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Author: search.filters.author.Khelladi, Lyes

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    Revisiting Directed Diffusion In The Era Of IoT-WSNs : Power Control For Adaptation to High Density
    (IEEE Xplore, 2017-08-28) Khelladi, Lyes
    Wireless Sensor Networks (WSNs) have been recognized as a crucial and enabling technology in the world of Internet of Things (IoT). However, their integration with IoT arises new design challenges, compared to conventional WSNs applications. This paper addresses the challenge of high node density and its impact on the design of IoT-WSNs routing protocols. We propose a power-aware topology control mechanism built upon the prominent routing scheme, Directed Diffusion. Moreover, we take benefit from the power-awareness feature of the topology control mechanism in order to compute an energy consumption metric, allowing the selection of energy-efficient routes. The simulation results demonstrate an improvement by the proposed protocol in terms of energy efficiency, data reporting delays and delivery success rate.
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    Efficient On-Demand Multi-Node Charging Techniques for Wireless Sensor Networks
    (Elsevier, 2016-10-01) Khelladi, Lyes; Djenouri, Djamel; Rossi, Michele; Badache, Nadjib
    This paper deals with wireless charging in sensor networks and explores efficient policies to perform simultaneous multi-node power transfer through a mobile charger (MC).The proposed solution, called On-demand Multi-node Charging (OMC), features an original threshold-based tour launching (TTL) strategy, using request grouping, and a path planning algorithm based on minimizing the number of stopping points in the charging tour. Contrary to existing solutions, which focus on shortening the charging delays, OMC groups incoming charging requests and optimizes the charging tour and the mobile charger energy consumption. Although slightly increasing the waiting time before nodes are charged, this allows taking advantage of multiple simultaneous charges and also reduces node failures. At the tour planning level, a new modeling approach is used. It leverages simultaneous energy transfer to multiple nodes by maximizing the number of sensors that are charged at each stop. Given its NP-hardness, tour planning is approximated through a clique partitioning problem, which is solved using a lightweight heuristic approach. The proposed schemes are evaluated in offline and on-demand scenarios and compared against relevant state-of-the-art protocols. The results in the offline scenario show that the path planning strategy reduces the number of stops and the energy consumed by the mobile charger, compared to existing offline solutions. This is with further reduction in time complexity, due to the simple heuristics that are used. The results in the on-demand scenario confirm the effectiveness of the path planning strategy. More importantly, they show the impact of path planning, TTL and multi-node charging on the efficiency of handling the requests, in a way that reduces node failures and the mobile charger energy expenditure.
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    MSR : Minimum-Stop Recharging Scheme for Wireless Rechargeable Sensor Networks
    (CERIST, 2014-07-02) Khelladi, Lyes; Djenouri, Djamel; Badache, Nadjib; Bouabdallah, Abdelmadjid; Lasla, Noureddine
    This paper deals with simultaneous energy transfer to multiple nodes for scalable wireless recharging in wireless sensor networks. All existing recharging schemes rely on the use of a mobile charger that roves the network and drops by some locations for nodes recharging. However, they focus on the efficiency of energy transfer and neglect the energy engendered by the charger movement. This is tackled in this paper, where the wireless charging is modeled as a path optimization problem for the mobile charger, with objective function to minimizing the number of stop locations in the path. Due to the NP-harness of the problem, we propose a simple but efficient heuristic. It is based on clique partitioning to find the minimum number of locations allowing the mobile charger to replenish all the node’s batteries in the network. Evaluation results demonstrate that the proposed approach significantly reduces the total energy consumption of the mobile charger, while using a low-complexity techniques that permit scalability to a higher number of nodes.
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    Scalability of Wireless MAC Protocols in Mobile Ad hoc Networks
    (IEEE, 2005-07) Djenouri, Djamel; Bouznada, Mohamed; Khiyat, Faten; Khelladi, Lyes
    The rapid proliferation of lightweight wireless mobile devices, such as laptops, PDAs, and sensors makes mobile ad hoc networks (MANETs) an exciting and important research area nowadays. The MANET community have been concentrating on some problems related to the network layer, especially on the routing protocols. But regarding the MAC layer, little has been done. Our contri- bution in this paper is the deep investigation of the MAC protocols scalability in MANETs, using the GloMoSim simulation tool. We think we are the first who consider the scalability factor when analyzing MAC protocols in MANETs.
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    Security Issues of Mobile Ad hoc and Sensor Networks
    (IEEE Communications Society, 2005-12) Djenouri, Djamel; Khelladi, Lyes; Badache, Nadjib
    Security in mobile ad hoc networks is difficult to achieve, notably because of the vulnerability of wireless links, the limited physical protection of nodes, the dynamically changing topology, the absence of a certification authority, and the lack of a centralized monitoring or management point. Earlier studies on mobile ad hoc networks (MANETs) aimed at proposing protocols for some fundamental problems, such as routing, and tried to cope with the challenges imposed by the new environment. These protocols, however, fully trust all nodes and do not consider the security aspect. They are consequently vulnerable to attacks and misbehavior. More recent studies focused on security problems in MANETs, and proposed mechanisms to secure protocols and applications. This article surveys these studies. It presents and discusses several security problems along with the currently proposed solutions (as of July 2005) at different network layers of MANETs. Security issues involved in this article include routing and data forwarding, medium access, key management and intrusion detection systems (IDSs). This survey also includes an overview of security in a particular type of MANET, namely, wireless sensor networks (WSNs).