Weighted Sum Rate Optimization for Movable Antenna Enabled Near-Field ISAC

TL;DR

This paper develops an algorithm to optimize weighted sum rate in movable antenna-enabled near-field ISAC systems, enhancing communication and sensing performance through joint antenna positioning and beamforming.

Contribution

It introduces a novel joint optimization algorithm for antenna positions, sensing, and communication parameters in near-field ISAC with movable antennas.

Findings

Movable antennas significantly improve near-field ISAC performance.

Optimal WSR is achieved with higher weights for closer users.

Sensing performance is more sensitive to SINR thresholds than communication.

Abstract

Integrated sensing and communication (ISAC) has been recognized as one of the key technologies capable of simultaneously improving communication and sensing services in future wireless networks. Moreover, the introduction of recently developed movable antennas (MAs) has the potential to further increase the performance gains of ISAC systems. Achieving these gains can pose a significant challenge for MA-enabled ISAC systems operating in the near-field due to the corresponding spherical wave propagation. Motivated by this, in this paper we maximize the weighted sum rate (WSR) for communication users while maintaining a minimal sensing requirement in an MA-enabled near-field ISAC system. To achieve this goal, we propose an algorithm that optimizes the sensing receive combiner, the communication precoding matrices, the sensing transmit beamformer and the positions of the users' MAs in an alternating manner. Simulation results show that using MAs in near-field ISAC systems provides a substantial performance advantage compared to near-field ISAC systems with only fixed antennas. Additionally, we demonstrate that the highest WSR is obtained when larger weights are allocated to the users placed closer to the BS, and that the sensing performance is significantly more affected by the minimum sensing signal-to-interference-plus-noise ratio (SINR) threshold compared to the communication performance.