Exploiting Pinching-Antenna Systems in Multicast Communications

TL;DR

This paper introduces a novel pinching-antenna system (PASS) that reconfigures wireless links to significantly enhance multicast rates, especially with more users and antennas, through optimized beamforming techniques.

Contribution

It develops closed-form solutions for single-waveguide scenarios and proposes AO algorithms for multi-PA and multi-waveguide cases, advancing multicast communication performance.

Findings

PASS outperforms fixed-location antennas in multicast rate.

Increasing PAs improves multicast performance.

PASS achieves higher rates with more users and coverage.

Abstract

The pinching-antenna system (PASS) reconfigures wireless links through pinching beamforming, in which the activated locations of pinching antennas (PAs) along dielectric waveguides are optimized. This article investigates the application of PASS in multicast communication systems, where pinching beamforming is designed to maximize the multicast rate. i) In the single-waveguide scenario, a closed-form solution for the optimal activated location is derived under the assumption of a single PA and linearly distributed users. Based on this, a closed-form expression for the achievable multicast rate is obtained and proven to be larger than that of conventional fixed-location antenna systems. For the general multiple-PA case with arbitrary user distributions, an element-wise alternating optimization (AO) algorithm is proposed to design the pinching beamformer. ii) In the multiple-waveguide scenario, an AO-based method is developed to jointly optimize the transmit and pinching beamformers. Specifically, the transmit beamformer is updated using a majorization-minimization (MM) framework together with second-order cone programming (SOCP), while the pinching beamformer is optimized via element-wise sequential refinement. Numerical results are provided to demonstrate that: i) PASS achieves significantly higher multicast rates than conventional fixed-location antenna systems, particularly when the number of users and spatial coverage increase; ii) increasing the number of PAs further improves the multicast performance of PASS.