Efficient Demodulation Algorithms for MIMO-LoRa

Multiple-input-multiple-output (MIMO) and long range (LoRa) have been synergistically combined to better support a variety of Internet of Things (IoT) applications. This letter investigates the problem of demodulation for a MIMO-LoRa system. The existing demodulation strategy for MIMO-LoRa is based on the maximum-likelihood criterion, which, however, suffers from its high computational complexity. To cope with this issue, in this letter, we develop efficient coherent and noncoherent demodulation algorithms for the MIMO-LoRa system by leveraging useful properties of modulated chirps through multiple antennas. We also analyze the computational complexities of the proposed algorithms and demonstrate their validity through numerical simulations.