Routing Protocol for Reliable Mobile Communication Using Wi-SUN FAN

The wireless smart ubiquitous network (Wi-SUN) field area network (FAN), an emerging wireless multihop communication standard for Internet of Things systems, is used to develop smart cities, metering, and factory infrastructure. The Wi-SUN FAN adopts the Internet Protocol version 6 routing protocol for low-power and lossy networks and employs the exponentially weighted moving average method, which considers historical values of link metrics to configure robust multihop networks. Because the deployment of mobile nodes is an indispensable aspect of the development of smart cities and smart factory infrastructure, the Wi-SUN FAN should be able to route mobile nodes. To this end, this study employ computer simulations and field experiments to evaluate the packet delivery ratio (PDR) of a mobile Wi-SUN FAN node operating under a conventional routing protocol, thereby revealing the causes of PDR degradation. To overcome these limitations, we propose a routing protocol that considers the moving direction of the mobile node to ensure reliable mobile communication within the Wi-SUN FAN. Computer simulations show that the PDR improves by up to 87% (PDR points range from 0.125 to 0.995) under the proposed protocol compared to conventional routing protocols when the node moves at 10 m/s. In experiments using actual equipment, the PDR improves by up to 38% (PDR points range from 0.476 to 0.859) when the node moves at 0.26 m/s. The simulation and experimental results confirm that the proposed routing protocol overcomes the limitations of the conventional routing protocol through swift parent handover and selection, regardless of the direction of movement.