Design of Constraint FH-LFM DFRC Waveform

An efficient spectrum sharing method is urgent for the increasing demand for frequency resources. Dual-functional radar-communication (DFRC) is expected to efficiently share the spectrum by minimizing performance deterioration. Existing DFRC waveforms based on radar waveform designs result in out-of-band leakage, high receiver complexity and high symbol error rate (SER). In this paper, we propose a DFRC waveform based on constrained frequency hopping (FH) and linear frequency modulation (C-FH-LFM). The FH sequence for the chips and positive/negative frequency modulation slope are adopted to embed the communication information, achieving a single frequency traversal within a single pulse. We give explicit rules of FH sequence to reduce the storage and processing of the matching signal and reduce the SER at receiver. Then, we derived the range of the time-bandwidth product and the upper limit of the distributable chip number, which is universal in modulation systems by positive/negative LFM slope. The simulation results show that, the proposed C-FH-LFM waveform reduces out-of-band power leakage of 12 dB compared with phase shift keying scheme, and provides 6 dB improvement of SNR under the same SER compared with unconstrained FH-LFM scheme.