Discrete fourier transform spread zero word OFDM

Abstract

Fifth generation (5G) waveform must meet a superior performance in multipath channels along with low peak to average power ratio (PAPR), especially in up-link transmission. Among waveform candidates, zero tail (ZT) DFT-spread (s) OFDM has low PAPR. However, unlike its name, ZT-DFT-s-OFDM contains non-zero samples at its tails causing inter-symbol interference (ISI) in multipath channels. In this paper, we utilize redundant subcarriers concept in unique word (UW) OFDM to nullify the tail of ZT DFT-s-OFDM. The achieved waveform called 'DFT Spread (s) Zero Word (ZW) OFDM' benefits from high mitigation in the ISI compared to ZT DFT-s-OFDM. The remaining benefits in this approach include: (I) around 3 dB performance improvement in Bit Error Rate (BER) compared to cyclic prefix (CP)-OFDM in time dispersive channels, (II) around 0.7 dB lower PAPR compared to CP-OFDM and UW OFDM, (III) having a flexible guard interval length in IFFT output intrinsically. In order to support above claims, simulation results are provided which depict the accuracy and enhanced performance of the proposed waveform compared to the mentioned waveform candidates.