A New Subspace Method for Direction of Arrival Estimation of Multipath Signals in DS- CDMA Systems

In this paper a new sub-space method for estimating the direction of arrival (DOA) of coherent signals at the base station of a direct-sequence code division multiple access (DS-CDMA) communication system is proposed. In this method, the signal subspace of the desired user is decomposed into proper smaller sub-spaces to resolve the spatial temporal signatures of the coherent received signals. The idea is based on exploiting the spreading code sequence of the user to derive a set of vectors constructing a subspace where a part of the desired spatial temporal signature lies. Using a step by step procedure, all DOAs of different paths of the desired user are obtained by the well-known MUSIC algorithm.