OF-EC: A novel energy consumption aware objective function for RPL based on fuzzy logic.

Low-Power and Lossy Networks (LLNs) have recently emerged as a promising and attractive paradigm. The IPv6 Routing Protocol for Low Power and Lossy Networks (RPL), proposed by the IETF ROLL working group, is specifically designed for LLN and is compliant with the 6LoWPAN protocol. RPL has gained a significant maturity, and is still attracting more researchers contributing to its improvement. RPL builds a Destination Oriented Directed Acyclic Graph (DODAG) based on a set of metrics and constraints through specific Objective Functions (OFs). The OFs select the best parent of nodes to build and optimize the route. However, the standard objective functions have some limitations due to the use of a single metric. In this paper, we propose a new OF based on combined metrics using Fuzzy Logic (OF-EC). To overcome the limitations of the use of a single metric, the proposed OF-EC considers both the link and the node metrics, namely the Expected Transmission Count (ETX), Hop Count (HC) and the Energy Consumption (EC). The simulation results demonstrate the effectiveness of the new OF-EC in comparison with the MRHOF, ENTOT, and OF-FUZZY in improving RPL performances in terms of PDR, network lifetime, convergence time, latency, overhead, and energy consumption. Our results show that OF-EC keeps the RPL overall efficiency independent from the network topology and the transmission range. Moreover, the proposed OF-EC outperforms the other proposals in balancing the energy consumption of all nodes in the network.