Angular-Domain Signal Processing Methods in MIMO-OTFS System

Orthogonal time frequency space (OTFS) technology exhibits superior performance in high mobility environments. While integrating OTFS with Multiple-Input Multiple-Output (MIMO) technology can enhance spectral efficiency, significant challenges arise due to the complexity of channel conditions. In this paper, we propose signal processing methods for MIMO-OTFS according to different channel conditions. First, we analyze the input-output relationship of the single-input single-output (SISO) OTFS and extend it to MIMO-OTFS in the delay-Doppler-angle (DDA) domain. We formulate the signal relationships under three channel scenarios: ideal channel, channel dispersion and channel overlapping. Based on that, we propose the corresponding signal processing algorithms. Simulation results show that the proposed algorithms can improve system performance.