Index Modulation with Circularly-Shifted Chirps for Dual-Function Radar and Communications

In this study, we propose index modulation (IM) with circularly-shifted chirps (CSCs) (CSC-IM) for dual-function radar and communication (DFRC) systems. The proposed scheme encodes the information bits CSC indices phase-shift keying (PSK) symbols. It allows receiver to exploit frequency selectivity naturally in fading channels by combining IM wideband CSCs. also leverages fact that a is constant-envelope signal achieve controllable peak-to-mean envelope power ratio (PMEPR). For functionality, CSC-IM maintains good autocorrelation (AC) properties of chirp ensuring transmitted CSCs are separated apart sufficiently time domain through separation (IS). We investigate impact IS on spectral efficiency (SE) obtain corresponding mapping functions. theoretical results, derive union bound (UB) block error rate (BLER) arbitrary Cramer-Rao lower bounds (CRLBs) range reflection coefficients matched filter (MF)- based estimation. prove complementary sequences (CSs) can be constructed linearly Fourier series Finally, comprehensive comparisons, demonstrate efficacy DFRC scenarios.