Multi-Antenna Joint Radar and Communications: Precoder Optimization and Weighted Sum-Rate vs Probing Power Tradeoff

TL;DR

This paper introduces two novel transmission techniques for joint multi-antenna radar-communication systems, optimizing precoders to balance weighted sum-rate and probing power, with shared deployment showing superior radar beamforming performance.

Contribution

It proposes separated and shared antenna deployment methods for RadCom systems, employing SDP and MM algorithms for optimization, and compares their performance and tradeoffs with simpler dual-function schemes.

Findings

Shared deployment outperforms separated deployment in radar beamforming.

Shared deployment surpasses time division in certain conditions.

Separated deployment enables spectrum sharing but with some performance loss.

Abstract

In order to further exploit the potential of joint multi-antenna radar-communication (RadCom) system, we propose two transmission techniques respectively based on separated and shared antenna deployments. Both techniques are designed to maximize the weighted sum rate (WSR) and the probing power at target's location under average power constraints at the antennas such that the system can simultaneously communicate with downlink users and detect the target within the same frequency band. Based on a Weighted Minimized Mean Square Errors (WMMSE) method, the separated deployment transmission is designed via semidefinite programming (SDP) while the shared deployment problem is solved by majorization-minimization (MM) algorithm. Numerical results show that the shared deployment outperforms the separated deployment in radar beamforming. The tradeoffs between WSR and probing power at target are compared among both proposed transmissions and two practically simpler dual-function implementations i.e., time division and frequency division. Results show that although the separated deployment enables spectrum sharing, it experiences a performance loss compared with frequency division, while the shared deployment outperforms both and surpasses time division in certain conditions.