Exploiting Movable Antennas in Multicast Communications

TL;DR

This paper introduces a novel multicast communication system utilizing movable antennas, optimizing their placement and beamforming to significantly improve multicast rates through advanced algorithms and analysis.

Contribution

It proposes a new MA-assisted multicast architecture with optimization algorithms for antenna placement and beamforming, including closed-form solutions and global optimality under LOS conditions.

Findings

Enhanced multicast rate with proposed algorithms

Effective antenna placement and beamforming optimization

Global optimality achieved in LOS environments

Abstract

This article investigates the integration of movable antennas (MAs) into multicast communication systems. By discretizing the motion of the MAs, a novel MA-assisted multicast transmission architecture is formulated. An alternating optimization (AO) algorithm based on successive convex approximation is proposed to optimize the transmit beamforming and antenna positions. To gain further insights, the two-user case is examined, and a closed-form expression for the optimal beamformer is derived. On this basis, a low-complexity greedy search algorithm is developed to optimize the placement of the MAs. Furthermore, under the assumption of a line-of-sight propagation environment, a branch-and-bound algorithm is designed to determine the globally optimal antenna configuration with reduced complexity compared to exhaustive search. Numerical simulations confirm that the proposed methods effectively enhance the achievable multicast rate.