A Maximum Likelihood Estimation of Subchip Multipath Parameters

To solve the estimation problem of multipath channel parameters in CDMA mobile satellite communications, a two-dimensional searching algorithm based on maximum likelihood estimation is proposed. The proposed algorithm searches for delays of two paths. Meanwhile, the magnitude of multipath is estimated using de-correlation or Linear Minimum Mean Square Error (LMMSE) algorithm. The optimal delay and amplitude estimation is finally found by maximizing the likelihood function. Simulation results show that the proposed algorithm, which combines a two-dimensional searching with approximate LMMSE estimation of multipath magnitude, performs well.