Resource management and IP interoperability for low power wide area networks
Hassan, Khaled Q. Abdelfadeel
University College Cork
Low Power Wide Area Networks (LPWANs) such as LoRaWAN, Sigfox, and NBIoT present a novel communication paradigm, which complements the traditional short-range Wireless Sensor Networks (WSNs). LPWANs promise to provide wide-area connectivity (up to tens of kilometers) and low-power operations (up to 10years) for a massive number of low-cost devices. These unique features empower LPWANs to address diverse requirements of the Internet of Things (IoT) applications, from agriculture to smart cities. Since the early days of LPWANs, a major hype has surrounded them, making it sometimes difficult to clearly understand and assess their capabilities. This has been inflated with biased reports and inaccurate data to promote even inapplicable solutions. Therefore, the thesis’s goal has been set to assess the network stack of the LPWAN technologies, especially LoRaWAN, in different scenarios in order to understand their real advantages for the IoT applications and also to point out their drawbacks. Consequently, proposing improvements in order to enhance the performance and to extend the application domains of the LPWANs, taking into account their limitations, e.g., duty cycle. Specifically, resource management and IP interoperability topics are the main focus of the research. Within these topics, multiple novel contributions are made, which target different layers of the network stack, from the Medium Access Control (MAC) layer to the application layer. The performance of the new Static Context Header Compression (SCHC) protocol was evaluated. As a result, two novel enhancements for SCHC are proposed in order to reduce its memory footprint and improve its compression efficiency. The proposed work improves the performance of SCHC in order to extend the Internet architecture to the LPWANs and thus enabling end-to-end IP connectivity and interoperability. Enabling end-to-end IP connectivity in LPWANs has the potential to bring the power of openness, interconnection, cooperation, and standards to their applications and devices. The performance of the PYH and the MAC layers of LoRaWAN were evaluated, including its adaptive data rate mechanism. This study revealed an unfair data extraction rate among devices, favouring the close ones to the gateway and the ones that use high data rates. Consequently, a novel resource allocation mechanism, FADR, is proposed to enhance the fairness in LoRaWAN by managing the devices’ data rates and transmission power levels. As a result, FADR achieves an almost uniform data extraction rate for all devices regardless of their positions from the gateway and their data rates used. LoRaWAN scalability and agility were studied for data collection applications wherein mobile gateways may participate in the collection processes. The results showed the poor performance of LoRaWAN in dense deployments and in confirmed traffic due to the severe collisions and the duty cycle limitation. To address this, a novel mechanism, called FREE, consists of a time-slotted MAC protocol and a resource management algorithm, was proposed on top of LoRaWAN. FREE manages the resources of the device (i.e. spreading factor, transmission power, frequency channels, etc.) and schedules the transmissions in time slots. As a consequence, FREE overcomes the poor scalability of LoRaWAN and can enable reliable and energy-efficient data collections. The possibility of supporting Firmware Updates Over The Air (FUOTA) was studied on top of LoRaWAN. FUOTA is a critical requirement for any longterm deployments in order to maintain optimal, safe, and secure operations of the network. However, LoRaWAN limitations such as duty cycle, downlink capability, etc. challenge supporting FUOTA. Consequently, A FUOTA process is proposed, exploiting the new specifications to support multicast, fragmentation, and clock synchronization. The proposed FUOTA process is evaluated to quantify the impact of different parameters on the overall performance. This evaluation helped to determine the best FUOTA parameters.
LPWANs , LoRaWAN , IP Interoperability , Resource Management
Hassan, K. Q. A. 2020. Resource management and IP interoperability for low power wide area networks. PhD Thesis, University College Cork.