Mobility Aware Framework for Timeslotted Channel Hopping IEEE 802.15.4e Sensor Networks

Ubiquitous object networking has sparked the concept of the Internet of Things (IoT), which defines a new era in the world of networking. Realization of this concept needs to be addressed by standardization efforts that will shape the infrastructure of the networks. This has been achieved through the IEEE 802.15.4e, 6LoWPAN, and IPv6 standards. In addition, the IEEE 802.15.4e standard, which can be considered as the backbone of the IoT structure, has presented timeslotted channel hopping (TSCH). Although these standards provide a coherent and diffused system, several implications challenge these standards to achieve optimal performance and reliability. Node mobility can be considered as the delimited factor for realizing a fully connected network, especially with the inclusion of TSCH mode that will complicate the association process of the mobile nodes, as a result of the frequency hopping mechanism. In this paper, we investigate the impact of mobility over the TSCH sensor network, and a Markov chain model is presented to determine the parameters that affect mobile node association process. Second, we provide a proposed mobility-aware Mobile Timeslotted Channel Hopping (MTSCH) protocol that will facilitate the mobile nodes association and minimize the latency incurred by leaving the nodes dissociated from the network. TSCH and the proposed MTSCH techniques have been implemented and evaluated through Contiki OS. The proposed MTSCH manages to reduce the radio duty cycle of the mobile nodes by an average of 30% while increasing the connectivity of the nodes by 25%. Moreover, cluster heads managed to save energy by a ratio of 14%.