Multi-hop Device-to-Device Routing Protocols for Software-Defined Wireless Networks

University of Technology Sydney. Faculty of Engineering and Information Technology.Multi-hop device-to-device (MD2D) communications are an integral part of future wireless networks. Multi-hop communications enable mobile devices in close proximity to communicate directly or through multi-hop connections instead of traversing through a network infrastructure. This provides numerous benefits for cellular networks, such as low-cost communications, enhanced cellular coverage and capacity, reduced total power consumption in devices, and improved spectral efficiency. Consequently, service providers can leverage the advantages of both D2D and cellular networks to enhance the quality of their services. However, tight coupling of control and data functions in cellular equipment and the utilization of proprietary interfaces and protocols in existing cellular infrastructure make integration difficult and rigid. Hence, there is a need for open and reprogrammable frameworks to make the network more flexible and scalable. Software-defined networking (SDN) is a promising technology for future wireless networks that provides an open and reprogrammable framework wherein the control functions are taken from network devices and are logically centralized in a control entity. The open framework of SDN provides an opportunity for service providers to manage networks more intelligently and develop services in a more agile manner. This thesis introduces an SDN-based framework for cellular networks, referred to as virtual ad hoc routing protocol framework (VARP), capable of developing different types of multi-hop routing protocols. In the proposed framework, an SDN controller determines the mode of communication for mobile devices (i.e., cellular or multi-hop modes). Two different multi-hop routing protocols are designed for the proposed framework: source-based virtual ad hoc routing protocol (VARP-S) and SDN-based multi-hop D2D routing protocol (SMDRP). In both protocols, a source of data packet sends a route request to the controller and receives the forwarding information from the controller in response. This thesis then presents a multi-protocol framework capable of developing multiple routing protocols under a single framework. In the proposed framework, an SDN controller logically divides a cell into multiple clusters based on its knowledge of the entire cell. The controller determines which multi-hop routing protocol can provide the best performance for each cluster. The simulation results show that the proposed multi-protocol framework provides better performance than traditional single-protocol architectures. Finally, the thesis presents a novel software-defined adaptive routing algorithm for multi-hop multi-frequency communications in wireless multi-hop mesh networks. The simulation results indicate that the proposed algorithm improves the end-to-end throughput of multi-hop connections by considering the surrounding WiFi traffic and adaptive selection of frequencies and routes

A Multi-Criteria Framework to Assist on the Design of Internet-of-Things Systems

The Internet-of-Things (IoT), considered as Internet first real evolution, has become immensely important to society due to revolutionary business models with the potential to radically improve Human life. Manufacturers are engaged in developing embedded systems (IoT Systems) for different purposes to address this new variety of application domains and services. With the capability to agilely respond to a very dynamic market offer of IoT Systems, the design phase of IoT ecosystems can be enhanced. However, select the more suitable IoT System for a certain task is currently based on stakeholder’s knowledge, normally from lived experience or intuition, although it does not mean that a proper decision is being made. Furthermore, the lack of methods to formally describe IoT Systems characteristics, capable of being automatically used by methods is also an issue, reinforced by the growth of available information directly connected to Internet spread. Contributing to improve IoT Ecosystems design phase, this PhD work proposes a framework capable of fully characterise an IoT System and assist stakeholder’s on the decision of which is the proper IoT System for a specific task. This enables decision-makers to perform a better reasoning and more aware analysis of diverse and very often contradicting criteria. It is also intended to provide methods to integrate energy consumptionsimulation tools and address interoperability with standards, methods or systems within the IoT scope. This is addressed using a model-driven based framework supporting a high openness level to use different software languages and decision methods, but also for interoperability with other systems, tools and methods