Scheduling Models for Industrial Internet of Things Networks

IEEE 802.15.4-2015 Time Slotted Channel Hopping (TSCH) Networks have gained a lot of attention within the Industrial Internet of Things (IIoT) research community due to its effectiveness in improving reliability and providing ultra-low power consumption for industrial applications, where communication is orchestrated by a schedule. The key feature of TSCH is the scheduling of time slots and frequencies, which can be typically created in various ways but should be computed according to specific requirements, such as throughput, energy, reliability and latency. Despite the promising features of the TSCH, IEEE 802.15.4 standard leaves out of its scope in defining how the schedule is built and maintained, which is the focus of this research. This thesis presents a centralized scheduling model in IEEE 802.15.4-2015 TSCH Networks, where the gateway makes frequency allocations and time slot assignments. We propose different scheduling models focusing on maximizing the overall throughput, minimizing the average scheduling delay, maximizing the energy efficiency, and providing throughput fairness through max-min fair approach. In achieving these, we devise algorithm-based optimal, sub-optimal yet heuristic algorithms. In addition to the heuristic algorithms and simulation-based studies, this thesis also provides a graph theoretical approach and proposes polynomial time graph algorithms. Moreover, experimental measurements are conducted on different platforms and various operating systems to assess the energy consumption and evaluate the impact of TSCH protocol. Lastly, the thesis focuses on emerging technologies for the Internet of Things (IoT), where we present a simple and general Software Defined Networking (SDN)-IoT architecture with Network Function Virtualization (NFV) implementation, providing specific choices on where and how to adopt SDN and NFV approaches to address the new challenges of the IoT.