Switch-based Hybrid Beamforming for Wideband Multi-carrier Communications

TL;DR

This paper investigates switch-based hybrid beamforming for wideband multi-carrier MIMO systems, addressing beam squint effects and proposing tabu search algorithms to optimize spectral efficiency and energy efficiency.

Contribution

It introduces a tabu search-based design for switch-based hybrid beamforming that mitigates beam squint and enhances performance over phase-shifter-based methods.

Findings

SW-HBF significantly reduces beam squint effects.

Proposed algorithms achieve near-optimal spectral efficiency.

SW-HBF outperforms PS-HBF in energy efficiency.

Abstract

Switch-based hybrid beamforming (SW-HBF) architectures are promising for realizing massive multiple-input multiple-output (MIMO) communications systems because of their low cost and low power consumption. In this paper, we study the performance of SW-HBF in a wideband multi-carrier MIMO communication system considering the beam squint effect. We aim at designing the switch-based combiner that maximizes the system spectral efficiency (SE). However, the design problem is challenging because the analog combing matrix elements are binary variables. To overcome this, we propose tabu search-based (TS) SW-HBF schemes that can attain near-optimal performance with reasonable computational complexity. Furthermore, we compare the total power consumption and energy efficiency (EE) of the SW-HBF architecture to those of the phase-shifter-based hybrid beamforming (PS-HBF) architecture. Numerical simulations show that the proposed algorithms can efficiently find near-optimal solutions. Moreover, the SW-HBF scheme can significantly mitigate the beam squint effect and is less affected by the number of subcarriers than PS-HBF. It also provides improved SE and EE performance compared to PS-HBF schemes.