Achieving the Optimal Transceiver Beamforming for Multi-User and Multi-Target DFRC System

As an effective way to realize the integrated sensing and communication for 6G, the dual-functional radar-communication (DFRC) has been studied to implement dual-functional system that simultaneously perform wireless communication and radar sensing. One of the fundamental design issues in DFRC focuses on waveform design, including the selection of basic waveform (e.g., Orthogonal Time Frequency Space (OTFS) or Orthogonal Frequency Division Multiplexing (OFDM)), and the optimal beamforming design. In this paper, we investigate the transceiver beamforming design for a multi-input-multi-output (MIMO) DFRC system, where the dual functional base station (BS) simultaneously detects the multiple targets while communicating with multiple communication users. To this end, we first characterize the multi-fold tradeoffs between communication and radar sensing by defining an achievable performance region of the proposed DFRC system. The performance of communication and radar sensing are characterized by their signal-to-interference-plus-noise ratios (SINRs), and then the multi-objective optimization problem is formulated to maximize the SINRs of all communication users and radar sensing echoes (from targets) via optimizing beamforming matrix. To solve the problem, we propose a poly-complexity solution by using the quadratic transform and successive convex approximation. Simulation results are provided to verify the proposed design.