DFRC Signal Design With Hybrid Index Modulation

In this article, 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 signals by leveraging frequency diversity, time diversity, and intrapulse index modulation (InM) for information embedding. This enables multiuser 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 a 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 scenarios. Additionally, the simulations affirm the feasibility of our method in multiuser communication scenarios.