MIMO-OTFS Transceiver Design Based on Stream-Level SINR

This paper investigates a wideband linear transceiver architecture for multiple-input multiple-output orthogonal time frequency space (MIMO-OTFS) system. By examining the input-output relationship in the delay-Doppler-beam (DDB) domain, the stream-level signal-to-interference-plus-noise ratio (SINR) is validated to be approximately equivalent to the OTFS symbol-level SINR under ideal delay-Doppler (DD) domain equalization. This gives rise to a novel framework for designing MIMO-OTFS transceivers by formulating the optimization problem based on the stream-level SINR, which is more mathematically tractable, instead of the symbol-level SINR. Particularly, a MIMO-OTFS transceiver employing zero-forcing (ZF) as well as maximum ratio transmission (MRT) and maximum ratio combining (MRC) is simulated to evaluate the system's average achievable rate under the given channel conditions, thereby validating our conclusions.