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Browsing Research Reports by Subject "Ad-hoc network"

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    Efficient Monitoring Mechanisms for Cooperative Storage in Mobile Ad-Hoc Networks : Detection Time and Accuracy Tradeoffs
    (CERIST, 2009-02) Derhab, Abdelouahid; Senouci, Mustapha Reda; Badache, Nadjib
    Distributed cooperative storage systems are designed to share the storage resources of network nodes for the common good of everyone, especially in dynamic ad hoc networks (MANETs) where the risk of data loss is high. In ad hoc networks, as mobile nodes operate on low-power battery and use limited storage capacity, data holders might behave selfishly by discarding some data they promised to store for other nodes in order to optimize their storage space for their own usage. To detect such a behavior, a monitoring mechanism, which checks whether a data is still held by the data holder, must be used. In this paper, we propose novel monitoring mechanisms that consider MANETs constraints and overcome the limitations of the existing monitors. Simulation results show that the proposed mechanism can o er a good trade-off between the rate of false positives and the time to detect misbehaved nodes.
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    SQUIRREL : Self-organizing Qos-roUting for IntRa-flow contention in ad-hoc wiRELess networks
    (CERIST, 2008) Derhab, Abdelouahid
    Due to the shared nature of the wireless medium, contention occurs among the nodes along a multi-hop path, which leads to intra-flow contention. In this paper, we use the selforganizing paradigms presented in [1] to design a new Qos-routing intra-flow contention-based protocol for wireless ad hoc networks, called SQUIRREL. The admission control component of SQUIRREL, called : Scalable and Accurate Admission control (SAICAC), has two variants : SAICAC-Power and SAICAC-CS. SAICAC-Power estimates channel bandwidth availability through high power transmissions and SAICAC-CS through passive monitoring of the channel. SQUIRREL can ensure all the properties of a self-organizing system contrary to the existing intra-flow contention-based protocols. Our analytical study demonstrates that SAICAC can achieve the best results in terms of message overhead, delay, and scalability.