Computationally Efficient Two-dimensional-DOA Estimation for Massive MIMO Uplink

In this paper, an weighted subspace fitting and oblique projection based algorithm is proposed to deal with the two-dimensional direction-of-arrival (DOA) estimation of multipath signals over the massive multiple-input multiple-output (MIMO) uplink. The whole procedures include three steps: one marginal DOA information of all uncorrelated and coherent multipath signals is first acquired by minimizing a reduced-dimensional weighted subspace fitting function; subsequently, the uncorrelated DOA among the above results is discerned and their auto-paired steering vectors with respect to the other marginal DOA are derived by closed-form expressions; finally, an virtual array observation is constructed via a new Toeplitz-structured oblique projector to assist the other marginal DOA estimation of the coherent multipath signals. Compared with some exist algorithms by numerical simulations, the proposed one performs better from the united perspective of computational complexity and estimation accuracy, therefore it can be served as a better alternative to the competitors.