Receiver Design for OTFS with a Fractionally Spaced Sampling Approach

The recent emergence of orthogonal time frequency space (OTFS) modulation as a novel PHY-layer mechanism is more suitable in high-mobility wireless communication scenarios than traditional division multiplexing (OFDM). Although multiple studies have analyzed OTFS performance using theoretical and ideal baseband pulseshapes, challenging open problem the development effective receivers for practical systems that must rely on non-ideal pulseshapes transmission. This work focuses design OTFS. We consider fractionally spaced sampling (FSS) receiver which rate an integer symbol rate. For rectangular pulses used transmission, we derive general channel input-output relationship delay-Doppler domain without common reliance impractical assumptions such bi-orthogonal on-the-grid delay/Doppler shifts. propose two equalization algorithms: iterative combining message passing (ICMP) turbo (TMP) detection by exploiting sparsity diversity gain via FSS. analyze convergence TMP simplified (MP) to further reduce complexity. Our FSS demonstrate stronger robustness imperfect state information knowledge.