Bistatic MIMO DFRC System Waveform Design via Symbol Distance/Direction Discrimination

In this article, we address the problem of waveform design for bistatic multiple-input multiple-output dual-function radar-communication system with focuses on both the multi-user interference based symbol error rate (SER) of the communication side and the Cramér-Rao lower bounds (CRLBs) for direction-of-departure (DOD) and direction-of-arrival (DOA) of target from the radar side. Particularly, we minimize the maximal ratio of the error distances from desired symbols to the distances from undesired symbols, referred to as 'discriminant' distances, to enhance the separability of received symbols, which in turn improves the SER. While we derive two CRLB constraints on DOD and DOA separately as the semi-definite programming formulations to avoid complex computation from fractional constraints via constructing two special positive semi-definite matrices. Moreover, the aforementioned 'distance-similarity'-based metric is extended to the 'direction-similarity'-based metric. Numerical results demonstrate the effectiveness of our proposed communication metrics and design solutions in terms of SER performance and robustness against non-linear phase-noise compared with the competing methods.