Bio-Inspired Tools for a Distributed Wireless Sensor Network Operating System

The problem which I address in this thesis is to find a way to organise and manage a network of wireless sensor nodes using a minimal amount of communication. To find a solution I explore the use of Bio-inspired protocols to enable WSN management while maintaining a low communication overhead. Wireless Sensor Networks (WSNs) are loosely coupled distributed systems comprised of low-resource, battery powered sensor nodes. The largest problem with WSN management is that communication is the largest consumer of a sensor node’s energy. WSN management systems need to use as little communication as possible to prolong their operational lifetimes. This is the Wireless Sensor Network Management Problem. This problem is compounded because current WSN management systems glue together unrelated protocols to provide system services causing inter-protocol interference. Bio-inspired protocols provide a good solution because they enable the nodes to self-organise, use local area communication, and can combine their communication in an intelligent way with minimal increase in communication. I present a combined protocol and MAC scheduler to enable multiple service protocols to function in a WSN at the same time without causing inter-protocol interference. The scheduler is throughput optimal as long as the communication requirements of all of the protocols remain within the communication capacity of the network. I show that the scheduler improves a dissemination protocol’s performance by 35%. A bio-inspired synchronisation service is presented which enables wireless sensor nodes to self organise and provide a time service. Evaluation of the protocol shows an 80% saving in communication over similar bio-inspired synchronisation approaches. I then add an information dissemination protocol, without significantly increasing communication. This is achieved through the ability of our bio-inspired algorithms to combine their communication in an intelligent way so that they are able to offer multiple services without requiring a great deal of inter-node communication.Open Acces

Towards the Practical Implementation of Throughput-Optimal Traffic Engineering in Software Defined Networks

Broadband Wireless Networking topics: 5G, wireless underground sensor networks, software defined networkingThe new emerging networking paradigm of Software Defined Networks, a solution that separates the network control plane from the data forwarding plane, has been the main focus of recently research works. Nevertheless, Traffic Engineering is an important problem to optimize the network performance, especially for a centralized controlled network such as the SDN, by dynamically analyzing, predicting, and regulating the behavior of data transmitted over that network. Therefore, a first version of a new TE management tool called TECS-SENNA - Traffic Engineering Control System for SDN/OpenFlow Networks - is being developed. The connection of TEs with the tool provides a dynamically and globally optimized network resource allocation in such a way that the overall performance can be improved, including throughput, latency, stability, and load balancing, while satisfying the per-flow QoS requirements.El nuevo paradigma de redes emergente llamado Software Defined Networks, una solución que separa el plano de control del plano de envío de datos, ha sido el único foco principal de las recientes investigaciones. Sin embargo, la ingeniería de tráfico es un problema importante para optimizar el rendimiento de la red, especialmente para redes centralizadas y controladas como las redes SDN, analizando, prediciendo y regulando dinámicamente el comportamiento de los datos transmitidos a través de la red. Por eso, en este proyecto se ha construido una primera versión de una nueva herramienta de gestión de ingeniería de trafico llamada TECS-SENNA – Traffic Engineering Control System for SDN/OpenFlow Networkds. La conexión de ingeniería de tráfico con la herramienta proporciona una optimización de la asignación de recursos de red de manera global y dinámica, para que el rendimiento pueda ser mejorado, incluyendo la candencia, la latencia, la estabilidad y el equilibrio de carga, y satisfaciendo los requisitos por flujo de la cualidad de servicio.El nou paradigma de xarxes emergent anomenat Software Defined Networks, una solució que separa el pla de control del pla d’enviament de dades, ha estat l’únic focus principal de les recerques recentment. Però l’enginyeria de trànsit és un problema important per tal d’optimitzar el rendiment de la xarxa, especialment per xarxes centralitzades i controlades com les xarxes SDN, analitzant, fent prediccions i regulant dinàmicament el comportament de les dades transmeses a través de la xarxa. Per això, en aquest projecte s’ha construït una primera versió d’una nova eina de gestió d’enginyeria de trànsit anomenada TECS-SENNA – Traffic Engineering Control System for SDN/OpenFlow Networks. La connexió de l’enginyeria de trànsit amb l’eina proporciona una optimització de l’assignació de recursos de xarxa de manera global i dinàmica per tal que el rendiment pugui ser millorat, incloent la cadència, la latència, l’estabilitat i l’equilibri de càrrega i satisfent els requisits per flux de qualitat de servei

Techniques for Decentralized and Dynamic Resource Allocation

abstract: This thesis investigates three different resource allocation problems, aiming to achieve two common goals: i) adaptivity to a fast-changing environment, ii) distribution of the computation tasks to achieve a favorable solution. The motivation for this work relies on the modern-era proliferation of sensors and devices, in the Data Acquisition Systems (DAS) layer of the Internet of Things (IoT) architecture. To avoid congestion and enable low-latency services, limits have to be imposed on the amount of decisions that can be centralized (i.e. solved in the ``cloud") and/or amount of control information that devices can exchange. This has been the motivation to develop i) a lightweight PHY Layer protocol for time synchronization and scheduling in Wireless Sensor Networks (WSNs), ii) an adaptive receiver that enables Sub-Nyquist sampling, for efficient spectrum sensing at high frequencies, and iii) an SDN-scheme for resource-sharing across different technologies and operators, to harmoniously and holistically respond to fluctuations in demands at the eNodeB' s layer. The proposed solution for time synchronization and scheduling is a new protocol, called PulseSS, which is completely event-driven and is inspired by biological networks. The results on convergence and accuracy for locally connected networks, presented in this thesis, constitute the theoretical foundation for the protocol in terms of performance guarantee. The derived limits provided guidelines for ad-hoc solutions in the actual implementation of the protocol. The proposed receiver for Compressive Spectrum Sensing (CSS) aims at tackling the noise folding phenomenon, e.g., the accumulation of noise from different sub-bands that are folded, prior to sampling and baseband processing, when an analog front-end aliasing mixer is utilized. The sensing phase design has been conducted via a utility maximization approach, thus the scheme derived has been called Cognitive Utility Maximization Multiple Access (CUMMA). The framework described in the last part of the thesis is inspired by stochastic network optimization tools and dynamics. While convergence of the proposed approach remains an open problem, the numerical results here presented suggest the capability of the algorithm to handle traffic fluctuations across operators, while respecting different time and economic constraints. The scheme has been named Decomposition of Infrastructure-based Dynamic Resource Allocation (DIDRA).Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

Qualité de service dans des environnements réseaux mobiles, contraints et hétérogènes

Les télécommunications sans fil ont connu ces dernières années un immense succès à tel point que le spectre des fréquences est désormais surchargé et nécessite la disponibilité de nouvelles ressources. Pour répondre à ce besoin, des techniques de réutilisation dynamique du spectre ont alors vu le jour sous la dénomination de radio cognitive. Elles consistent à partager de manière opportuniste et efficace certaines fréquences ayant été initialement allouées à d'autres systèmes. Cette thèse se place dans le contexte de réseaux sans fil tactiques hétérogènes comportant des segments de radios cognitives. La difficulté provient alors de la garantie de qualité de service de bout en bout : respect du débit négocié, du délai et de la gigue. Nous nous sommes tout d'abord intéressés au contrôle d'admission dans ce type de réseaux en proposant une méthode de calcul de bande passante résiduelle de bout en bout s'appuyant sur un algorithme de complexité polynomiale et pouvant être implanté de manière distribuée. Nous nous sommes ensuite concentrés sur le routage en proposant une nouvelle métrique tenant compte des particularités de ce type de réseaux. Enfin, nous nous focalisons sur la thématique du routage à contraintes multiples en étudiant et implantant en environnement réel des algorithmes d'approximation proposés dans la littérature. ABSTRACT : The unprecedented success of wireless telecommunication systems has resulted in the wireless spectrum becoming a scarce resource. Cognitive Radio systems have been proposed as the enabling technology allowing unlicensed equipments to opportunistically access the licensed spectrum when not in use by the licensed users. The focus of this thesis is on heterogeneous tactical networks deploying cognitive radios in parts or in their entirety. Such networks can be organized in multiple sub-networks, each characterized by a specific topology, medium access scheme and spectrum access policy. As a result, providing end-to-end Quality of Service guarantees in terms of bandwidth, delay and jitter, emerges as a key challenge. We first address the admission control in multi-hop cognitive radio networks and propose a polynomial time algorithm that can be implemented in a distributed fashion for estimating the end-to-end bandwidth. Then, we focus on routing and propose a new metric that takes into account the specifics of such networks. Finally, as quality of service requirements can be expressed using multiple metrics, we turn our attention to multi-constrained routing and implement on a real testbed low complexity approximation algorithms