A&M Based fractional delay and Doppler Channel Estimation in OTFS

Orthogonal Time Frequency Space (OTFS) modulation is a promising technique for mitigating Doppler effects in high-mobility environments, making it suitable for Low-Density High-Mobility Communication (LDHMC) in 6G. However, accurate channel estimation, especially of fractional delay and Doppler, remains a major challenge. This paper introduces a low-complexity channel estimation method based on the A&M frequency estimation algorithm, capable of precisely recovering delay, Doppler, and channel gain. We provide mathematical justification for the need to estimate exact delay and Doppler values, highlighting the limitations of conventional virtual tap-based methods in reliable information detection. The proposed approach is validated through MATLAB simulations under both Line-of-Sight (LoS) and Non-Line-of-Sight (NLoS) conditions across various frame sizes. Results show that our method significantly outperforms traditional embedded estimation techniques, offering improved accuracy and robustness in realistic 6G scenarios.