Multiuser Communications with Movable-Antenna Base Station Via Antenna Position Optimization

TL;DR

This paper proposes an optimization framework for movable antennas at the base station to enhance multiuser uplink communication rates by jointly optimizing antenna positions, receive combining, and user transmit power.

Contribution

It introduces a novel antenna position optimization method using particle swarm optimization and block coordinate descent for multiuser communication performance enhancement.

Findings

Significant rate improvements over fixed-position antennas.

Effective joint optimization of antenna positions, receive combining, and power.

Demonstrated the benefits of movable antennas in multiuser scenarios.

Abstract

This paper studies the deployment of multiple movable antennas (MAs) at the base station (BS) for enhancing the multiuser communication performance. First, we model the multiuser channel in the uplink to characterize the wireless channel variation caused by MAs' movement at the BS. Then, an optimization problem is formulated to maximize the minimum achievable rate among multiple users for MA-aided uplink multiuser communications by jointly optimizing the MAs' positions, their receive combining at the BS, and the transmit power of users, under the constraints of finite moving region of MAs, minimum inter-MA distance, and maximum transmit power of each user. To solve this challenging non-convex optimization problem, a two-loop iterative algorithm is proposed by leveraging the particle swarm optimization (PSO) method. Specifically, the outer-loop updates the positions of a set of particles, where each particle's position represents one realization of the antenna positioning vector (APV) of all MAs. The inner-loop implements the fitness evaluation for each particle in terms of the max-min achievable rate of multiple users with its corresponding APV, where the receive combining matrix of the BS and the transmit power of each user are optimized by applying the block coordinate descent (BCD) technique. Simulation results show that the antenna position optimization for MAs-aided BS can significantly improve the rate performance as compared to conventional BS with fixed-position antennas (FPAs).