Integrated Sensing and Communication Beamforming Design Based on Mutual Information

TL;DR

This paper proposes novel beamforming strategies for integrated sensing and communication systems, optimizing radar mutual information and communication rate with low complexity solutions and SDR-based methods.

Contribution

It introduces closed-form and SDR solutions for ISAC beamforming design, enhancing efficiency and providing optimal and tight solutions.

Findings

Closed-form solution is tight within the feasible region.

SDR method achieves an optimal solution.

Proposed methods improve spectrum and energy efficiency.

Abstract

Integrated sensing and communication (ISAC) unifies radar sensing and communication, and improves the efficiency of the spectrum, energy and hardware. In this paper, we investigate the ISAC beamforming design in a downlink system with a communication user and a point radar target to be perceived. The design criterion for radar sensing is the mutual information between the target response matrix and the echo signals, while the single user transmission rate is used as the performance metric of the communication. Two scenarios without and with interference from the communication user are investigated. A closed-form solution with low complexity and a solution based on the semidefinite relaxation (SDR) method are provided to solve these two problems, respectively. Numerical results demonstrate that, compared to the results obtained by SDR based on the CVX toolbox, the closed-form solution is tight in the feasible region. In addition, we show that the SDR method obtains an optimal solution.