Joint parameter estimation of multiuser asynchronous DS CDMA signals in unknown fading channel in DS CDMA system with multiple antennas at the base-station and single antenna at the mobile

Abstract

We present MUSIC type algorithm for joint parameter estimation in asynchronous DS CDMA system with multiple antenna system at base station and single antenna system at the mobile users. The proposed algorithm is applied in downlink processing and it enables the joint estimation of time delay frequency shift as well as spatial parameters (direction of departure - DOD of transmitted signal) of asynchronous DS CDMA signals using single antenna system at the mobile. The proposed algorithm is well suited to unknown fading channel, frequency selective or dispersive, and it can be primarily used as a method of multipath channel identification. It seems to the authors that it can be used as a basis for the further improvement of process of detection at the mobile receiver. The proposed algorithm is near-far resistant, requires no preamble, and can be applied when the user sequences are not perfectly orthogonal.