Mobility management for software defined wireless sensor networks

Abstract: By advancing technologies in both hardware and software, it is possible to support more complex applications. Wireless Sensor Networks (WSNs) comprised of tiny sensing devices with wireless radios are the key enablers for future Internet of Things(IoT) applications, where collecting measurements and delivering them to their destination is the most important task. In traditional sensor networks, sensor nodes were typically stationary and each node periodically measured and sent data to the next predefined router. However, in current applications, some nodes are expected to move. For instance, in health monitoring applications, where patients with sensors attached to their body are free to move in the hospital or their houses. Software Defined Networking (SDN) is a technique that was conventionally used in wired networks, and recently was used in some wireless networks, such as cellular and wireless local area networks. The idea of SDN is to provide more flexibility in the network by getting the advantage of re-programmability of the network devices during run-time. In networks based on SDN, the control plane is shifted from the infrastructure to a higher level in order to provide re-configuration. The controller decides on updating forwarding rules by getting some feedback from nodes in the network. In wireless sensor networks, the feedback may contain information related to the link quality and available resources such as battery level and the location of the sensor node (number of hops away from the sink). In this thesis, a study ofseveral relevant SDN-based architectures for wireless sensor networks is given, outlining the main advantages and disadvantages for each. In addition, some mobility solutions in sensor networks such as localization, routing and hand-off algorithms are explored. One of the drawbacks with SDN is that it was originally built for wired networks there experience with mobility does not exist. Thus the thesis considers the possibility to use SDN solutions in WSN were certain applications are in need of mobility. Finally, the thesis propose mobility solution for sensor networks that takes advantage of SDN and uses a handoff algorithm. In fact, the hand-off mechanism is achieved by means of control message exchanges that is supervised by the controller.