Efficient Pulse Shaping Waveforms for the RCP-OTFS Based UWAC System

Orthogonal Time Frequency Space (OTFS) modulation is a developing waveform intended to overcome the limitations of Orthogonal Frequency Division Multiplexing (OFDM) in high-mobility conditions. All the literature on the OTFS scheme tried in the underwater channel shows that OTFS-based UWAC achieves superior performance than the OFDM-based UWAC in terms of error performance and complexity of transmitter and receiver. However, most of the research is either limited to the ideal pulse shaping or rectangular pulse shaping in the case of practical pulses. So, the primary aim of this implementation work is to prolong the outcomes of the OTFS modulation with the more practical pulse-shaping waveforms. In this work, we first derive the input-output relationship between transmitted and received signals in the DD domain using practical pulse-shaping waveforms, such as rectangular pulses, in a simplified matrix form. Subsequently, extend this derivation to accommodate arbitrary waveform designs. Then, we compare the performance of the reduced cyclic prefix (RCP) OTFS-based UWAC system with different practical pulse-shaping waveforms. Simulation findings show that the OTFS system with the rectangular pulse shaping waveform outperforms the sine and the Hann window because of the uniform channel gain exposed to all transmitted symbols.