Low-Complexity Channel Estimation in OTFS Systems with Fractional Effects

Abstract: Orthogonal Time Frequency Space (OTFS) modulation exploits the sparsity of Delay-Doppler domain channels, making it highly effective in high-mobility scenarios. Its accurate channel estimation supports integrated sensing and communication (ISAC) systems. The letter introduces a low-complexity technique for estimating delay and Doppler shifts under fractional effects, while addressing inter-path interference. The method employs a sequential estimation process combined with interference elimination based on energy leakage, ensuring accurate channel estimation. Furthermore, the estimated channel parameters can signifcantly improve ISAC system performance by enhancing sensing capabilities. Experimental results validate the effectiveness of this approach in achieving accurate channel estimation and facilitating sensing tasks for ISAC systems.