D2D-enabled Failure-tolerance in Cellular IoT

Failure-tolerance is an essential feature of any reliable system. In the context of Cellular IoT, mechanisms preventing the communications collapse at the event of failure are desired, if critical applications are to be deployed. In particular, this paper addresses the scenario, in which the end-devices, located in a remote and hard-to-reach area, experience a failure of the only base station in proximity. We propose a reliable and lightweight scheme that sustains the connectivity by means of a Device-to-Device link, established with a foreign device acting as a relay. Since the direct communications occurs only at the time of the failure, the solution introduces minimised overhead towards the relay device, which in our proposal can be realised by constrained hardware. We explain the assumptions, the behaviour and signalling patterns of the system. Finally, we discuss the applicability of our scheme and provide implementation considerations.