OTFS: Interleaved OFDM with Block CP
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Orthogonal time frequency space (OTFS) modulation is a recently proposed waveform for reliable communication in high-speed vehicular communications. It has better resilience to inter-carrier interference (ICI) as compared to orthogonal frequency division multiplexing (OFDM). In OTFS, information is generated in the Doppler-delay domain as opposed to time-frequency domain in conventional OFDM. In this work, we describe OTFS as block-OFDM with a cyclic prefix and time interleaving. Through this description, we explained the improved performance of OTFS over OFDM. We also compare the performance of OTFS against its contender 5G new radio (NR)'s OFDM configuration of variable subcarrier bandwidth (VSB) while considering practical forward error correction codes and 3GPP high-speed channel model. We have considered practical channel estimates in the demodulation and find that OTFS outperforms VSB with 5G NR parameter. We also study the influence of pilot in OTFS in its peak to average power ratio (PAPR).
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