Cross layer metrics for improving transport protocols in multihop wireless networks

Session Posters & DemosInternational audienceNotre travail s'inscrit dans l'amélioration des protocoles de transport dans les réseaux sans fil ad hoc multisauts. Nous présentons différentes métriques provenant des couches physiques ou liaison pour améliorer les performances de la phase de contrôle de congestion de TCP. Ce papier introduit une classification des métriques inter-couches pour améliorer le niveau transport

MAC-aware rate control for transport protocol in multihop wireless networks

International audienceTransport layer performance in IEEE 802.11 mul-tihop wireless networks (MHWNs) has been greatly challenged by wireless medium characteristics and multihop nature which are the sources of several types of packet loss including collision, random channel errors and route failures. Rate control transport protocols, the candidates for multimedia streaming applications suffer from high loss rates and end-to-end delay in MHWNs. A common research direction is that the rate control mechanisms at transport layer should be aware of MAC layer contention to keep the network load at a reasonable level. In this paper, we introduce a new MAC metric which reflects the contention and congestion levels more accurately. The metric is then used to improve the rate control mechanism of a rate-based transport protocol in MHWNs. The simulation results show that the adapted mechanism introduces significant performance improvement in MHWNs

Allocation équitable de ressources dans les réseaux ad hoc OFDMA

Session Posters & DemosInternational audienceLa technique de partage OFDMA permet d'allouer des ressources discrètes aux communications. Dans cet article, nous présentons un nouvel algorithme distribué d'allocation des Ressource Blocks dans un réseau ad hoc OFDMA. Nous considérons une allocation des ressources sur les liens et un modèle d'inter- férence à deux sauts. Les performances de notre algorithme sont évaluées par simulation et les résultats sont comparés à des bornes théoriques

A Composite Mobility Model for Ad Hoc Networks in Disaster Areas

Ad hoc network is an essential means of communication in disaster scenes. Validation of new communication protocols for these networks requires exhaustive simulation runs because real life experiences can be performed exclusively during expensive civil protection exercises. The necessity of these simulations calls for realistic and reliable mobility models which take into account numerous aspects of rescue worker interventions. We propose a composite model of mobility for disaster scenarii which includes a realistic model of human displacement, team mobility, and obstacle avoidance. The comparison of its performance with those of other available models is encouraging. We believe that it can improve the veracity of rescue operation simulations

Anticipation of ETX Metric to manage Mobility in Ad Hoc Wireless Networks

International audienceWhen a node is moving in a wireless network, the routing metrics associated to its wireless links may reflect link quality degrada- tions and help the routing process to adapt its routes. Unfortunately, an important delay between the metric estimation and its inclusion in the routing process makes this approach inefficient. In this paper, we intro- duce an algorithm that predicts metric values a few seconds in advance, in order to compensate the delay involved by the link quality measurement and their dissemination by the routing protocol. We consider classical metrics, in particular ETX (Expected Transmission Count) and ETT (Expected Transmission Time), but we combine their computations to our prediction algorithm. Extensive simulations show the route enhance- ment as the Packet Delivery Ratio (PDR) is close to 1 in presence of mobility

Metric Anticipation in Mobile Ad-Hoc Networks

International audienceIn this paper, we propose a new method for metric calculations. It aims to improve mobility management in wireless networks. The idea consists in anticipating metric values in order to compensate the delay generated by the measure of the link quality and the routing protocols. As an example, we consider the popular ETX (Expected Transmission Count) metric. We focus on ad-hoc networks, even if our approach could be used in other contexts. We show by simulations that our approach, when well parametrized, allows a Packet Delivery Ratio (PDR) close to 100% when nodes are moving

Hiérarchisation dans les réseaux ad hoc de véhicules

National audienc

Throughput Limits in Spectrum Sensing Cognitive Radio Networks Using Point Processes

8International audienc