Low-Complexity Sparse Compensation MRC Detection Algorithm for OTSM Systems

Orthogonal time sequency multiplexing (OTSM) has recently attracted significant attention due to its enhanced robustness in doubly selective fading channels. However, the computational complexity of conventional OTSM receivers increases significantly in scenarios with fractional Doppler shifts. In this work, we first analyze the effects of inter-Doppler interference on the performance of OTSM systems. We then propose a sparse compensation maximum ratio combining (SC-MRC) detection algorithm to mitigate computational complexity. Specifically, a channel sparsification procedure is implemented by eliminating amplitude values that fall below a predetermined threshold, thereby substantially reducing the computational complexity associated with matrix multiplication. A low-complexity adaptive compensation scheme is introduced to mitigate the associated performance degradation. Simulation results demonstrate that the proposed SC-MRC algorithm achieves superior performance compared to the conventional MRC algorithm while offering reduced computational complexity.