Revealing the Impact of Beamforming in ISAC

TL;DR

This paper investigates how advanced beamforming affects sensing and communication performance in a single-user ISAC system, deriving closed-form solutions for different design scenarios and analyzing their impact on key performance metrics.

Contribution

It introduces novel closed-form beamformers for various ISAC scenarios and provides a comprehensive analysis of their impact on system performance metrics.

Findings

Beamforming design influences high-SNR power offset and diversity order.

ISAC outperforms FDSAC in high-SNR slopes and SR-CR region.

High-SNR slope remains unaffected by beamforming design.

Abstract

This letter proposes advanced beamforming design and analyzes its influence on the sensing and communications (S&C) performance for a multiple-antenna integrated S&C (ISAC) system with a single communication user and a single target. Novel closed-form beamformers are derived for three typical scenarios, including the sensing-centric design, communications-centric design, and Pareto optimal design. Regarding each scenario, the outage probability, ergodic communication rate (CR), and sensing rate (SR) are analyzed to derive the diversity orders and high signal-to-noise ratio slopes. Numerical results are provided to demonstrate that i) beamforming design can affect the high-SNR power offset and diversity order but does not influence the high-SNR slope; ii) ISAC exhibits larger high-SNR slopes and a more extensive SR-CR region than conventional frequency-division S&C (FDSAC) techniques.