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

Smart transport layer based mobility for horizontal and vertical handoffs

Mobility management remains an important task to be investigated while integrating homogeneous and heterogeneous wireless networks. Traditionally, IP layer is widely used to implement roaming solutions including Mobile IP, HMIP, FMIP, FHMIP, etc. With the standardization of the Stream Control Transmission Protocol, which offers new interesting features such as multihoming and multistreaming, experiencing mobility at the transport level becomes more attractive. Indeed, this layer is endowed with various connectivity facilities and flow control features that render the transport layer more appropriate to support seamless roaming. To take benefit from these new facilities, several SCTPbased mobility schemes have been proposed. Nevertheless, none can claim to be the ultimate solution since they suffer from drawbacks such as unnecessary handoff delays and signaling loads. Moreover, the throughput measured immediately after a handoff is affected quite considerably by spurious retransmissions due to packet loss and failed Selective Acknowledgment messages (SACKs). In this paper, we propose a smart Hierarchical Transport layer Mobility scheme (sHTM) which deals with homogeneous and heterogeneous handovers, reduces packet loss, handoff latencies and improves throughputs. sHTM exploits the dynamic address reconfiguration feature of SCTP and introduces a new mobility unit to effect more efficient handoff procedures. Simulation results reveal that sHTM guarantees lower handoff latency and good throughput during the handoff period compared to existing mSCTP-based solutions.

A module placement scheme for fog-based smart farming applications

As in Industry 4.0 era, the impact of the internet of things (IoT) on the advancement of the agricultural sector is constantly increasing. IoT enables automation, precision, and efficiency in traditional farming methods, opening up new possibilities for agricultural advancement. Furthermore, many IoT-based smart farming systems are designed based on fog and edge architecture. Fog computing provides computing, storage, and networking services to latency-sensitive applications (such as Agribots-agricultural robots-drones, and IoT-based healthcare monitoring systems), instead of sending data to the cloud. However, due to the limited computing and storage resources of fog nodes used in smart farming, designing a modules placement scheme for resources management is a major challenge for fog based smart farming applications. In this paper, our proposed module placement algorithm aims to achieve efficient resource utilization of fog nodes and reduce application delay and network usage in Fog-based smart farming applications. To evaluate the efficacy of our proposal, the simulation was done using iFogSim. Results show that the proposed approach is able to achieve significant reductions in latency and network usage

Recycling of the Proterozoic crystalline basement in the Coastal Block (Moroccan Meseta): New insights for understanding the geodynamic evolution of the northern peri-Gondwanan realm

Detrital zircon age spectra from the siliciclastic rocks of the Lalla Mouchaa Calcschists and El Jadida Dolomitic formations (the Coastal Block of the Moroccan Meseta) are dominated by Paleoproterozoic and Ediacaran ages. The provenance of these two formations is a composite Proterozoic crystalline basement. El Jadida rhyolite (584.2 ± 4.8 Ma) represents the Ediacaran crystalline basement of the El Jadida dome. El Jadida rhyolite is unconformably overlain by the microbreccia, arkosic sandstone and dolostone of the El Jadida Dolomitic Formation with a maximum depositional age of ca. 539 Ma (Lower Cambrian). Detrital zircon-age spectra from El Jadida Dolomitic Formation (ca. 583–582 Ma) suggest direct recycling of El Jadida rhyolite as an exclusive original primary source. However, in the Western Rehamna massif, detrital zircon-age spectra from pre-Middle Cambrian microbreccia and arkosic sandstone of the Lalla Mouchaa Calcschists Formation (ca. 2.05–2.03 Ga) indicate exclusive recycling of the ca. 2.05 Ga-aged crystalline basement rocks (original primary source). Detrital zircon contents of the siliciciclastic rocks from these two formations of the Coastal Block are consistent with derivation from either Eburnian (Paleoproterozoic) or Cadomian/Pan-African (Ediacaran) igneous rocks. The discovery of this composite Proterozoic crystalline basement in the Moroccan Meseta stresses that Cadomian/ Pan-African magmatic arcs were built on an Eburnian basement in a paleoposition close to the West African craton, as part of the northern peri-Gondwanan realm

Configuration des noeuds d'un réseau mobile ad hoc

Méthodes d'autoconfiguration pour manets -- Protocole d'autoconfiguration pour manets (APM) -- Implémentaire et analyse de performances