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International audience; Cloud Radio Access Network is foreseen as one of the key features of the future 5G mobile communication standard. In this context, all the baseband processing is intended to be performed on CPUs in order to keep a high level of flexibility. The challenge is then to propose efficient software implementations of baseband processing algorithms that guarantee a sufficient throughput, while limiting the energy consumption. In this paper, as an alternative to general purpose processors, we propose an implementation of an Application Specific Instruction set Processor customized for the Successive Cancellation decoding of polar codes. The resulting software decoder achieves throughputs similar to state-of-the-art ARM processor implementations, while reducing the energy consumption by a factor 10.

International audience; Fluorine is produced from electrolysis of KF/HF mixtures at around 95°C. In the cell configuration, carbon anodes are screwed onto a copper busbar. Much attention has been paid to the stability of copper since the corrosion and re-deposition of this metal on the cathodes is one of the main factors (side reaction) which limit the production yield of fluorine gas, the lifetime of the cells and the development of new electrolyzers. Therefore, in the frame of this study, various experiments were carried out to determine the corrosion rate of copper for a wide range of HF ratio and temperature. A statistics approach of the electrochemical data allowed us to predict the corrosion rate for many the operating conditions. At OCV, copper shows a good corrosion resistance even for high HF ratios. However, under a 6 V anodic polarization, copper corrosion rate raises drastically with an increase of the temperature and / or the HF ratio. Characterization techniques have shown that only a thin copper fluoride layer has been detected on copper at OCV. By contrast, two types of copper fluorides were evidenced at the electrode surface (CuF2 and KCuF3) when a potential was applied to Cu. Under anodic polarization, a thin CuF2 layer is formed at the copper surface whereas KCuF3 is detected at on the electrode surface resulting from the precipitation of Cu2+. For a better interpretation of the results, erosion-corrosion phenomenon issued from the fluorine bubbles impacts and electrolyte movements has been highlighted by weight losses of copper pieces. The breakdown of the passivation layer on copper and the exposition of the surface to the corrosive medium imply a quicker degradation of the metallic pieces.

In the past few years, the concept of pervasive connectivity has become of crucial importance. New protocols have therefore been standardized to enable IPv6 mobility, such as the Network Mobility Basic Support (NEMO BS) protocol. This protocol is particularly suited for providing a global IPv6 connectivity in intelligent transportation systems. Yet, despite its popularity and maturity, it still suffers from various limitations which prevent its adoption in large-scale commercial deployments. Among these are operator specific issues such as the lack of practical and efficient bootstrapping procedure. Also, a global connectivity enables the provision of value-added services whose attractiveness mainly depends on their ease of configuration. In this paper, we focus on solutions to address both the bootstrapping of NEMO BS and service discovery in a mobile environment. By investigating various bootstrapping proposals, we advocate the use of a standardized solution extended with the missing pieces to operate in a NEMO BS environment. We also expose how operator services could be exported and announced in the mobile subnet. Authentication and authorization to access these services are also investigated. Experiments on a prototype show that our proposal brings the missing blocks towards the deployment of network mobility service in intelligent transportation systems. Copyright © 2009 John Wiley & Sons, Ltd.

La fourniture de services IP a valeur ajoutee requiert des fonctions service sophistiquees, devant etre sollicitees de maniere coherente et dans un certain sequencement afin de satisfaire les besoins clients ainsi que les exigences et contraintes des operateurs. Contrairement aux pratiques actuelles ne permettant pas un deploiement de services sans impact sur le reseau sous-jacent, le mecanisme de chainage de fonctions service (SFC) permet de s'affranchir de l'adherence au reseau de transport et offre une grande flexibilite pour structurer des services avances d'une maniere dynamique et evolutive. Cet article decrit les motivations et l'essence du mecanisme de chainage fonctionnel, identifie une liste de cas d'usage emblematiques et en extrait les besoins fonctionnels a satisfaire par un systeme SFC.

The Transmission Control Protocol (TCP) is one of the core components of the TCP/IP protocol suite. It has been extensively used for the past three decades (and counting) as the privileged connection-oriented transport mode for many Internet applications, including access to web contents. Nevertheless, experience with TCP can sometimes be rather poor for various reasons which include (but are not limited to) sub-optimized forwarding path capabilities. Because a TCP session can only be established over a single path (by definition), this restriction is not only unable to take into account the dramatic evolution of terminal technologies towards multi-interfaced devices, but also the ability to benefit from several yet potential forwarding paths for the sake of improved Quality of Experience (QoE).

Cet article presente les options permettant d’introduire IPv6 dans les infrastructures mobiles, tout en garantissant que les utilisateurs mobiles aient toujours acces aux applicatifs IPv4. En particulier les strategies double pile et IPv6-only sont approfondies. Les problematiques de securite associees a l’introduction d’IPv6 sont ensuite proposees. Elles se concentrent, d’une part, sur les principales menaces observees sur les infrastructures mobiles et, d’autre part, sur les vulnerabilites intrinseques liees a la nouvelle version du protocole IP. Quelques recommandations et techniques permettant a un operateur mobile de se premunir contre les principaux risques sont decrites pour conclure cet article.

Internet actors should work on an action plan to mitigate the increase of Routing Information Base (RIB) and Forwarding Information Base (FIB) table sizes and the load induced by routing updates churn (BGP Instability Report, n.d.).

Network selection in an environment of heterogeneous wireless networks (HWNs) has been widely studied, but mobility-related factors were not well considered by selection schemes in the literature. Since vertical handover (VHO) corresponds to permutation of networks, the selection of a network actually becomes the selection of a permutation when VHO properties are considered. In this paper, we propose a best permutation scheme (Basic Besper) for mobility-based network selection in a generic HWN environment and two methods (i.e. Simplified Besper and Enhanced Besper) to further improve the time complexity of Basic Besper. According to our performance evaluations, Bespers could always select the best network and permutation based on mobility-related factors and many advantages compared with classic best network schemes are demonstrated. Furthermore, the two methods (especially Enhanced Besper) could find the best network quite rapidly, which is important for the continuity of real-time applications during VHOs.

Recently, network selection in heterogeneous wireless networks has been widely studied by using various mathematical models, in which MADM is one of the most popular. However, the usage of this model still has lots of existing issues in many scenarios, and there is lack of study on how to solve these issues in the scope of MADM-based network selection. Based on our previous survey, we firstly provide in this paper extensive simulations to demonstrate MADM's feasibility in various scenarios. Meanwhile, we identify several important issues that have not been well solved in the current literature, such as the requirement of efficient weighting method, the usage of VHO properties, the tradeoff for handing-over to the new best network, and the immoderate load balancing compromising importance of other criteria. Combining with our studies on these issues, we finally propose a four-step integrated strategy for MADM-based network selection.

International audience; Network mobility allows nodes to maintain their connections whilst attaching to different access networks. These access networks may be based on different access technologies. The NEMO Basic Support protocol is a generic protocol that can be used in different mobile environments such as bus or train. Yet, access control mechanisms and Authentication, Authorization and Accounting (AAA) architecture have to be set up according to these specific contexts. The fundamental difference, from an operator’s point of view, for access control and AAA considerations, is the ownership of the Mobile Router which is the centric device for network mobility. As such, three deployment scenarios are studied. AAA architectures are proposed and security problems are highlighted for each scenario.

Internet lacks of strong security mechanisms, opening the way to a plethora of different manners in which integrity and availability can be compromised by malicious activities. Furthermore, the trend shows an increase of security threats, at least in the foreseeable future. Despite such situation, new proposals for Future Internet architectures mostly aiming at solving scalability issues do rather neglect security aspects.Among candidate Future Internet architectures, the ones based on the Locator/Identifier separation paradigm has been largely explored but security had no major role in these research activities. We present a security threats analysis of such approach using the Locator/Identifier Separation Protocol (LISP) as a running example.The chapter does not overview the merits of the Locator/Identifier separation paradigm. Rather, the aim is to provide a thorough analysis of the security aspects, assessing the security level of the architecture and providing recommendations on possible practices to improve it.