Fast Fractional Programming for Multi-Cell Integrated Sensing and Communications

Abstract

This paper concerns the coordinate multi-cell beamforming design for integrated sensing and communications (ISAC). In particular, we assume that each base station (BS) has massive antennas. The optimization objective is to maximize a weighted sum of the data rates (for communications) and the Fisher information (for sensing). We first show that the conventional beamforming method for the multiple-input multiple-output (MIMO) transmission, i.e., the weighted minimum mean square error (WMMSE) algorithm, works for the ISAC problem case from a fractional programming (FP) perspective. However, the WMMSE algorithm frequently requires computing the $N\times N$ matrix inverse, where $N$ is the number of transmit or receive antennas, so the algorithm becomes quite costly when antennas are massively deployed. To address this issue, we develop a nonhomogeneous bound and use it in conjunction with the FP technique to solve the ISAC beamforming problem without the need to invert any large matrices. It is further shown that the resulting new FP algorithm has an intimate connection with gradient projection, based on which we can accelerate the convergence via Nesterov's gradient extrapolation.

17 pages

References in corpus (13)

• Joint Transmit Beamforming for Multiuser MIMO Communication and MIMO Radar
• Cramér-Rao Bound Optimization for Joint Radar-Communication Design
• Fractional Programming for Communication Systems--Part II: Uplink Scheduling via Matching
• Joint Radar-Communications Strategies for Autonomous Vehicles
• Content-Centric Sparse Multicast Beamforming for Cache-Enabled Cloud RAN
• Throughput Maximization for UAV-enabled Integrated Periodic Sensing and Communication
• MAJoRCom: A Dual-Function Radar Communication System Using Index Modulation
• STARS Enabled Integrated Sensing and Communications
• Intelligent Reflecting Surface Enabled Sensing: Cramér-Rao Bound Optimization
• SNR/CRB-Constrained Joint Beamforming and Reflection Designs for RIS-ISAC Systems
• Rethinking WMMSE: Can Its Complexity Scale Linearly With the Number of BS Antennas?
• Mixed Max-and-Min Fractional Programming for Wireless Networks
• Flexible Multiple Base Station Association and Activation for Downlink Heterogeneous Networks