Design and Performance Evaluation of IAR: Interference-Aware Routing Metric for Wireless Mesh Networks

Multihop wireless mesh networks are an attractive solution for providing last-mile connectivity. However, the shared nature of the transmission medium makes it challenging to fully exploit these networks. In an attempt to improve the radio resource utilization, several routing metrics have been specifically designed for wireless mesh networks. However none of these routing metrics efficiently tackles interference issues. Moreover, although some evaluations have been conducted to assess the performance of these metrics in some contrived scenarios, no overall comparison has been performed. The contributions of this paper are consequently twofold. First, we propose a new routing metric, Interference-Aware Routing metric (IAR), specifically designed for WMNs. IAR uses MAC-level information to measure the share of the channel that each link is able to utilize effectively. As a result, paths that exhibit the least interference will be selected to route the data traffic. Then we evaluate the performance of IAR against some of the most popular routing metrics currently used in wireless mesh networks: Hop Count, Blocking Metric, Expected Transmission Count (ETX), Expected Transmission Time (ETT), Modified ETX (mETX), Network Allocation Vector Count (NAVC) and Metric of Interference and Channel-Switching (MIC). We show under various simulation scenarios that IAR performs the best in terms of end-to-end delay and packet loss, and provides the fairest resource utilization.     

ANN modeling of a smart MEMS-based capacitive humidity sensor

This paper presents a design of a smart humidity sensor. First we begin by the modeling of a Capacitive MEMS-based humidity sensor. Using neuronal networks and Matlab environment to accurately express the non-linearity, the hysteresis effect and the cross sensitivity of the output humidity sensor used. We have done the training to create an analytical model CHS “Capacitive Humidity Sensor”. Because our sensor is a capacitive type, the obtained model on PSPICE reflects the humidity variation by a capacity variation, which is a passive magnitude; it requires a conversion to an active magnitude, why we realize a conversion capacity/voltage using a switched capacitor circuit SCC. In a second step a linearization, by Matlab program, is applied to CHS response whose goal is to create a database for an element of correction “CORRECTOR”. After that we use the bias matrix and the weights matrix obtained by training to establish the CHS model and the CORRECTOR model on PSPICE simulator, where the output of the first is identical to the output of the CHS and the last correct its nonlinear response, and eliminate its hysteresis effect and cross sensitivity. The three blocks; CHS model, CORRECTOR model and the capacity/voltage converter, represent the smart sensor.     

Recovery and enrichment of heavy metals using new hybrid Donnan dialysis systems combining cation exchange textile and solvent impregnated resin

The purpose of this work is to apply Donnan dialysis coupled with the cation exchange membrane (CMX), the cation exchange grafted textile (CET) and the solvent impregnated resin (SIR) for recovery and enrichment of heavy metal ions from dilute solutions. The influence of some analytical parameters was investigated. The transport results show that the three barriers enhance the diffusion of silver, lead and copper, but the osmosis phenomenon is limited when the transport is carried out through CET and the SIR. The results of enrichments indicate that SIR and CET increase the enrichment factor of less hydrated ions. For instance, and for a volume ratio equal to 10, the values of silver enrichment factor obtained for (CMX/CMX/CMX), (CMX/CET/CMX) and (CMX/SIR/CMX) are equal to 2.5, 8.92 and 4.98, respectively. In addition, the use of SIR improves the enrichment of lead, whereas the CET improves the silver’s one.     

A Novel Dimension of Cooperation in 4G

The Fourth Generation (4G) of wireless networks is no longer a dream; it is knocking now at the doors of our information village. 4G promises to offer a vast range and diversity of converged devices, services, and networks and to revolutionize the way we communicate. 4G would influence today's networking architecture where the inter-user communication is realized with the help of third-party communication infrastructure. In 4G, the centralized third-party controlled networking architecture can emerge into a hybrid model, where a part of user-to-user interaction would be envisaged by short/medium range wireless communication systems.     

Cooperation in 4G - Hype or Ripe?

With increasingly congested frequency bands and an ever-growing demand for higher data rates, innovative approaches are needed to increase the spectral efficiency and hence cost per bit/s/Hz overless links. Cooperative systems and radios, which are capable of intelligently forming mutually cooperative entities, are a promising way to achieve this increase in capacity. First technological and then social barriers, however, have prevented us so far from having technologies, systems, or users jointly cooperate. We will try to answer in this article whether the time is ripe for a technology which has recently received so much hype.     

Retour d’expérience sur différentes applications de réseau actif

Active network technologies, started by D. Tennenhouse’s work atmit in 1995 have led a lot of promises on the evolution of data networks. Active networks aim at integrating new application-level functionalities into active nodes within the network, in a flexible and extensible way. The research works on active networks have raised at the same time as the definition of new open network architectures (e.g., Tina model) and the deployment of intelligent networks merging telecom networks with distributed systems fields. This concept of “programmable networks” led to many technology-oriented projects, but has not identified relevant applications highlighting the benefits of the technology. During the three last years, our laboratory has tackled this gap and prototyped some use cases of open programmable networks. The paper gives an overview of each of these use cases and focuses on the integration with existing network elements both at transfer and management planes. Then it presents some assessments and perspectives. We show that programmable networks are optimizing globally resources to be deployed although they impose an overhead at node level, thanks to efficient integration choices. We present two scenarios of deployment of current programmable network platforms within the same network configuration than a realwan network.