Gram Schmidt Based Greedy Hybrid Precoding for Frequency Selective Millimeter Wave MIMO Systems

TL;DR

This paper introduces a low-complexity greedy hybrid precoding algorithm for frequency selective millimeter wave MIMO systems, utilizing Gram-Schmidt orthogonalization to select RF beamforming vectors from a quantized codebook, achieving near-optimal performance.

Contribution

It presents a novel greedy algorithm for frequency selective hybrid precoding that is computationally efficient and performs close to unconstrained solutions.

Findings

Achieves near-optimal precoding performance

Reduces computational complexity compared to existing methods

Effective in frequency selective mmWave MIMO channels

Abstract

Hybrid analog/digital precoding allows millimeter wave MIMO systems to leverage large antenna array gains while permitting low cost and power consumption hardware. Most prior work has focused on hybrid precoding for narrow-band mmWave systems. MmWave systems, however, will likely operate on wideband channels with frequency selectivity. Therefore, this paper considers frequency selective hybrid precoding with RF beamforming vectors taken from a quantized codebook. For this system, a low-complexity yet near-optimal greedy algorithm is developed for the design of the hybrid analog/digital precoders. The proposed algorithm greedily selects the RF beamforming vectors using Gram-Schmidt orthogonalization. Simulation results show that the developed precoding design algorithm achieves very good performance compared with the unconstrained solutions while requiring less complexity.