Demonstrating a Low-Cost and Zero-Recurrent-Cost Hybrid Mesh & Satellite Based Early Warning System

Decentralized mesh and peer-to-peer networks can be a highly effective way to allow local communications within an isolated community, through lack of reliance on fixed infrastructure. This independence from the outside world is a two-edged sword: it is one of the main reasons for their resilient operation, but it also creates a problem when information from the outside world is required. This makes it difficult to use to deliver early warning for pending disasters or other adverse events, because there is no path between the isolated communications zone and the outside world. In this paper we show how this situation can be resolved by applying recent advances in satellite broadcasting, where very small antenna, as small as 6 cm diameter, that do not require accurate aiming can be used to receive a broadcast satellite signal. Further, these receivers can be produced for less than US$100, and consume less than 2W, making them feasible for deployment in resource constrained and other difficult circumstances. These innovations make it possible to have a small device that can be self-deployed by communities and that is able to receive data via satellite, thus providing a one-way bridge to the outside world. More specifically, we demonstrate the feasibility of creating exactly an example of this through the integration of the Serval Mesh peer-to-peer communications system together with a low-cost Ku-band satellite receiver from Outernet. We demonstrate the ability to deliver information into isolated areas using this system, including the ability to provide early warning notices with latency of less than 1 minute, i.e., fast enough to provide early warning for Tsunami and other rapid-onset events. Crucially, we show how such a service can be delivered without incurring recurrent per-subscriber charges, which are impractical for impoverished and remote communities. We also describe future work to: (1) reduce the latency to as low as 5-10 seconds, so that more challenging applications such as earthquake early warning become possible; and (2) implement two-way communications using the same sub-$100 terminal hardware, based on advances that Outernet have made in low-power narrow-band spread-spectrum earth-to-space communications.