Multipath direction finding with frequency allocation subspace smoothing for an OFDM wireless communication system

In smart antenna systems, the DOA (direction of arrival) based beamforming algorithms use the information of users DOAs to detect the desired user´s signals and suppress other interference. However, in the real wireless environment, the subspace based high resolution DOA estimation algorithms will fail to estimate the correct DOA because of the loss of rank caused by the correlation between the received signals. This paper proposes a new smoothing algorithm associated with OFDM technique to solve the problem of loss of rank. In the simulation, the proposed algorithm with TLS ESPRIT is used to estimate the DOAs. The simulation results showed that this algorithm can really solve the problem of loss of rank in the multipath channel and accurately estimate DOAs of the signals