Soft-Decision Multiple Access TDCS and PAPR Reduction

Abstract

As a candidate of overlay cognitive radio (CR), transform domain communication system (TDCS) can achieve dynamic spectrum access by avoiding existing users and interference spectrum bins. However, in poor channel conditions, traditional TDCS cannot maintain low probability of interception (LPI) and covert communication capability at the same time. A TDCS structure of designing the fundamental modulation waveform (FMW) with a soft-decision (SD) method is presented in this paper. To reduce peak-to-average power ratio (PAPR) of SD-TDCS, an algorithm which designs the low-sidelobe FMWs under spectrum constrains is proposed. Simulation results demonstrate that the proposed SD-TDCS architecture can improve BER performance and anti-interference ability. And adequate PAPR reduction is achieved with the proposed waveform design algorithm.