On the Performance of Nonlinear Corrective Active Constellation Expansion in OTFS Systems

Abstract

Orthogonal time frequency space (OTFS) modulation has been put forward to achieve better performances over delay-Doppler channels in comparison with orthogonal frequency division multiplexing (OFDM) systems. In this letter, a nonlinear corrective active constellation expansion (NC-ACE) method is firstly proposed in OTFS waveform to achieve precise control of peak-to-average power ratio (PAPR) and BER performances due to its nonlinear compression characteristics. Compared to linear constraint of clipping and filtering process in traditional active constellation expansion (ACE) and bounded distortion ACE (BD-ACE) strategies, nonlinear compressed clipping noise is considered with a flexible curvature control coefficient. According to flexible features of NC-ACE, a bridge between optimal suppression and no reduction of PAPR performances is established in OTFS systems, where tradeoff between PAPR and BER performances can be further obtained.