Time-Modulated OFDM-IM Directional Modulation Antenna Array Transmitters

Orthogonal frequency-division multiplexing (OFDM) directional modulation (DM) has been well studied in securing multicarrier signals in physical-layer wireless communications. However, it suffers from the high peak-to-power ratio (PAPR) issue. In this paper, combining the DM concept with OFDM with index modulation, by using the time-modulated array (TMA), the OFDM-IM DM symbols are synthesized, which enjoy enhanced secrecy performance and meanwhile can alleviate the pressure of high PAPR. This is demonstrated by the bit error rate (BER) metric via the simulation results. The proposed OFDM-IM DM waveforms here could be a potential technique for joint Radar and Communication (JRC).