Low-Complexity Hybrid Precoding for Subarray Architecture mmWave MIMO Systems

Hybrid precoding for millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems has attracted much attention in recent years subarray architecture compared to array because of its low cost and power consumption. This is due the small number required phase shifters architecture. In this paper, we investigate issue hybrid narrowband mmWave MIMO systems. First, derive spectral efficiency with discuss problem formulation. Then, propose two low-complexity algorithms first algorithm, matrix divided into subarrays submatrices each submatrix then vectors. The analog determined from vector submatrix, which used determine elements digital precoder all vectors (vector by vector) using a simple maximum ratio combining (MRC) method. proposed algorithm called vector-by-vector (VBV) precoding. Finally, further enhance system performance, VBV also combined an iterative solution, resulting precoder. Simulation results verify that outperform successive interference cancellation-based performance close obtained fully-connected spatially sparse various settings, lower complexity.