Research Reports

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Start date: 2010Subject: search.filters.subject.Wireless sensor networks

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Now showing 1 - 6 of 6
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    Interference-Aware Congestion Control Protocol for Wireless Sensor Networks
    (CERIST, 2014-07-07) 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 di erent capacities and tra c 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 e ectiveness 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 allows to achieve as high packet delivery ratio as 80% for large networks.
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    Congestion Detection Strategies in Wireless sensor Networks: A Comparative Study with Testbed Experiments
    (CERIST, 2014-07-07) Kafi, Mohamed Amine; Djenouri, Djamel; Ben Othman, Jalel; Ouadjaout, Abdelraouf; Badache, Nadjib
    Event based applications of Wireless Sensor Networks (WSNs) are prone to tra c congestion, where unpredicted event detection yields simultaneous generation of tra c 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. Di erent detection metrics are used in the congestion control literature. However, a comparative study that investigates the di erent 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 e ectiveness of each method in di erent scenarios and concludes that the combination of bu er length and channel load constitute the better candidate for early and fictive detection.
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    Point In half symmetric LEns : A new range-free localization protocol for wireless sensor networks
    (CERIST, 2011-02) Lasla, Noureddine; Derhab, Abdelouahid; Ouadjaout, Abdelraouf; Bagaa, Miloud; Badache, Nadjib
    As location information is used by many sensor network applications, localization is considered a keystone in their design. Existing localization protocols can be classi ed as range-based or range-free approaches. Range- based approaches are costly as they require embedding each sensor node with an additional hardware to estimate inter-node distances. In contrast, the range-free approaches are cheaper, and they estimate node position by collecting information from some special nodes with known location called anchors. Thus, compared with range- based approaches, the range-free ones are more suitable for WSNs. In this paper, we propose PIV (Point In half Vesica-piscis), a new distributed range-free localization protocol for wireless sensor networks. PIV is designed based on the geometric concept of Vesica-piscis, which helps to relax some unrealistic assumptions and incur the lower cost. Complexity analysis and simulations results show that PIV has the lowest message cost among the existing localization schemes and o ers the best trade-o between location accuracy and ratio of localized nodes.
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    Power-aware QoS Geographical Routing for Wireless Sensor Networks - Implementation using Contiki
    (CERIST, 2010-05) Djenouri, Djamel
    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 tra±c di®erentiation and provides customized QoS accord- ing to the tra±c requirement. For each packet, the protocol attempts to ful¯ll the required data-related QoS metric(s) while considering power-e±ciency. The data related metrics include packet latency and reliability, while power-e±ciency has been considered for both power transmission minimization and residual energy max- imization (load balancing). The protocol has been implemented in real sensor motes using Contiki operating system, which o®ers many modules and has many features that facilitate e±cient communication protocol implementation. The protocol was then evaluated in a testbed. The experimental results show good QoS performance, and particularly, tra±c-di®erentiation 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 tra±c requiring di®erent QoS, such as in biomedical and vehicular applications.
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    Theoretical Estimators and Lower-Bounds for Receiver-to-Receiver Time Synchronization in Multi-Hop Wireless Networks
    (CERIST, 2012) Djenouri, Djamel
    Maximum likelihood estimators (MLE) for time synchronization parameters of receiver-toreceiver protocols are derived. The MLE are first provided for a single-hop model, then generalized to a multi-hop model. The appropriate Cramer-Rao lower bounds (CRLB) for the estimators are then derived, which serves as a theoretical lower bound to any unbiased estimator. The proposed estimators are compared with their respective CRLB through simulation in multi-hop scenarios of up-to eight hops. The results show fast convergence of the estimation precision to the CRLB and demonstrate a high precision, where the mean square error (MSE) does not exceed 10
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    Cluster-Based Fast Broadcast in Duty-Cycled Wireless Sensor Networks
    (CERIST, 2012) Djenouri, Djamel; Khiati, Mustapha
    This paper proposes a cluster-based broadcast protocol to disseminate delay-sensitive information throughout a wireless sensor network. The protocol considers the use of duty-cycling at the MAC layer, which is essential to reduce energy dissipation. LEACH’s energy-efficiency approach is used for cluster construction. This approach shifts the total burden of energy consumption of a single cluster-head by rotating the cluster-head function among all nodes in the network. It also permits to switch the ordinary (member) nodes in a cluster into the sleep mode whenever they enter inactive TDMA slots. However, LEACH does not consider broadcast messages, and the member nodes scheduling is established as a sequence of TDMA without any common active period. A broadcast message should then be postponed to next TDMA schedule and transmitted a sequence of unicasts, which is inefficient in terms of latency, bandwidth occupation, and power consumption. The proposed protocol adds new common static and dynamic broadcast periods to support and accelerate broadcasting. The dynamic periods are scheduled following the past arrivals of messages, and using a Markov-chain model. To our knowledge, this work is the first that proposes the use of clustering to reduce broadcast latency. Taking advantage of LEACH’s clustering mechanism allow for simultaneous local broadcasts at several clusters in the WSN, and it also ensures scalability with the increase of the network size. This parallelism minimizes the end to-end broadcast latency compared to the current flat-topology solutions, where the end-to-end broadcast latency and the number of messages required to make a broadcast (message-count) are proportional to the network size. The protocol has been simulated, numerically analyzed, and compared with LEACH. The results show clear improvement over LEACH with regard to the latency, at a low energy cost.