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.