Abstract:
Wireless Sensor Networks have been enabling a large bandwagon of applications and usage in the industrial, domestic and commercial areas. Advancements in microelectronics and communication technologies during the past decade has been fueling the increasing pervasiveness and ubiquity of these infrastructures, eventually paving a way to support the paradigm of Internet of Things. Specifically in the industrial domain, there are applications which put-forth strict requirements in terms of timeliness and reliability. Other QoS properties such as scalability, energy efficiency and robustness must also be taken into concern when pushing these infrastructures towards a possible reality. This thesis explores the functionalities of the IEEE 802.15.4e MAC behaviors, keeping the the Deterministic Synchronous Multi-channel Extension (DSME) as the major focus. The legacy IEEE 802.15.4 standard was enhanced by the IEEE 802.15.4e with the augmentation of functionalities such as frequency hopping, dedicated and shared timeslots and several techniques to improve scalability and the energy efficiency of the application. In this thesis we present some architectural solutions (mechanisms, algorithms, protocol add-ons) that can address some of the most prominent Quality of Service (QoS) challenges in terms of timeliness, scalability, robustness and energy-efficiency
In order to efficiently address the network demands, in terms of QoS aspects such as latency, resources, and reliability, it is mandatory to carry out a thorough network planning. Modeling the fundamental performance limits of the networks is of paramount importance to understand their behavior under the worst-case conditions and to make the appropriate design choices. In this thesis, we accurately compute the worst case bounds of a network and provide a deep insight towards applications which these MAC behaviors would suit based on their respective network architectural properties.
In regards with timeliness, the IEEE 802.15.4 was one the legacy standards that introduced the concept of guaranteed timeslots to ensure time bounded communication. The DSME and TSCH MAC behaviors of the IEEE 802.15.4e improved more in this front by proving multi-channel access and increasing the available bandwidth, and concurrently increasing scalability. However, there lies a challenge in scheduling the guaranteed timeslots stringently and using the capabilities of the standard to its fullest extent. This thesis provides scheduling mechanisms and cross-layer architectures to reduce the overall latency and improve the reliability and reduce the power consumption of the network.
As we now move towards the paradigm of increased pervasiveness in the field of Wireless Sensor Networks, there is a need for architectures that have the capability to adapt on run-time to suit the prerequisites of the underlying application. Despite the capability to support complex networks, there is a need for adaptable infrastructures to provide good QoS without any dire trade-offs. In this thesis, we provide one such mechanism that can alter the network infrastructure based on its demands.
As the DSME protocol has the capability to facilitate communication with bounded time, it opens possibilities of adaption into several time-critical application domains. In this thesis, we explore the possibility of the adaption of the DSME protocol for time and safety critical Advanced driving assistance systems (ADAS) systems. To effectively test and validate these systems, there is a need for tools that can support the simulation of these complex communication infrastructures from the control and the networking perspective. This thesis introduces a co-simulation framework that enables the simulation of an ADAS application scenario in these two fronts, analyzing the relationship between different vehicle dynamics and the delay required for the system to operate safely, exploring the performance limits of different wireless network configurations.

Authors:


PhD Thesis, FEUP.
Porto.

DOI:https://hdl.handle.net/10216/132005.

Notes: Presidente do Juri Doutor José Alfredo Ribeiro da Silva Matos, Professor Catedrático da FEUP Vogais Doutor Ye-Qiong Song, Professor of the Computer Science, at University of Lorraine, France; Doutor Zdenek Hanzalek, Professor at Institute of Informatics, Robotics and Cybernetics of the Czech Technical University, Prague; Doutor Eduardo Manuel Medicis Tovar, Professor Coordenador do Departamento de Engenharia Informática do Instituto Superior de Engenharia do Instituto Politécnico do Porto (Orientador); Doutor Paulo José Lopes Machado Portugal, Professor Associado do Departamento de Engenharia Eletrotécnica e de Computadores da Faculdade de Engenharia da Universidade do Porto; Doutor Pedro Alexandre Guimarães Lobo Ferreira Souto, Professor Auxiliar do Departamento de Engenharia Informática da Faculdade de Engenharia da Universidade do Porto.



Record Date: 30, Dec, 2020