Channel estimation for synchronous DS-CDMA downlink

Synchronous code-division multiple-access (CDMA) techniques possess intrinsic protection against co-channel interference due to the orthogonal spreading codes used. However in the presence of multipath the signals lose their orthogonality property leading to increased cross-correlation. In these cases channel estimation may be needed in order to improve the detection of the desired symbols. We propose a subspace-based algorithm for blind channel estimation of a synchronous CDMA downlink. We compare the channel estimation accuracy with the Cramer Rao bound and we show that the estimation accuracy can be increased considerably using a decision feedback approach.