Towards a video-capable wireless underwater modem: Doppler tolerant broadband acoustic communication

Current wireless underwater modems are advertised with data rates of only a few kbps and the oil and gas industry has found them incapable of handling video and real-time control. Today, such communication underwater is almost entirely done through wired links. Using broadband acoustic signals with a bandwidth of 200kHz and more, we demonstrate the feasibility of wireless underwater communication at data rates greater than 1Mbps. Such data rates are capable of streaming video in real-time. As broadband acoustic signals propagate through water, they suffer extreme Doppler effects. Different propagation paths experience different Doppler and the level of Doppler on each path is highly time-variant. In our work, time-varying Doppler is explicitly modeled, tracked and compensated. In this paper, we provide the results from our acoustic communication experiments conducted in a 50m long wave tank. Our resampling equalizer reliably achieved 1.2Mbps over a distance of 12m.