Throughput capacity of two-hop relay MANETs under finite buffers

Since the seminal work of Grossglauser and Tse [1], the two-hop relay algorithm and its variants have been attractive for mobile ad hoc networks (MANETs) due to their simplicity and efficiency. However, most literature assumed an infinite buffer size for each node, which is obviously not applicable to a realistic MANET. In this paper, we focus on the exact throughput capacity study of two-hop relay MANETs under the practical finite relay buffer scenario. The arrival process and departure process of the relay queue are fully characterized, and an ergodic Markov chain-based framework is also provided. With this framework, we obtain the limiting distribution of the relay queue and derive the throughput capacity under any relay buffer size. Extensive simulation results are provided to validate our theoretical framework and explore the relationship among the throughput capacity, the relay buffer size and the number of nodes

Information dissemination algorithms in space deployed ad hoc networks

Based on recent trends, in the next few years there could be a lot of cheap devices placed on the surface of different luminaries like the planet Mars instead of sending one or two expensive space-probes. If there are many cheap instruments on the surface of a planet, it is worth using ad hoc networks. For such a network, using energy saving and robust solutions is crucial. We need a local and automatic coordination because of the far distance and the delays appearing in the interplanetary communication. We have dealt with a special type of ad hoc networks and constructed an information dissemination algorithm called SPIO which can collect and exchange data on a distant planet faster than the nowadays used point-to-point systems

Performance modelling of opportunistic forwarding under heterogenous mobility

The Delay Tolerant Networking paradigm aims to enable communications in disconnected environments where traditional protocols would fail. Oppor- tunistic networks are delay tolerant networks whose nodes are typically the users\u27 personal mobile devices. Communications in an opportunistic network rely on the mobility of users: each message is forwarded from node to node, according to a hop-by-hop decision process that selects the node that is better suited for bringing the message closer to its destination. Despite the variety of forwarding protocols that have been proposed in the recent years, there is no reference framework for the performance modelling of opportunistic for- warding. In this paper we start to ll this gap by proposing an analytical model for the rst two moments of the delay and the number of hops expe- rienced by messages when delivered in an opportunistic fashion. This model seamlessly integrates both social-aware and social-oblivious single-copy for- warding protocols, as well as dierent hypotheses for user contact dynamics. More specically, the model can be solved exactly in the case of exponential and Pareto inter-meeting times, two popular cases emerged from the liter- ature on human mobility analysis. In order to exemplify how the proposed framework can be used, we discuss its application to two case studies with dierent mobility settings. Finally, we discuss how the framework can be also solved exactly when inter-meeting times follow a hyper-exponential distribu- tion. This case is particularly relevant as hyper-exponential distributions are able to approximate the large class of high-variance distributions (distribu- tions with coecient of variation greater than one), which are those more challenging, e.g., from the delay standpoint

Performance modelling of opportunistic forwarding with exact knowledge

The Delay Tolerant Networking paradigm aims to enable communications in disconnected environments where traditional protocols would fail. Opportunistic networks are delay tolerant networks whose nodes are typically the users\u27 personal mobile devices. Communications in an opportunistic network rely on the mobility of users: each message is forwarded from node to node, according to a hop-by-hop decision process that selects the node that is better suited for bringing the message closer to its destination. Despite the variety of forwarding protocols that have been proposed in the recent years, there is no reference framework for the performance modelling of opportunistic forwarding. In this paper we start to fill this gap by proposing an analytical model for the expected delay and the expected number of hops experienced by messages when delivered in an opportunistic fashion. This model seamlessly integrates both social-aware and social-oblivious single-copy forwarding protocols, as well as different hypotheses for user contact dynamics. The proposed framework is used to derive bounds on the expected delay under homogeneous and heterogeneous contact patterns. We found that, in heterogeneous settings, finite expected delay can be guaranteed not only when nodes\u27 inter-meeting times follow an exponential or power law with exponential cut-off distribution, but also when they are power law distributed, as long as weaker conditions than those derived by Chaintreau et al. [1] for the homogeneous scenario are satisfied

Self-Evaluation Applied Mathematics 2003-2008 University of Twente

This report contains the self-study for the research assessment of the Department of Applied Mathematics (AM) of the Faculty of Electrical Engineering, Mathematics and Computer Science (EEMCS) at the University of Twente (UT). The report provides the information for the Research Assessment Committee for Applied Mathematics, dealing with mathematical sciences at the three universities of technology in the Netherlands. It describes the state of affairs pertaining to the period 1 January 2003 to 31 December 2008

A Study on Throughput and Delay Performance Analysis in Two-Hop Relay Mobile Ad Hoc Networks

Tohoku University加藤寧課

Communications multi-niveaux sécurisées dans une flotte de terminaux mobiles

Les matériels mobiles actuels, et les téléphones mobiles en particulier, sont équipés de différentes technologies sans fil qui augmentent et diversifient leurs capacités de communication. L utilisation combinée et efficace de ces technologies offre des possibilités variées et accrues en termes de services et d applications. Néanmoins elle requiert la réalisation d analyses fines en matières de sécurité et de choix du mode de communication à utiliser en fonction de critères dépendant du contexte : coût énergétique, coût financier, préférences des entités impliquées, préservation de la vie privée, etc. Cette problématique est apparue comme une question clé au sein du projet Smart Urban Spaces dans le cadre duquel s inscrit cette thèse. Notre contribution à ce projet est la création d applications collaboratives qui utilisent de façon appropriée la gamme des technologies sans fil disponibles sur les matériels considérés. En d autres termes, on cherche à utiliser les moyens de transmission les plus appropriés (au sens des critères indiqués plus haut) que deux ou plusieurs équipements mobiles peuvent utiliser pour réaliser leurs échanges, qui plus est, sans que cela ne nécessite de connaître leurs positions respectives. La transparence de la localisation des cibles devient ainsi une règle. On peut synthétiser la question centrale que nous avons choisie d étudier de la manière suivante : comment faire communiquer un ensemble de terminaux mobiles (des téléphones portables en particulier) de façon sécurisée en utilisant la technologie la plus adaptée en fonction du contexte ? Notre objectif est de proposer une réponse à cette question en définissant une plate-forme multi-niveaux prenant en compte les différentes technologies disponibles sur les équipements considérés. Il s agit en particulier d identifier l ensemble des éléments à prendre en compte dans la conception de la plate-forme, de les modéliser, de développer des applications de référence et de valider la pertinence des solutions proposées par des tests, ainsi que des évaluations qualitatives et quantitatives.Current mobile devices, and mobile phones in particular, are equipped with different wireless technologies that increase and diversify their communication capabilities.The combined and effective use of these technologies offers various opportunities in terms of services and applications. However, it requires detailed analysis in terms of security and choice of the communication mean to use according to context-dependent criteria : energy costs, financial costs, preferences of the involved entities, privacy issues, etc. This problem has emerged as a key issue in the Smart Urban Spaces project in which this thesis was carried out. Our contribution to this project is the creation of collaborative applications adequately using the available wireless technologies on the considered equipments. In other words, we try to use the most appropriate communication mean (according to the criteria listed above) that two or more mobile devices can use to perform exchanges (without considering their respective positions). Then, the transparency of targets localization becomes a rule.We can synthesize the central question that we have chosen to study in the following manner : how to allow a set of mobile terminals (mobile phones in particular) to securely communicate using the most appropriate technology depending on the context ? Our goal is to answer this question by defining a multilevel platform taking into account the different technologies available on the considered equipments. It is necessaty to identify the elements to consider in the design of the platform, to model them, to develop reference applications and to validate the relevance of the proposed solutions with qualitative and quantitative evaluations.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF