IRH-OF: A New Objective Function for RPL Routing Protocol in IoT Applications

Faced to challenges of low power and lossy networks (LLN’s) as well as the nature of these networks without infrastructure, it remains the subject of several researches to deal with routing constraints and thus propose adapted routing protocols according to different applications. In this context, a protocol based on Ipv6 RPL has been standardized to meet the requirements of low power and lossy networks. RPL centralizes traffic to one or more nodes through the construction of a Destination Oriented Directed Acyclic Graph (DODAG) based on a specific objective function. Nevertheless, the objective function influences the behavior of the routing protocol, so that the design must follow the prerequisites of each application. The problem of standardized objective functions is found in their routing paths selection, they are not based on different criteria which leads to unoptimized choices of routes which affects the network quality of services . Thus, we propose in this paper a new objective function IRH-OF based on designed combined metric cmIRH for rank calculation. Our proposed method, injected on the core of Contiki Operating System, ensures a better quality of services compared to other objective functions. The results showed that the new objective function can maintain a packet delivery ratio higher than 98% regardless of density, decreases approximately with 45% the average power consumption of the network, achieves a less convergence time and latency.