Doppler Rate Estimation for OTFS based Communication Systems in High Mobility

Orthogonal Time Frequency Space (OTFS) modulation has emerged as a promising solution for reliable communication in high-mobility environments due to its robustness in rapidly varying channels. In this study, we address the challenge of estimating the Doppler rate, which refers to the time variation of the Doppler shift caused by accelerating or decelerating motion. We use a subspace-based estimation framework that exploits the structural properties of OTFS signals in the delay-Doppler domain. By analyzing the evolution of signal components over time, the system can accurately track Doppler rate variations. Simulation results validate the effectiveness of the proposed approach, showing improved performance in scenarios such as high-speed trains and vehicular networks. High mobility scenarios, such as those encountered in high-speed trains and autonomous vehicles, demand communication systems that can adapt to fast changing signal conditions. OTFS modulation provides a resilient structure for handling such environments. This paper presents a method to estimate the Doppler rate — a key parameter that captures how the Doppler shift evolves due to motion changes. The proposed technique leverages subspace analysis within the OTFS framework to track these variations effectively. Results from simulations indicate strong potential for real time deployment in mobility-sensitive applications, enhancing the reliability of wireless links in future networks.