Subspace based direction of arrival estimation of DS-CDMA signals using orthogonal projection

In this paper a new method for direction of arrival estimation of direct sequence code division multiple access (DS-CDMA) signals in multipath fading environments is proposed. The method is based on suppressing the effect of coherent signals from different paths by orthogonal projection of the antenna's spatial-temporal output vector onto the undesired subspace. The method assumes the knowledge of the spreading code sequence and delays of the paths of the desired user and then applies the MUSIC algorithm with new transformed vectors. This method is applicable to all array geometries and does not need any spatial smoothing that is usually applied for coherent signals. The estimates of the proposed method are consistent and its performance is investigated through simulations.