diversity (that is, variation of channel with time) to improve the reliability of wireless links [4]. This waveform was first introduced in the pioneering work of Hadani et al. [4] where the two-dimensional (2D) delay-Doppler domain was proposed for multiplexing the transmit data. OTFS modulation is a gener- alized signaling framework where precoding and post-processing units are added to the modulator and demodulator of a multicarrier waveform allowing for taking advantage of full time and frequency diversity gain of doubly dispersive channels. This process also converts the time-varying channel to a time-invariant one in the delay-Doppler domain. In OTFS, transmit data symbols are treated as the values of the regularly spaced grid points in delay-Doppler plane. A transformation step takes each data symbol and spreads Radio Access Network Slicing and Virtualization for 5G Vertical Industries, First Edition. Edited by Lei Zhang, Arman Farhang, Gang Feng, and Oluwakayode Onireti. © 2021 John Wiley & Sons Ltd. Published 2021 by John Wiley & Sons Ltd. 6 Orthogonal Time-Frequency Space Modulation: Principles and Implementation it over the entire time-frequency plane. The result of this transformation is then passed to a multicarrier system for modulation and transmission. In this way, all data symbols are equally affected by the channel frequency selectivity and time diversity and, as a result, the time-varying channel, with a good approximation, converts to a unified time-invariant impulse response for all the data symbols in delay-Doppler domain. To recover the trans- mitted data symbols at the receiver, the respective multicarrier demodulation followed by an inverse transformation step takes the received signal back to the delay-Doppler domain. The authors in [4] deployed an inverse symplectic finite Fourier transform (SFFT-1) operation to translate data symbols from the delay-Doppler to the time-frequency domain, at the transmitter. Consequently, a symplectic finite Fourier transform (SFFT) operation, i.e. the re