Joint Design of Transmit Beamforming and Receive Filters for MIMO ISAC Systems Under Low-Altitude Dynamic Scenarios

This paper investigates the joint transmit beamforming and receive filters design for multiple-input multiple-output integrated sensing and communication (MIMO ISAC) systems serving multiple users and low-altitude dynamic targets. We aim to minimize multi-user interference subject to total and per-user power budgets, sensing signal-to-interference-plus-noise ratio (SINR) thresholds, and two-dimensional Cramér–Rao lower bound (CRLB) constraints for target estimation. To tackle the highly nonconvex CRLB constraints, we reformulate them into tractable semidefinite programming (SDP) forms. An alternating optimization framework is then proposed, in which receive filters are updated via closed-form minimum variance distortionless response (MVDR) solutions, while transmit beamforming is optimized using an alternating direction penalty method (ADPM). Theoretical analysis establishes the computational complexity and guarantees convergence to a stationary solution. Numerical results demonstrate that the proposed algorithm outperforms the alternating direction method of multipliers (ADMM) benchmark, achieving faster convergence and lower objective values.