DFRC signal design with hybrid index modulation

In this paper, a novel Hybrid Index Modulation (HInM) strategy is proposed in a dual-use signal design for a phased-array based Dual Function Radar Communication (DFRC) system. The HInM approach maximizes the Degrees of Freedom (DoFs) inherent in dual-use signal by leveraging frequency diversity, time diversity, and intra-pulse index modulation for information embedding. This enables multi-user communication, accommodating receivers located in both the sidelobe and mainlobe regions. To preserve detection performance, the Peak Sidelobe Level (PSL) of the dual-use signal autocorrelation function is minimized with constant-envelope and modulation constraints. Addressing the resulting nonconvex and NP-hard optimization challenge, we propose an Fast Majorization-Minimization (FMM) algorithm within the Majorization-Minimization (MM) framework. Simulation results validate the effectiveness of our proposed technique, showcasing effective detection performance and significant data rate enhancement compared to existing techniques in broadcasting communication scenario. Additionally, the simulations affirm the feasibility of our method in multi-user communication scenario.