High-mobility wireless communication systems are significantly affected by Doppler spread and multipath delay. Orthogonal Time Frequency Space (OTFS) modulation is a robust solution to handle such impairments by mapping information symbols to the delay-Doppler (DD) domain, where the channel exhibits inherent sparsity. In this context, accurate channel state information at the transmitter (CSIT) is essential for fully exploiting the potential of multiple-input multiple-output (MIMO) systems. In this work, we propose a novel, low-overhead channel state information (CSI) feedback mechanism tailored to MIMO-OTFS systems that leverages the sparsity of the DD channel representation. The proposed method performs path-wise quantization of dominant channel coefficients and incremental refinement of CSI using binary-structured feedback, enabling adaptive precision and progressive updates. Unlike conventional one-shot scalar quantization or codebook-based approaches, our method reduces feedback load while maintaining fidelity even under high-mobility scenarios. We derive tractable closed-form lower bound expressions for ergodic and outage achievable rates under inaccurate CSI, explicitly accounting for channel estimation and quantization errors. Rate-distortion bounds are used to quantify the trade-off between the number of feedback bits and achievable rate. Simulation results confirm the utility of our approach in terms of spectral efficiency, robustness to feedback imperfections, and scalability to large MIMO settings.
Kolla et al. (Thu,) studied this question.