Low Complexity Channel Estimation Based on UAMP for Orthogonal Time Frequency Space Systems

To address the problem of high complexity of channel estimation for orthogonal time frequency space (OTFS) systems, we propose a low complexity channel estimation method leveraging the unitary approximate message passing (UAMP) algorithm. Specifically, the estimation of OTFS channel is represented as a linear mixing model, which is handled using UAMP, avoiding the matrix inversion operations in the state-of-the-art algorithm. Numerical results demonstrate that, with significantly lower complexity, the proposed algorithm can achieve almost the same channel estimation performance, compared to the benchmark algorithm.