Enhancing the WLAN OFDM-PHY by OTFS Precoding

Reliable communication in high-mobility scenarios is considered a significant challenge. For such a problematic task, the Orthogonal Time Frequency Space (OTFS) modulation technique has come up as an efficient solution, providing promising results in doubly selective time and frequency channels. In this paper, we have simulated and compared OTFS and a complete Orthogonal Frequency-Division Multiplexing (OFDM) system in a multipath environment at different mobile speeds under the presence of a synchronization impairment, i.e., timing offset (TO). Firstly, we have modelled the OTFS system according to the active subcarriers in the OFDM system and then modified the OTFS frame in the time-frequency (TF) plane in compliance with the OFDM symbol. This modification kept a similar bandwidth for both systems, eliminated the need for multi-rate processing and allowed OTFS to be used as a precoder to the targeted OFDM transceiver. Our simulation results show that, with increased mobility, the OFDM Error Vector Magnitude (EVM) performance is degraded abruptly, whereas the OTFS link remains stable.