PAPR Performance of Filter Shapes Index Modulation: Analysis and Optimization

Abstract

Filter Shapes Index Modulation (FSIM) is a novel single-carrier waveform scheme with increased spectral efficiency by utilizing different pulse-shaping filters to implicitly convey extra index bits. However, except for introducing inter-symbol interference (ISI), the high peak-to-average power ratio (PAPR) of the FSIM waveform, which can significantly impact the power efficiency of the FSIM system and counteract the achieved signal-to-noise ratio (SNR) gains, has not been investigated thus far. In this paper, we analyze the PAPR performance of the FSIM signaling and propose a PAPR reduction method based on filter bank optimization. And since the ISI constraint is relaxed in the process of optimization, an enhanced ISI reconstruction and cancellation scheme is also proposed to address the extra introduced ISI. Simulation results exhibit that, compared to the traditional single-carrier system, the proposed schemes reduce the PAPR of the FSIM signal and achieve 0.45 to 2 dB net SNR gains at different transmission rates under the multipath fading channel.