A novel opportunistic Fuzzy logic based objective function for the Routing Protocol for Low-Power and Lossy Networks

Low power and lossy networks (LLNs) are constrained networks that need specific routing protocols able to meet application requirements such as latency and reliability. RPL was designed by the IETF ROLL working group for such challenging networks. It defines an objective function (OF) that can operate according to a set of metrics and constraints to make nodes select best parents and then construct paths. Considering the vast areas of applications for RPL, used metrics and constraints combinations was left an open issue for implementation. In this paper, we propose an opportunistic fuzzy logic based OF (OPP-FL) that takes into consideration a novel routing metric measuring neighbor load in addition to traditional IETF ROLL specified metrics. Our proposed scheme combine through a fuzzy logic process the traditional expected transmission count (ETX) and Hop Count (HC) metrics to proposed Children Number (CN) metric. Simulation results reveal that compared to the based ETX OF, namely MRHOF and the OF-EC a fuzzy logic based OF has achieved better performances in terms of PDR and acceptable results in terms of delay when the network size expands without inducing high traffic overhead.