Iterative Channel Estimation/Detection for DZT-OTFS Using Superimposed Pilot Frames

Motivated by its inherent robustness to Doppler spread, Zak transform-based orthogonal time-frequency space (OTFS) modulation has emerged as a promising candidate for next-generation wireless technologies, particularly in the 6G and beyond framework. In this paper, we introduce a novel channel estimation algorithm for discrete Zak transform (DZT)-based OTFS, employing a superimposed pilot frame structure and capable of accommodating arbitrary pulse shapes and fractional delay-Dopplers (DD). The proposed algorithm leverages the DD channel invariance across multiple OTFS frames, which offers the benefit of multiple measurements in channel estimation. Extensive simulation results demonstrate that the proposed algorithm achieves good bit error rate (BER) and normalized mean square error (NMSE) performance, showcasing its effectiveness in practical communication settings. Impact of the use of different detectors on the iterative channel estimation/ detection performance is also studied.