Reduction of Peak-to-Average Power Ratio in Transform Domain Communication Systems

Transform Domain Communication Systems (TDCS) are spectrum-scavenging systems which modulate data by a waveform whose magnitude is non-zero only in unused frequency bins, and whose phase is pseudo-random. This creates a noise-like waveform suitable for secure, low probability of intercept (LPI) communications, as well as spectrum-sharing applications. However, it also creates a high peak-to-average power ratio (PAPR). We investigate PAPR reduction in TDCS by modifying the projection onto complex sets approach for multicarrier systems. Simulations show that adequate PAPR reduction is achieved, transmitter-receiver waveform mismatches are not exacerbated by PAPR reduction, and the resulting waveform is still LPI.