Spatially Correlated MIMO-OTFS for LEO Satellite Communication Systems

Low earth orbit (LEO) satellite communication (satcom) systems are expected to provide reliable high-speed communications under high-mobility environments. Recent research has demonstrated that the orthogonal time frequency space (OTFS) modulation technique has the potential to meet the demands for LEO satcom. In addition, multiple-input multiple-output (MIMO) communication technology has been deployed in LEO satcom systems. This paper investigates the performance of MIMO-OTFS based LEO satcom systems, considering spatial correlation at both the transmit and receive ends. As the error performance degrades due to the correlation effect, this work proposes whitening transformations at the transmitter (Tx) and the receiver (Rx) to combat the Tx/Rx spatial correlations. Simulation results with practical LEO satcom channel models and configurations demonstrate a significant improvement in the error performance with the proposed decorrelation operations.