Direction of arrival estimation of coherently distributed sources based on unitary ESPRIT in MIMO channel models

In MIMO channel, the presence of scatters results in angular spread. The point source model corresponding to discrete direction of arrival (DOA) becomes restrictive and leads to DOA estimation errors. To compensate for this effect, the distributed source model is proposed. In this paper, the coherently distributed source model is analysed. Based on that model, the accurate rotation matrix between the bases of the two signal subspaces is deduced. So an algorithm for the central DOA estimation of distributed sources is proposed based on unitary ESPRIT, which has an ESPRIT-like structure except for the fact that it is formulated in terms of real-valued computations throughout. The algorithm that has lower computational cost can be used for sources with different types of distribution function in MIMO channel. Simulations clearly demonstrate that the proposed method is not only effective, but also increases estimation accuracy compared with standard ESPRIT.