Youssef Fakhri

Energy-efficient MAC protocol based on IEEE 802.11e for Wireless Multimedia Sensor Networks

Energy consumption in wireless sensor networks (WSN) was always a basic constraint to respect. But, with the appearance of Wireless Multimedia Sensor Networks (WMSN), another basic constraint comes from added, which is the traffic performance in terms of delay, throughput, and Packet Delivery Rate (PDR). The choice of channel access method can help us to better respond the two constraints in WMSN. The Distributed Coordination Function (DCF) access method has been frequently used by WSN with different modifications to reduce energy consumption. But in the WMSN, we must take into consideration as well the traffic performance. Hence the idea to study the feasibility of using an access method of the IEEE 802.11e in WMSN. In this paper we will analyze energy consumption and evaluate the performance of the 802.11e Enhanced Distributed Channel Access (EDCA) with and without the mechanism Contention Free Burst (CFB), compared with IEEE 802.11 DCF. The results show that the use of EDCA CFB gives better performance, and offers a very good relationship between energy consumption and traffic performance, which is recommended in WMSN.

Lifetime maximisation algorithm in Wireless Sensor Network

In a Wireless Sensor Network (WSN), nodes are battery powered and then they are energy constrained. Network lifetime is the most important characteristics of performance for these networks. In this paper, we propose routing protocols that take into account the battery residual energy in sensor nodes and the energy required for transmission along the path toward the sink, which allows the distribution of energy load among the whole network nodes. Simulation results show that the network lifetimes increases up to 50% for the first node die and up to 114% for the last node die over comparable schemes like MLER protocol.

Impact of Mobility on Delay-Throughput Performance in Multi-Service Mobile Ad-Hoc Networks

Mobile Ad-Hoc network is a collection of mobile nodes in communication without using infrastructure. Despite the importance of type of the exchanged data between the knots on the QoS of the MANETs, the mul-tiservice data were not treated by the larger number of previous researches. In this paper we propose an adaptive method which gives the best performances in terms of delay and throughput. We have studied the impact, respectively, of mobility models and the density of nodes on the performances (End-to-End Delay, Throughput and Packet Delivery ratio) of routing protocol (On-Demand Distance Vector) AODV by using in the first a multiservice VBR (MPEG-4) and secondly the Constant Bit Rate (CBR) traffic. Finally we com-pare the performance on both cases. Experimentally, we considered the three mobility models as follows Random Waypoint, Random Direction and Mobgen Steady-State. The experimental results illustrate that the behavior of AODV change according to the model and the used traffics.

Evaluation of impact of traffic VBR and mobility on the performance of AODV routing protocols in mobile ad hoc networks

Mobile ad-hoc network (MANET) is a collection of intercommunicating mobile hosts that dynamically forming a spontaneous network without use existing infrastructure. The mobility model represents the moving behavior of each mobile node in the MANET that should be realistic. It is a crucial part in the performance evaluation of MANET. In this paper we propose a novel performance evaluation by using traffic VBR. The goal of our work is to study the impact of various random mobility models on the performance of On-Demand Distance Vector Routing (AODV) protocol. We have studied the impact of node density with two different values of pause time for a fixed speed on performance (End-to-End Delay, Throughput and Packet Delivery Ratio). For experimental purposes, we have considered three mobility models: Random Waypoint, Random Direction and Mobgen-Steady State. Experimental results illustrate that the performance of the routing protocol varies across different mobility models.

A Novel Energy Aware Clustering Technique for Routing in Wireless Sensor Networks

Cluster-based architectures are one of the most practical solutions in order to cope with the requirements of large-scale wireless sensor networks (WSN). Cluster-head election problem is one of the basic QoS requirements of WSNs, yet this problem has not been sufficiently explored in the context of cluster-based sensor networks. Specifically, it is not known how to select the best candidates for the cluster head roles. In this paper, we investigate the cluster head election problem, specifically concentrating on applications where the energy of full network is the main requirement, and we propose a new approach to exploit efficiently the network energy, by reducing the energy consumed for cluster forming.

A fairly balanced clustering algorithm for routing in wireless sensor networks

Purpose – Routing protocols in wireless sensor networks (WSN) are a crucial challenge for which the goal is maximizing the system lifetime. Since the sensor nodes are with limited capabilities, these routing protocols should be simple, scalable, energy‐efficient, and robust to deal with a very large number of nodes, and also self‐configurable to node failures and changes of the network topology dynamically. The purpose of this paper is to present a new algorithm for cluster forming in WSN based on the node energy required to transmit to the base station.Design/methodology/approach – Rotation selection of cluster‐head considering the remoteness of the nodes to the sink, and the network node residual energy.Findings – The simulation results show that this algorithm allows network stability extension compared to the most known clustering algorithm.Originality/value – Giving a probability to become cluster‐head based on the remoteness of the node to the sink.

Lifetime optimization for Wireless Sensor Networks

In a Wireless Sensor Network (WSN), nodes are battery powered, therefore, there are energy constrained. Network lifetime is one of the most important characteristics of performance for wireless sensor networks. A number of routing schemes, energy efficient and energy-aware, have been proposed to maximize the network lifetime. These schemes typically try to find the minimum energy path to optimize energy usage at a node. In this paper, we consider the lifetime maximization problem, we propose a routing protocols that take into account the battery residual energy in sensor nodes and the energy required for transmission along the path 1. For each transmission round, only the nodes which have their remaining energies greater than a threshold can participate as relays for other nodes data in addition to sensing the environment. This choice allows the distribution of energy load among any sensor nodes, thus extends network lifetime. Simulation results show that the network lifetimes is increased largely comparable to Direct and MTE schemes.

Energy consumption analysis and modelling of a H.264/AVC intra-only based encoder dedicated to WVSNs

This paper proposes a model to predict the energy consumption of a H.264/AVC intra-only based encoder designed for the wireless video sensor networks (WVSNs). Such model is of great interest in an energy-constrained context like the WVSN, where the video streams are processed prior to transmission. In fact, accounting for both processings and transmissions consumed energies allows the optimization of the global energy consumption. The proposed model predicts the processings energy consumption based on the considered Quantization Parameter (QP) and the Frame Rate (FR) values. The generic form of this model enables it to predict the energy consumption of any H.264/AVC intra-only based encoder. Simulation results demonstrate the accuracy of the proposed model, that is validated under different resolutions, QP and FR, with an average prediction error of 4%.

Increasing network lifetime in an energy-constrained wireless sensor network

Energy in wireless sensor networks is a scarce resource, therefore an energy-efficient mechanism is required to increase the network lifetime. In this paper, we study the problem of optimal power allocation, taking into account the estimation of the total signal-to-noise ratio at the fusion centre FC. We consider that nodes transmit their data to the fusion centre over quasi-static Rayleigh fading channels. In order to analyse our approach, we first investigate the orthogonal channel case and then the non-orthogonal one introducing a virtual MISO framework communication scheme. We consider in both cases that the nodes have channel state information. Simulations show that the new algorithm introduced provides a network extension lifetime of more than 80% in comparison with other traditional methods.

Contention Window MAC parameters tyning for wireless multimedia Sensor Networks

The strong constraint of the traffic performance (Delay, Throughput, etc.) of Wireless Multimedia Sensor Networks (WMSN) is a great challenge to satisfy. For this reason, an enhanced version of the access method IEEE 802.11e Enhanced Distributed Channel Access (EDCA) with the duty cycling mechanism has been used in the MAC layer of the WMSN. The EDCA maintains four Access Categories (AC) representing four levels of priority. The priority of each AC is maintained by a set of MAC parameters. In this paper, we will study the influence of the MAC parameters Contention Window CWmin and CWmax of the EDCA on the energy consumption and the traffic performance of the WMSN. The simulation results show the clear existence of influence. In addition, we noticed that the dynamic adaptation of these two parameters will enable efficient adaptation and use of the EDCA in the WMSN in terms of energy consumption and traffic performance.