Low Complexity Channel Estimation in OTFS Enabled MIMO Systems

In this paper, a multiple input multiple output (MIMO) orthogonal time frequency space (OTFS) signal enabled system is considered, in which the receiver leverages embedded pilot (EP) for channel estimation. Practically, the Doppler shifts associated with the wireless channel may fall out of the integer multiple assumption and the traditional low complexity threshold-aided embedded pilot channel estimation (CE) scheme will deliver less accuracy in the estimates. Hence, we propose a low complexity algorithm for the evaluation of fractional Doppler shifts along with the delays and gains in the channel. The low complexity estimation of fractional Doppler shift is facilitated by the utilization of Candan’s formula. Simulation results are presented to validate the performance of the proposed method.