Antenna Orientation Optimization for Rotatable Antenna-Enabled ISAC Systems

2026-06-30

AI Summary

This work addresses integrated sensing and communication (ISAC) systems with rotatable antennas, aiming to maximize the minimum echo signal power over an extended sensing region while satisfying multiuser communication rate requirements. To this end, the paper establishes a joint optimization framework for antenna pointing direction, communication beamforming, and sensing signal covariance matrix. A closed-form optimal solution is derived for the single-user point-target scenario, and an efficient alternating optimization algorithm is developed for the multiuser extended-target case. Simulation results demonstrate that the proposed approach significantly outperforms baseline schemes employing fixed antenna orientations or optimizing only array-level rotation, thereby achieving substantial improvements in both sensing and communication performance.

Abstract

Rotatable antenna (RA) has emerged as a promising technology to improve both communication and sensing performance in future wireless networks. In this paper, we deploy an RA array at the base station (BS) to improve the integrated sensing and communication (ISAC) performance by exploiting the additional spatial degrees of freedom (DoFs) introduced by antenna rotation. To enhance the sensing performance over an extended region containing a potential target while meeting the communication requirements of multiple users, we aim to maximize the minimum echo signal power within the sensing region, subject to required minimum communication rates of the users. For the special case of a single user and a point target, we show that the optimal orientation of all RAs is identical when both the communication user and the sensing target are located in the far-field region, and then derive a closed-form solution for the optimal RA pointing vector. For the general multi-user and extended-target case, we propose an alternating optimization (AO) algorithm that alternately optimizes the transmit beamforming for communication, the covariance matrix of the probing signal, and the pointing vectors of the RAs in an iterative manner. Simulation results demonstrate that the proposed RA-enabled ISAC system can significantly outperform various benchmark schemes, including systems with array-wise rotation optimization and fixed antenna orientation.

Problem

• Antenna Orientation Optimization
• Rotatable Antenna
• Integrated Sensing and Communication
• Spatial Degrees of Freedom
• Echo Signal Power

Innovation

• Rotatable Antenna
• Integrated Sensing and Communication (ISAC)
• Antenna Orientation Optimization
• Alternating Optimization
• Spatial Degrees of Freedom