International Conference Papers

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Subject: search.filters.subject.Wireless sensor networks

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    Congestion Detection Strategies in Wireless Sensor Networks: A Comparative Study with Testbed Experiments
    (Elsevier, 2014-09) Kafi, Mohamed Amine; Djenouri, Djamel; Ouadjaout, Abdelraouf; Badache, Nadjib
    Event based applications of Wireless Sensor Networks (WSNs) are prone to traffic congestion, where unpredicted event detection yields simultaneous generation of traffic at spatially co-related nodes, and its propagation towards the sink. This results in loss of information and waste energy. Early congestion detection is thus of high importance in such WSN applications to avoid the propagation of such a problem and to reduce its consequences. Different detection metrics are used in the congestion control literature. However, a comparative study that investigates the different metrics in real sensor motes environment is missing. This paper focuses on this issue and compares some detection metrics in a testbed network with MICAz motes. Results show the effectiveness of each method in different scenarios and concludes that the combination of buffer length and channel load constitute the better candidate for early and fictive detection.
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    Interference-aware Congestion Control Protocol for Wireless Sensor Networks
    (Elsevier, 2014-09) Kafi, Mohamed Amine; Djenouri, Djamel; Ben Othman, Jalel; Ouadjaout, Abdelraouf; Bagaa, Miloud; Lasla, Noureddine; Badache, Nadjib
    This paper deals with congestion and interference control in wireless sensor networks (WSN), which is essential for improving the throughput and saving the scarce energy in networks where nodes have different capacities and traffic patterns. A scheme called IACC (Interference-Aware Congestion Control) is proposed. It allows maximizing link capacity utilization for each node by controlling congestion and interference. This is achieved through fair maximum rate control of interfering nodes in inter and intra paths of hot spots. The proposed protocol has been evaluated by simulation, where the results rival the effectiveness of our scheme in terms of energy saving and throughput. In particular, the results demonstrate the protocol scalability and considerable reduction of packet loss that allow to achieve as high packet delivery ratio as 80% for large networks.
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    Improved coverage through area-based localization in wireless sensor networks
    (IEEE, 2013-10) Lasla, Noureddine; Younis, Mohamed; Badache, Nadjib
    Ensuring area coverage is one of the key requirements of wireless sensor networks (WSNs). When nodes are randomly placed in the area of interest, redundancy is often provisioned in order to lower the probability of having voids, where part of the area is not within the detection range of any sensor. To extend the lifetime of the network, a duty cycle mechanism is often applied in which only a subset of the nodes are activated at a certain time while the other nodes switch to low-power mode. The set of active nodes are changed over time in order to balance the load on the individual sensors. The selection of active nodes is subject to meeting the coverage requirement. Assessing the coverage of a sensor is based on knowing its position. However, localization schemes usually yield a margin of errors which diminishes the coverage fidelity. Conservative approaches for mitigating the position inaccuracy assume the worst-case error across the network and end up activating excessive number of nodes and reduces the network lifetime. In this paper, we present an approach for estimating a bound on the maximum error for the position of each sensor and propose a distributed algorithm for achieving high fidelity coverage while engaging only a subset of the sensors. The simulation results confirm the performance advantages of our approach.
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    Congestion Detection Strategies in Wireless Sensor Networks: A Comparative Study with Testbed Experiments
    (Elsevier, 2014) Kafi, Mohamed Amine; Djenouri, Djamel; Ben Othman, Jalel; Ouadjaout, Abdelraouf; Badache, Nadjib
    Event based applications of Wireless Sensor Networks (WSNs) are prone to traffic congestion, where unpredicted event detection yields simultaneous generation of traffic at spatially co-related nodes, and its propagation towards the sink. This results in loss of information and waste energy. Early congestion detection is thus of high importance in such WSN applications to avoid the propagation of such a problem and to reduce its consequences. Different detection metrics are used in the congestion control literature. However, a comparative study that investigates the different metrics in real sensor motes environment is missing. This paper focuses on this issue and compares some detection metrics in a testbed network with MICAz motes. Results show the effectiveness of each method in different scenarios and concludes that the combination of buffer length and channel load constitute the better candidate for early and fictive detection.
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    DZ50: Energy-efficient Wireless Sensor Mote Platform for Low Data Rate Applications
    (Elsevier, 2014) Ouadjaout, Abdelraouf; Lasla, Noureddine; Bagaa, Miloud; Doudou, Messaoud; Zizoua, Cherif; Kafi, Mohamed Amine; Derhab, Abdelouahid; Djenouri, Djamel; Badache, Nadjib
    A low cost and energy e_cient wireless sensor mote platform for low data rate monitoring applications is presented. The new platform, named DZ50, is based on the ATmega328P micro-controller and the RFM12b transceiver, which consume very low energy in low-power mode. Considerable energy saving can be achieved by reducing the power consumption during inactive (sleep) mode, notably in low data rate applications featured by long inactive periods. Without loss of generality, spot monitoring in a Smart Parking System (SPS) and soil moisture in a Precision Irrigation System (PIS) are selected as typical representative of low data rate applications. The performance of the new platform is investigated for typical scenarios of the selected applications and compared with that of MicaZ and TelosB. Energy measurements have been carried out for di_erent network operation states and settings, where the results reveal that the proposed platform allows to multiply the battery lifetime up to 7 times compared to MicaZ and TelosB motes in 10s sampling period scenarios.
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    New QoS and Geographical Routing in Wireless Biomedical Sensor Networks
    (IEEE, 2009-09) Djenouri, Djamel; Balasingham, Ilangko
    In this paper we deal with biomedical applications of wireless sensor networks, and propose a new quality of service (QoS) routing protocol. The protocol design relies on traffic diversity of these applications and ensures a differentiation routing using QoS metrics. It is based on modular and scalable approach, where the protocol operates in a distributed, localized, computation and memory efficient way. The data traffic is classified into several categories according to the required QoS metrics, where different routing metrics and techniques are accordingly suggested for each category. The protocol attempts for each packet to fulfill the required QoS metrics in a power-aware way, by locally selecting the best candidate. It employs memory and computation efficient estimators, and uses a multi-sink single-path approach to increase reliability. The main contribution of this paper is data traffic based QoS with regard to all the considered QoS metrics. To our best knowledge, this protocol is the first that makes use of the diversity in the data traffic while considering latency, reliability residual energy in the sensor nodes, and transmission power between sensor nodes as QoS metrics of the multi-objective problem. The proposed algorithm can operate with any MAC protocol, provided that it employs an ACK mechanism. Performance evaluation through a simulation study, comparing the new protocol with state-of-the QoS and localized protocols, show that it outperforms all the compared protocols.
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    Brief Announcement on MOGRIBA: Multi-Objective Geographical Routing for Biomedical Applications of Wireless Sensor Networks
    (LNCS, 2009-07) Djenouri, Djamel; Balasingham, Ilangko
    A new routing protocol for wireless sensor networks is proposed in this paper. The proposed protocol focuses on medical applications, by considering its traffic diversity and providing a differentiation routing using quality of service (QoS) metrics. The design is based on modular and scalable approach, where the protocol operates in a distributed, localized, computation and memory efficient way. The main contribution of this paper is data traffic based QoS with regard to all the considered QoS metrics, notably reliability, latency, and energy. To our best knowledge, this protocol is the first that makes use of the diversity in the data traffic while considering latency, reliability, residual energy in the sensor nodes, and transmission power between sensor nodes as QoS metrics of the multi-objective problem. Simulation study comparing the protocol with state-of-the QoS and geographical routing protocols shows that it outperforms all the compared protocols.
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    LOCALMOR: LOCALized Multi-Objective Routing for Wireless Sensor Networks
    (IEEE, 2009-09) Djenouri, Djamel; Balasingham, Ilangko
    This paper proposes a multi-objective quality of service (QoS) routing protocol for wireless sensor networks (WSN). The protocol takes into account the traffic diversity typical for many applications and provides a differentiation in routing using QoS metrics. It ensures several QoS metrics for different traffic categories, and attempts for each packet to fulfill the required metrics in a power-aware and localized way. It employs memory and computation efficient estimators in a distributed manner and uses a multi-sink single-path approach to increase reliability. The main contribution of this paper is data traffic based QoS with regard to all the considered QoS metrics. As far as we know, this protocol is the first that makes use of the diversity in the data traffic while considering latency, reliability, residual energy in the sensor nodes, and transmission power between nodes and casts QoS metrics as a multi-objective problem. The proposed algorithm can operate with any MAC protocol, provided that it employs an ACK mechanism. Simulation results show the proposed protocol outperforms all compared state-of-the-art QoS and localized routing protocols.
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    Power-Aware QoS Geographical Routing for Wireless Sensor Networks - Implementation using Contiki
    (IEEE, 2010-06) Djenouri, Djamel; Balasingham, Ilangko
    This paper presents the design and implementation of a new geographical quality of service (QoS) routing for wireless sensor networks. The protocol is based on traffic differentiation and provides customized QoS according to the traffic requirement. For each packet, the protocol attempts to fulfill the required data-related QoS metric(s) while considering power-efficiency. The data related metrics include packet latency and reliability, while power-efficiency has been considered for both power transmission minimization and residual energy maximization (load balancing). The protocol has been implemented in real sensor motes using Contiki operating system, which offers many modules and has many features that facilitate efficient communication protocol implementation. The protocol was then evaluated in a testbed. The experimental results show good QoS performance, and particularly, traffic-differentiation QoS as expected, i.e., QoS-sensitive packets were routed with better performances than regular packets. The protocol is generic and applies to any application with traffic requiring different QoS, such as in biomedical and vehicular applications.
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    Distributed Receiver/Receiver Synchronization in Wireless Sensor Networks: New Solution and Joint Offset/Skew Estimators for Gaussian Delays
    (Spinger, 2011-08) Djenouri, Djamel
    This paper proposes a new synchronization protocol for wireless sensor networks (WSN). The proposed protocols is based on the receive/reieve approach, which was introduced by the Reference Broadcast Synchronization (RBS). This approach has been chosen for its lower time-critical path compared to the sender/receiver approach. Contrary to RBS upon which rely all current receiver/receiver solutions, the proposed one is totally distributed and does not depend on any fixed reference. The reference’s function is balanced among all sensors, which eliminates the single point of failure shortcomings. RBS needs additional steps for exchanging reception timestamps. On the other hand, the proposed protocol allow these timestamps to be piggybacked to the regular beacons, reducing thus the overhead and energy consumption. The protocol deals with local synchronization and allows neighboring nodes to relatively synchronize with each other by estimating relative skews/offsets. Maximum Likelihood estimators (MLEs) are derived for channels with Gaussian (normal) distributed delays, and for both offset-only and joint offset/skew models. The Cramer-Rao Lower Bounds (CRLBs) are derived for each model and numerically compared with the MLE. Results show quick convergence of the proposed estimators’ precision to CRLB. To our knowledge, this is the first distributed receiver/receiver solution that eliminates the need of a fixed reference while taking advantage of the receiver/receiver synchronization’s precision.