Performance Analysis for Orthogonal Time Frequency Space Modulation Systems with Generalized Waveform

Orthogonal time-frequency space (OTFS), which exhibits beneficial advantages in high-mobility scenarios, has been considered as a promising tech-nology in future wireless communication systems. In this paper, a universal model for OTFS systems with generalized waveform has been developed. Further-more, the average bit error probability (ABEP) upper bounds of the optimal maximum likelihood (ML) de-tector are first derived for OTFS systems with general-ized waveforms. Specifically, for OTFS systems with the ideal waveform, we elicit the ABEP bound by re-combining the transmitted signal and the received sig-nal. For OTFS systems with practical waveforms, a universal ABEP upper bound expression is derived us-ing moment-generating function (MGF), which is fur-ther extended to MIMO-OTFS systems. Numerical re-sults validate that our theoretical ABEP upper bounds are concur with the simulation performance achieved by ML detectors.