@article{M761E4F0B,
title = "Fractional Programming for Multi-User ISAC Beamforming Design: A Bayesian CRB Perspective",
journal = "The Journal of Korean Institute of Communications and Information Sciences",
year = "2025",
issn = "1226-4717",
doi = "10.7840/kics.2025.50.9.1397",
author = "Seok-Hwan Park",
keywords = "Integrated sensing and communication, Multi-user, beamforming, fractional programming, , Bayesian CRB",
abstract = "Integrated sensing and communication (ISAC) is a promising paradigm for sixth-generation (6G) wireless networks, enabling spectrum-efficient coexistence of sensing and communication functionalities. This paper investigates ISAC beamforming optimization for a multi-user system, where a base station (BS) serves multiple communication user equipments (C-UEs) while sensing a target of interest. We adopt the Bayesian Cramer-Rao bound (BCRB) as the sensing performance metric, which is a expected value of CRB with respect to the target prior distribution. An optimization problem is formulated to minimize the BCRB while ensuring that C-UEs’ signal-to-interference-plus-noise ratios (SINRs) exceed predefined thresholds. To address the inherent non-convexity, we employ the fractional programming (FP), leading to a structured reformulation that enables efficient optimization. An alternating optimization (AO) algorithm is developed to iteratively update the primary beamforming and auxiliary variables, ensuring monotonic decrease of BCRB values. Numerical results validate the effectiveness of the proposed FP approach, demonstrating improved sensing accuracy while maintaining reliable communication performance."
}