Low complexity hybrid precoding based on ORLS for mmWave massive MIMO systems

Abstract

Orthogonal matching pursuit (OMP) and its improved algorithms are widely used as hybrid precoding solutions in millimeter wave massive MIMO systems. The existing modified hybrid precoding schemes reduce computational complexity, however, they cause the loss of spectral efficiency to some extent. In this paper, we propose a novel generalized orthogonal matching pursuit (gOMP) algorithm based on order-recursive least squares (ORLS) in order to balance both computational cost and spectral efficiency. Compared to OMP algorithm, the maximum iteration of gOMP-ORLS algorithm can be reduced by choosing more than one vector in each iteration. Meanwhile, it has much lower implementation complexity due to avoiding matrix inversion operation. More importantly, the realized spectral efficiency of the proposed algorithm is higher than other existing algorithms. The simulation results as well as our detailed analysis demonstrate that a) the proposed gOMP-ORLS algorithm can achieve the approximately same spectral efficiency as OMP algorithm; b) it can reduce computational complexity and improve precoding efficiency prominently.