Low-Complexity Iterative Equalization for OTFS Based on Alternating Minimization

To achieve robust communication in high mobility scenarios, an iterative equalization algorithm based on alternating minimization (AM) is proposed for the orthogonal time frequency space (OTFS) system. The algorithm approximates the equalization problem to a convex function optimization problem in the real-valued domain and solves the problem iteratively using the AM algorithm. In the iterative process, the complexity of the proposed algorithm is reduced further based on the study of the cyclic structure and sparse property of the OTFS channel matrix in the delay-Doppler (DD) domain. The new method for OTFS is simulated and verified in a high-speed mobile scenario and the results show that the proposed equalization algorithm has excellent bit error rate performance with low complexity.