Low-Complexity Linear MIMO-OTFS Receivers

Orthogonal time-frequency space (OTFS) scheme, which transforms a time and frequency selective channel into an almost non-selective delay-Doppler domain channel, establishes reliable wireless communication links for high-speed moving devices. This work designs and analyzes low-complexity zero-forcing and minimum mean square error receivers for multiple-input multiple-output (MIMO)-OTFS systems for both perfect and imperfect channel state informations. The proposed receivers provide exactly the same solution as that of their conventional counterparts, and reduce the complexity by exploiting the doubly-circulant nature of the MIMO-OTFS channel matrix, the block-wise inverse, and Schur complement. We numerically show the same bit error rate and lower complexity of the proposed designs over the conventional ones.