A framework for fast handoff schemes in wireless ATM networks

Includes bibliographical references.In this research, we focus on providing a framework that extends the fixed ATM standard to support user mobility in future WATM networks. The WATM architecture allows for the migration of fixed ATM networks without major modifications. Thus most of the mobility functions are implemented on the wireless access network. The most important component supporting mobility in a cluster is the Mobility Enhanced Switch (MES). We propose using direct links between adjacent MESs to support Permanent Virtual Channels (PVCs) in order to facilitate fast inter-cluster handoffwith minimum handofflatency. This research addresses a framework on handoff mobility by proposing three fast handoff re-routing schemes based on the support of PVCs

A Study of Sojourn Time for Indoor LiFi Cellular Networks

Sojourn time is an important parameter in the analysis and design of mobile cellular networks. It shows the expected time that a user equipment (UE) remains connected to the serving access point (AP) while moving in the network, i.e. stays within one cell. Therefore, an accurate estimation of the sojourn time is an essential element for mobility management. In this study, an analysis of the sojourn time for indoor light-fidelity (LiFi) cellular networks is presented based on the random waypoint (RWP) mobility model. It is initially assumed that the UE is oriented vertically upward and closed-form analytical expressions are derived. Monte-Carlo simulations are also provided to validate the analytical derivations and to gain more insight into the performance with different orientations. It is shown that the sojourn time mainly varies depending on the speed of the user. However, other factors such as the device orientation and the coverage area of cells also play a role in determining the sojourn time. The results offer several insights and design guidelines in consideration of this parameter for indoor LiFi networks

Intégration et gestion de mobilité de bout en bout dans les réseaux mobiles de prochaine génération

Résumé - Pendant les dix dernières années, l'utilisation des systèmes de communication sans fil est devenue de plus en plus populaire tant chez les entreprises que chez les particuliers. Cette nouvelle tendance du marché est due, en grande partie, à la performance grandissante des réseaux mobiles qui concurrencent davantage les réseaux filaires en termes de bande passante, de coût et de couverture. Toutefois, cette catégorie de solutions sans fil est conçue pour des services spécifiques et utilise des technologies très variées. De plus, les usagers sont de plus en plus mobiles et requièrent des applications sensibles au délai (voix, multimédia, etc.). Dans ce nouveau contexte de mobilité, la prochaine génération des réseaux sans fil (4G) s'annonce comme l'ultime solution visant à satisfaire les exigences des usagers tout en tirant profit de la complémentarité des services offerts par les systèmes mobiles existants. Pour ce faire, la principale vocation de la future génération (4G) consiste en l'intégration et la convergence des technologies sans fil existantes et celles à venir. Cette intégration passe obligatoirement par l'utilisation du protocole IP (Internet Protocol) qui permet de cacher l'hétérogénéité des systèmes intégrés puisqu'il demeure l'unique couche commune à toutes les plateformes mobiles. Plusieurs solutions d'intégration ont été proposées dans la littérature. Celles-ci concernent des architectures d'intégration et des mécanismes de gestion de mobilité. Cependant, les approches proposées ne font pas l'unanimité et souffrent de plusieurs handicaps liés, en particulier, à l'interopérabilité et la garantie des relèves sans coupures.----------ABSTRACT During the last few years, the use of wireless systems is becoming more and more popular. This tendency can be explained by the fact that mobile technologies are gaining in performance in terms of bandwidth, coverage and cost compared to the traditional wired solutions. However, each mobile network is tailored for a specific type of services and users. Moreover, end users are expected to become more and more mobile and show an increasing interest to real-time applications. In these circumstances, the next generation of mobile networks (4G) appears to be the ultimate solution that will satisfy mobile user demands and take benefit of the existing wireless systems. Indeed, the future generation consists of integrating, in an intelligent manner, the existing/future wireless systems in a way that users can obtain their services via the best available network. This integration passes through the use of the Internet Protocol (IP) that will hide the heterogeneity pertaining to the integrated networks. To deal with this very important task, several solutions are available in the literature. The proposed approaches cover some basic topics such as interworking architecture and mobility management. Nevertheless, these proposals suffer from drawbacks relevant to the guarantee of QoS through heterogeneous technologies

Analytical modeling of HSUPA-enabled UMTS networks for capacity planning

In recent years, mobile communication networks have experienced significant evolution. The 3G mobile communication system, UMTS, employs WCDMA as the air interface standard, which leads to quite different mobile network planning and dimensioning processes compared with 2G systems. The UMTS system capacity is limited by the received interference at NodeBs due to the unique features of WCDMA, which is denoted as `soft capacity'. Consequently, the key challenge in UMTS radio network planning has been shifted from channel allocation in the channelized 2G systems to blocking and outage probabilities computation under the `cell breathing' effects which are due to the relationship between network coverage and capacity. The interference characterization, especially for the other-cell interference, is one of the most important components in 3G mobile networks planning. This monograph firstly investigates the system behavior in the operation of UMTS uplink, and develops the analytic techniques to model interference and system load as fully-characterized random variables, which can be directly applicable to the performance modeling of such networks. When the analysis progresses from single-cell scenario to multi-cell scenario, as the target SIR oriented power control mechanism is employed for maximum capacity, more sophisticated system operation, `feedback behavior', has emerged, as the interference levels at different cells depend on each other. Such behaviors are also captured into the constructed interference model by iterative and approximation approaches. The models are then extended to cater for the features of the newly introduced HSUPA, which provides enhanced dedicated channels for the packet switched data services such that much higher bandwidth can be achieved for best-effort elastic traffic, which allows network operators to cope with the coexistence of both circuit-switched and packet-switched traffic and guarantee the QoS requirements. During the derivation, we consider various propagation models, traffic models, resource allocation schemes for many possible scenarios, each of which may lead to different analytical models. All the suggested models are validated with either Monte-Carlo simulations or discrete event simulations, where excellent matches between results are always achieved. Furthermore, this monograph studies the optimization-based resource allocation strategies in the UMTS uplink with integrated QoS/best-effort traffic. Optimization techniques, both linear-programming based and non-linear-programming based, are used to determine how much resource should be assigned to each enhanced uplink user in the multi-cell environment where each NodeB possesses full knowledge of the whole network. The system performance under such resource allocation schemes are analyzed and compared via Monte-Carlo simulations, which verifies that the proposed framework may serve as a good estimation and optimal reference to study how systems perform for network operators