Low Complexity MMSE-SIC Receiver for OTFS in High-Speed Mobile Scenarios

Orthogonal Time Frequency Space (OTFS) has attracted the attention of researchers due to its excellent BER performance in high-speed mobile scenarios. In this letter, a low complexity Minimum Mean Square Error Serial Interference Cancellation (MMSE-SIC) receiver is proposed, which replaces the computationally intensive matrix inversion calculations in the symbol decision process with two low complexity algorithms. Firstly, a low complexity LDLH decomposition algorithm is proposed based on the properties of the equivalent channel matrix. Secondly, a low complexity algorithm is put forward for the inversion of lower triangular matrices. Finally, the concept of adjustable parameter is introduced to achieve dynamic adjustment of complexity. Simulation results demonstrate that the proposed algorithm achieves significant performance gains compared to the linear equalization algorithm and similar BER performance as the traditional SIC algorithm with reduced complexity.