Work

Low-Complexity Cramér-Rao Lower Bound and Sum Rate Optimization in ISAC Systems

Year: 2025
Type: conference-paper
Abstract: While Cramér-Rao lower bound is an important metric in sensing functions in integrated sensing and communications (ISAC) designs, its optimization usually involves a computationally expensive solution such as semidefinite relaxation. In this paper, we aim to develop a low-complexity yet efficient algorithm for CRLB optimization. We focus on a beamforming design that maximizes the weighted sum between the communications sum rate and the sensing CRLB, subject to a transmit power constraint. Given the non-convexity of this problem, we propose a novel method that combines successive convex approximation (SCA) with a shifted generalized power iteration (SGPI) approach, termed SCA-SGPI. The SCA technique is utilized to approximate the non-convex objective function with convex surrogates, while the SGPI efficiently solves the resulting quadratic subproblems. Simulation results demonstrate that the proposed SCA-SGPI algorithm not only achieves superior tradeoff performance compared to existing method but also significantly reduces computational time, making it a promising solution for practical ISAC applications.
Authors: Tianyu Fang, Nhan Thanh Nguyen, Markku Juntti
Institution: University of Oulu
Language: English
Open Access status: green
OpenAlex ID: W4408345872
FWCI: 28.07
Cites: 26
Cited by: 11
Related to: 10