Mécanismes sensibles au contexte pour l’optimisation de la découverte des appareils

Research in communication networks aims to improve the capabilities and performance of network technologies, and to satisfy the ever increasing demand for instant information access and exchange. For example, work on Fifth Generation (5G) Wireless Systems aims to increase data rates and spectral efficiency while lowering latency and energy consumption. Within this context, proximity-based networking is being considered in order to improve the data sharing between nearby devices, regardless of the availability of additional infrastructure. An integral component of these solutions is the ability to quickly detect (or discover) other systems in the vicinity. While system and service discovery has been a concept used in networks for some time, its adoption by wireless networks has increased the importance and relevance of this type of mechanisms. Therefore, the goal of this thesis is to optimize the performance of the discovery process by using context-aware mechanisms. First, we start by an introductory description of the challenges faced by network users and how current solutions (i.e. Long Term Evolution (LTE)) are unable to cover their needs. Second, we present the architecture we will use to evaluate our proposals, namely the device-to-device (D2D) architecture defined by the Third-Generation Partnership Program (3GPP) for use in LTE networks, with an emphasis on the description of the discovery process as defined in the standard specifications. Then, we present an analytical study, along with an implementation model to test and validate the performance of direct discovery. Building upon that analysis, we propose an adaptive transmission algorithm that optimizes the discovery process for static topologies. This contribution is used as the foundation for extended and enhanced algorithms targeting scenarios where the availability of historic data allows for predicting user density fluctuations, and fully dynamic situations without external infrastructure or support, showing how context-aware mechanisms can provide almost optimal performance. All these contributions and analysis are supported and validated by simulation models and experiments that showcase the importance and correctness of our proposals in the optimization of the performance and reliability in D2D direct discoveryLa recherche dans les réseaux de communication cherche à améliorer la capacité et les performances des technologies de réseaux tout en satisfaisant à la fois la demande croissante d’instantanéité des accès et des échanges d’information. Par exemple, les travaux sur les systèmes sans-fil de cinquième génération (5G) visent à augmenter le débit de données et l’efficacité spectrale mais aussi à réduire la latence et la consommation d’énergie. Dans ce contexte, la mise en réseau basée sur la proximité est envisagée afin d’améliorer l’échange d’information entre périphériques proches, même dans le cas où aucune infrastructure n’est disponible. Une composante essentielle de ces solutions est la capacité de rapidement détecter (ou découvrir) les autres systèmes à proximité. Bien que l’utilisation de la découverte des systèmes et de services ne soit pas à proprement parler une nouveauté dans les réseaux, son adoption dans les réseaux sans-fil a augmenté l’importance et la pertinence de ce type de mécanismes. Par conséquence, l’objectif de cette thèse est d’optimiser les performances du processus de découverte en utilisant des mécanismes contextuels. Dans un premier temps, nous commençons par une description préliminaire des défis auxquels sont confrontés les utilisateurs du réseau et comment les solutions actuelles (c’est-à-dire Long Term Evolution (LTE)) ne peuvent pas couvrir leurs besoins. Dans un deuxième temps, nous présentons l’architecture utilisée pour évaluer nos propositions: l’architecture appareil-à-appareil (D2D) qui est définie par le programme de partenariat de troisième génération (3GPP) pour être utilisée dans les réseaux LTE. Nous mettrons tout particulièrement l’accent sur la description du processus de découverte tel qu’il est défini dans les spécifications. Finalement, nous présentons une étude analytique, avec un modèle de mise en oeuvre pour tester et valider les performances de la découverte directe. En utilisant cette analyse, nous proposons un algorithme de transmission adaptatif qui optimise le processus de découverte pour les topologies statiques. Cette contribution sert de base à des algorithmes étendus et améliorés ciblant premièrement des scénarios où la disponibilité de données historiques permet de prédire les fluctuations de la densité des utilisateurs, et deuxièmement des situations entièrement dynamiques sans infrastructure ou support externe, montrant comment les mécanismes contextuels peuvent fournir des performances presque optimales. Toutes ces contributions et ces analyses sont supportées et validées par des modèles de simulation et des expériences qui montrent l’importance et l’exactitude de nos propositions dans l’optimisation de la performance et de la fiabilité dans le cadre de la découverte direct

A Long Term Evolution (LTE) Device-to-Device module for ns-3

International audienceIn this paper, we provide an overview of our ongoing implementation of a 3 rd Generation Partnership Program (3GPP) Proximity Services (ProSe) module in ns-3 to enable the performance evaluation of device-to-device (D2D) discovery and communication in Long Term Evolution (LTE) networks

Implementation and Validation of an LTE D2D Model for ns-3

International audienceThe ability to perform device-to-device (D2D) communication in Long Term Evolution (LTE)-based cellular networks became possible with the introduction of Proximity Services (ProSe) functionalities in the 3rd Generation Partnership Program (3GPP) specifications. In this paper, we provide a description of the ProSe implementation that extends the LTE model already available in ns-3. Our model contains key features defined in LTE Release 12 and further enhanced in LTE Release 13 related to synchronization, discovery, and communication. We also provide validation of each feature by comparing simulation results with analytical models developed as part of our work on D2D communication

Enhancing Device-to-Device direct discovery based on predicted user density patterns

International audienceDevice-to-Device (D2D) direct discovery service is a key component for Proximity Services (ProSe) and D2D communications. Depending on the type of the studied network (pedestrian, vehicular, residential, industrial), large spatio-temporal fluctuation in mobile users' density may occur inducing several patterns throughout the day. The current standards only account for fixed configurations of this service, and currently, the research into adaptive algorithms is done using analytical models and synthetic scenarios and configurations, which makes such solutions perform poorly on real systems. We propose an adaptive D2D discovery algorithm that, building upon existing work on user density prediction analytical models of the discovery process, uses historic network traces to update its operational parameters dynamically. We test the proposed algorithm and compare it to the discovery mechanism, defined in the Third Generation Partnership Project (3GPP) standards, in order to analyze the feasibility of these types of solutions. The simulation results show that the proposed algorithm strikes a balance between network utilization and time required for discovery, which is a very promising starting point for further research on this type of solution

Public Safety Communications: How to Maintain Connectivity and Improve Resiliency?

International audienceEmergency personnel operating in highly stressed environments may find themselves unable to connect to traditional network access points such as cell towers. In such a situation, the ability to maintain communication services when outside of network coverage and in the event of widespread network failures is essential. The Public Safety Communication Research (PSCR) program has been developing modeling and simulation tools to evaluate different functionalities such as the use of high power transmission and device-to-device (D2D) communications. This talk presents key findings associated D2D communications in a public safety context. In addition, we will show strategies to maintain network coverage in the case of equipment failures or infrastructure loss and what traffic can be sustained in this case