Practical Implementation of Zak-OTFS and Its Relation With OFDM

The rapid evolution of wireless communication technologies imposes stringent requirements on modulation schemes, particularly in doubly-dispersive channels caused by high mobility and high-frequency operation. While Orthogonal Frequency-Division Multiplexing (OFDM) struggles in such scenarios, Orthogonal Time Frequency Space (OTFS) modulation has emerged as a promising alternative by leveraging the delay-Doppler domain for enhanced robustness. However, conventional implementations such as multicarrier OTFS (MC-OTFS) suffer from an intrinsic drawback, i.e., the complicated input-output relation. To address these limitations, a refined OTFS framework—Zak-OTFS has been proposed. This paper reviews the signal model of Zak-OTFS, establishing its structural and mathematical connection to OFDM under a specific windowing operation, and explores its advantages in terms of implementation and performance. To be specific, based on an embedded pilot scheme, we analyze the impact of time-frequency window functions with different sidelobe behaviors on communication reliability. The results highlight the critical role of windowing in channel estimation and communication performance.