Research Of Direction-of-arrival Estimation Based On Propagator Method In Massive MIMO Systems

Massive MIMO(Multiple Input Multiple Output)technology is one of the important technologies of the fifth generation of wireless communication.It can significantly increase the channel capacity and spectrum efficiency without increasing the spectrum resources and transmit power.However,system performance of multiple cells may be severely disturbed by inter-cell interference in massive MIMO systems.Beamforming techniques can suppress the interference.In order to implement beamforming techniques,accurate DOA information of the signals must be obtained.The existing DOA algorithms have the problems of high complexity and heavy computation.Therefore,this paper studies the PM algorithm with high-performance and low-complexity that is applied in massive MIMO systems.The innovation points are as follow:(1)In the massive ULA,the traditional PM algorithm is implemented based on subspace decomposition and rotation invariance;The performance of the PM algorithm is poor for low SNR and small snapshots,so this paper proposes the conjugate orthogonal PM algorithm(G-OPM).This paper proposes an OPM algorithm(HXG-OPM)based on the cross-correlation Toeplitz matrix reconstruction for the PM algorithm can't correctly estimate the coherent signal,and verifies these new algorithms by the simulations.(2)In the massive URA,a 2D-PM algorithm is implemented based on subspace decomposition and rotation invariance.In this paper,it proposes a PM algorithm based on beam space transformation for it has a large amount of computation in massive MIMO systems,further reducing the complexity of the PM algorithm.Finally,the new algorithm is applied to line array and area array and verified by the simulations.