A novel subspace based method for direction of arrival estimation of signals in a multi-path CDMA system

This paper presents a method for finding the directions of arrival of coherent signals in a multi-path asynchronous DS-CDMA system. The method is a time-space processing method and works with the temporal-spatial signatures of the signals. It is a blind method which exclusively uses the desired user's spreading code sequence and the path delays of the desired user to eliminate the contribution of undesired paths. The basic idea is to exploit the desired user's temporal characteristics to apply a linearly transformation to the existing signal subspace to find a new subspace onto which the desired path's signal's temporal-spatial signature lies. Once it is accomplished, the well-known MUSIC algorithm can be applied to find the desired direction of arrival. For evaluation purposes, some simulation results are presented.