Estimation of covariance matrix of downlink channel in FDD-CDMA systems
Guannan Zhao · Radio and communications technology · 2006
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.