Experimental Test-Bed Implementation of Hybrid Opportunistic Routing Design for Low Power, Lossy Wireless Sensor Network

Abstract

The past decade has witnessed numerous Routing design proposals for wireless multi-hop network specifically for Wireless Sensor Network (WSN) and recently its allied Low Power, Lossy Networks (LLN) in the era of Internet of Things (IoT). However, experimentation using sensor motes in real test-bed is limited as majority cater to simulation analysis. This work proposes and implements a Hybrid Opportunistic Routing (OR) design for Low Power, Lossy WSN. The routing protocol adopts opportunistic mode of forwarding as the first and last resort to improve end-to-end packet delivery ratio. The protocol switches to unicast mode for successive transmissions by relying on trust-worthy forwarder(s) until link-level transmission error occurs. The OR phases such as candidate selection, prioritization and coordination are carried out on the fly in a completely distributed online manner by eligible forwarders. These forwarder(s) computes its priority order based on cross-layered routing metrics in a fuzzy manner and collaborate via timer coordination with differentiated Back-off Exponent (BE) parameters assignment for packet forwarding. The real test-bed experimentation using IEEE 802.15.4 compliant SENSEnuts platform recorded the lossy-link characteristics during range test measurements. The proposed hybrid OR showed improvement in end-to-end delivery rate with increase in hops and number of forwarding candidates per level compared to level based unicast routing.