Taking LoRa for a Dive: CSS for Low-Power Acoustic Underwater Communication

Long Range (LoRa) is a rising technology for low-power over-water wide area networks. In this paper, we modify the physical layer (PHY) of the LoRa communication standard for use in acoustic underwater communication. First, we describe a light-weight LoRa-inspired chirp spread spectrum (CSS) implementation and evaluate it in simulations and realworld trials. Second, we compare our results to the JANUS underwater communication standard. Especially in scenarios with strong multipath propagation, our CSS implementation offers advantages compared to JANUS communication. Third, we pinpoint weaknesses and identify room for improvements.