare with classical DOA, the approach decrease the computation complexity arouse from solving nonlinearity optimization.