A spatial approach to source localization in CDMA systems

We adopt a spatial approach for the localization of the radio network users. For this, the problem of direction of arrival (DOA) estimation and association of signals impinging on a passive antenna is addressed. A subspace-based method is proposed to estimate and associate the DOA of radio cochannel users multipaths. The proposed algorithm allows a separate localization of the users by using pilot symbols. It handles the inter symbol interference (ISI) introduced by the transmitter pulse shaping filter and the temporal spread introduced by frequency selective channels. The algorithm is then applied to CDMA signals for which the separate localization of the users is achieved blindly, using only their spreading codes (no pilot symbols).