Equalizing Energy Distribution in Sensor Nodes through Optimization of RPL

We present a nodes´ remaining energy-aware objective function in order to equalize the energy distribution among the nodes with the ultimate goal of extending the lifetime of the network. Routing Protocol for Low Power and Lossy Networks (RPL) is the routing standard for the Internet of Things. It chooses the optimal routes from a source to a destination node based on specific metrics. Since the nodes in such networks have limited energy resource, the dying of a node may result in the loss of part of the network or the entire network depending on the topology. The designed objective function uses both expected transmission count (ETX) and remaining energy of parent nodes to determine the preferred parent. Simulations are carried out using Contiki OS and its Cooja emulator. The simulation results reveal that the proposed objective function increases the lifetime of the first node to die in the network compared to Minimum Rank with Hysteresis Objective Function (MRHOF). It is also observed that the nodes´ energy depletion rate in the network, which uses the proposed nodes´ energy-aware objective function, is closer to each other than the one using MRHOF.