An innovative RPL objective function for broad range of IoT domains utilizing fuzzy logic and multiple metrics

Abstract

The indispensable part of IoT is the Low-power and Lossy Network (LLN), which is required to connect plenty of resource-constrained (e.g., power and memory) wireless devices. Interestingly, the IPv6 Routing Protocol for LLNs (i.e., RPL), which is the standard routing protocol for IoT, relies primarily on constructing a destination-oriented directed acyclic graph governed by a variety of routing metrics that help in choosing the Objective Function (OF), which is liable for selecting the best preferred parent of each node which in turn gets involved in the route establishment towards the destination. In fact, establishing an OF based on a single metric, as the majority of research considers, has flaws or drawbacks, as it only benefits a few IoT applications. To put it another way, the network lifetime is improved for a few IoT apps but degraded for the majority. In this article, we address not only the limitation of using a single metric, but also the limitations of those works employed a composite metric by putting forward a cross-layer design and accordingly developing a fuzzy logic system that brings together four input metrics, namely, hop count, energy consumption, latency, and received signal strength indicator as a new OF, abbreviated as FL-HELR-OF. The simulation findings, acquired by the Cooja simulator, prove the effectiveness of our new OF, which particularly outperforms other existing studies concerning the packet delivery ratio, control message overhead, latency, energy consumption, and average hop count.