Stable and Delay Efficient Routing Objective Function for Mobile IoT Networks

Routing Protocol for Low Power and Lossy Networks (RPL) is the default routing standard used in many Internet of Things (IoT) deployments. It is specifically tailored for environments where devices operate with strict limitations on memory, computation capability, energy, and communication rate. RPL typically relies on two standardized objective functions - OF0 and MRHOF - to determine efficient routing paths. However, these mechanisms struggle in scenarios involving node mobility. Ensuring stable and efficient routes becomes a major challenge when the network includes mobile IoT devices. Hence, in this paper, a Stable and Delay Efficient Objective Function (SDOF) is proposed to optimise stability and efficiency by assuming node density, node mobility, and expected data delay (EDD) for routing decisions. SDOF improves the average end-to-end delay of the network by 57% compared to OF0 and the stability of the network by 30% compared to MRHOF. In addition, SDOF shows improved performance with respect to packet delivery, throughput, and control packet overhead compared to the existing benchmark schemes.