Joint Beamforming for STAR-RIS in Near-Field Communications

TL;DR

This paper introduces a joint beamforming approach for STAR-RIS in near-field MIMO communications, optimizing active and passive components to significantly enhance data rates.

Contribution

It proposes a novel joint optimization framework for STAR-RIS aided near-field MIMO, solving a complex non-convex problem with a BCD-based algorithm.

Findings

Near-field beamforming significantly improves weighted sum rate.

The proposed algorithm effectively optimizes active and passive beamforming.

Numerical results validate the performance gains of the method.

Abstract

A simultaneously transmitting and reflecting reconfigurable intelligent surface (STAR-RIS) aided near-field multiple-input multiple-output (MIMO) communication framework is proposed. A weighted sum rate maximization problem for the joint optimization of the active beamforming at the base station (BS) and the transmission/reflection-coefficients (TRCs) at the STAR-RIS is formulated. The resulting non-convex problem is solved by the developed block coordinate descent (BCD)-based algorithm. Numerical results illustrate that the near-field beamforming for the STAR-RIS aided MIMO communications significantly improve the achieved weighted sum rate.