Suppression Method for PAPR in TDCS Based on Convex Set Mapping and Peak Reduction

Transform domain communication system (TDCS) can dynamically sense its spectrum environment and actively avoid interferences, thereby realizing the efficient transmission of spectrum aggregation in complex electromagnetic environments. However, the problem of peak-to-average power ratio (PAPR) is unavoidable because the TDCS basis function, when generated, requires an inverse fast Fourier transform (IFFT). A compromise between the suppression degree of PAPR and the bit error rate (BER) loss is achieved by traditional methods. In this study, a method of approximate projection onto complex sets (APOCS) was proposed to effectively suppress the PAPR of the TDCS system by setting the clip level and iteration times, without introducing the BER loss. On this basis, a peak reduction technique of phase cancellation (PRPC) is further proposed. Simulation results show that the APOCS can be suppressed by over 6 dB through over 10 iterations, and PRPC can obtain a performance close to constant envelopes with certain bit error rate loss.