Transmission Waveform Design of MIMO Dual-Functional Radar-Communication System

Based on the multiple-input multiple-output (MIMO) dual-functional radar-communication (DFRC) system, a new DFRC transmission waveform is designed in this paper, The MIMO-DFRC system transmits radar detection waveform to targets and communication signals to downlink users simultaneously using orthogonal frequency division multiplexing (OFDM) chirp multi-channel orthogonal signals. Firstly, considering the key performance indicators of communication and sensing, an optimization model is established to minimize the joint function of downlink multi-user interference (MUI), waveform similarity and CRB under the constraint of total transmit power, and the tradeoff parameter is introduced to adjust the priority of communication and radar performance, and the penalty parameter is introduced to adjust the weight of reference waveform similarity and CRB. The constrained optimization problem can be further reduced to a non-convex quadratic constrained quadratic programming problem, which can be solved by semidefinite relaxation (SDR) technique. The global optimal solution can be obtained by transforming the constrained optimization problem into a semi-definite programming problem (SDP) by rank one approximation. The numerical results show that the designed DFRC transmission waveform can achieve better detection performance without sacrificing the communication performance in the real scenario, and the performance indicators of the new DFRC transmission waveform are significantly better than that of the traditional DFRC transmission waveform.