Next-generation waveform design: Experimental ZAK-OTFS evaluation across FR1, FR2, and FR3 for mobility and doppler robustness

Orthogonal Time Frequency Space (OTFS) modulation has emerged as a robust waveform for high-mobility and doubly dispersive channels, outperforming OFDM under strong Doppler. However, the most studied multicarrier OTFS (MC-OTFS) is not easily predictable because the input-output (I/O) relation is not given by (twisted) convolution. Recently, the Zak transform based OTFS (Zak-OTFS or OTFS 2.0) was proposed, which provides a single-domain delay–Doppler (DD) processing framework with predictable I/O behavior. This paper presents one of the first over-the-air (OTA) demonstrations of Zak-OTFS at FR1, FR2, and FR3 frequencies as well as one of the first OTA demonstrations introducing Zak-OTFS to pedestrian and vehicular mobility conditions. We design a complete Zak-OTFS-based OTA system featuring Sinc, root-raised-cosine (RRC), Gaussian, and Gaussian-Sinc (Ginc) filtering for enhanced DD-domain predictability, higher-order modulations up to 16-QAM, and a low-overhead preamble for synchronization. A comprehensive signal model incorporating carrier frequency offset (CFO) and timing impairments is developed, showing these effects can be jointly captured within the effective DD-domain channel. Experimental validation on the COSMOS testbed confirms the feasibility and robustness of Zak-OTFS under realistic FR1, FR2, and FR3 conditions, and vehicular mobility conditions highlighting its potential for efficient implementations in beyond-5G and 6G systems.