Transmit Hardware Impairment Aware Waveform Design for MIMO DFRC

In this paper, we address the problem of waveform design for multiple-input multiple-output (MIMO) dual-functional radar-communication (DFRC) system in the presence of transmit hardware impairments. Under this scenario, the actual transmit waveform is a distorted version of the expected waveform, and thus may lower system performance. To achieve robustness against distortion in the waveform design, the worst-case radar and communication performance metrics are derived as the optimization criteria. For the radar side, we maximize the minimum-mainlobe-to-peak-sidelobe-level ratio (MMPSLR) to its worst-case metric for synthesized beampattern and spatial-spectrum to avoid specifying a mask that can be improper or even unreachable. In order to design dual-functional waveform with or without spectral compatibility, two different formulations are established. Both have complicated non-convex fractional constraints, and the resultant optimization problems are tackled with the use of alternating direction method of multipliers. Numerical results demonstrate the effectiveness of our algorithms to attain stronger robustness against transmit hardware impairments, synthesize a beampattern with larger MMPSLR compared with benchmarks, while spectral compatibility is also guaranteed.