Rachid Saadane

Developed Distributed Energy-Efficient Clustering (DDEEC) for heterogeneous wireless sensor networks

Typically, a wireless sensor network contains an important number of inexpensive power constrained sensors, which collect data from the environment and transmit them towards the base station in a cooperative way. Saving energy and therefore, extending the wireless sensor networks lifetime, imposes a great challenge. Clustering techniques are largely used for these purposes. In this paper, we propose and evaluate a clustering technique called a Developed Distributed Energy-Efficient Clustering scheme for heterogeneous wireless sensor networks. This technique is based on changing dynamically and with more efficiency the cluster head election probability. Simulation results show that our protocol performs better than the Stable Election Protocol (SEP) by about 30% and than the Distributed Energy-Efficient Clustering (DEEC) by about 15% in terms of network lifetime and first node dies.

Subspace analysis of indoor UWB channels

This work aims at characterizing the second-order statistics of indoor ultra-wideband (UWB) channels using channel sounding techniques. We present measurement results for different scenarios conducted in a laboratory setting at Institut Eurécom. These are based on an eigendecomposition of the channel autocovariance matrix, which allows for the analysis of the growth in the number of significant degrees of freedom of the channel process as a function of the signaling bandwidth as well as the statistical correlation between different propagation paths. We show empirical eigenvalue distributions as a function of the signal bandwidth for both line-of-sight and non-line-of-sight situations. Furthermore, we give examples where paths from different propagation clusters (possibly arising from reflection or diffraction) show strong statistical dependence.

Stochastic and Equitable Distributed Energy-Efficient Clustering (SEDEEC) for heterogeneous wireless sensor networks

The hierarchical clustering technique reduces strongly direct transmissions which consumes hardly the nodes energy. Many new protocols are specifically designed for wireless sensor networks using this strategy, where the objectives are to save energy and extend the networks lifetime. Adapting this approach, we propose a more equitable and stochastic technique which distributes uniformly the energy consumed trough the whole network using a dynamic probability to elect the Cluster Head (CH). This protocol is used for more energy efficiency distribution where the BS is localised far away from the network. Moreover, it is used where the collect data defines the maximum or the minimum values in supervised region. Simulation results show that our protocol enlarges the network lifetime and performances results compared to the Low-Energy Adaptive Clustering Hierarchy (LEACH), the Distributed Energy-Efficient Clustering (DEEC) and the Equitable Distributed Energy-Efficient Clustering (EDEEC).

Clustering in Wireless Sensor Networks based on near optimal bi-partitions

Wireless Sensor Networks (WSNs) have recently become an area of attractive research interest. A WSN consists of low-cost, low power, and energy-constrained sensors responsible for monitoring and reporting a physical phenomenon to the sink node where the end-user can access the data. Reducing energy consumption and enlarging lifetime of the whole WSNs are the important challenges in these fields of applications. To deal with these challenges, clustering algorithms can be used. In this paper we present a new approach called the Spectral Classification based on Near Optimal Clustering in Wireless Sensor Networks (SCNOpC-WSNs). This protocol uses spectral graph theory in order to subdivide the network such that each cluster includes the highest inter-correlated sensors. Simulation results demonstrate that SCNOpC-WSNs distribute energy consumption more effectively among the sensors. Thus, the proposed approach enlarges the network lifetime by as much as 44.8% compared to LEACH.

A new spectral classification for robust clustering in wireless sensor networks

Wireless sensor network has recently become an area of attractive research interest. It consists of low-cost, low power, and energy-constrained sensors responsible for monitoring a physical phenomenon and reporting to sink node where the end-user can access the data. Saving energy and therefore extending the wireless sensor network lifetime, involves great challenges. For these purposes, clustering techniques are largely used. Using many empirical successes of spectral clustering methods, we propose a new algorithm that we called Spectral Classification for Robust Clustering in Wireless Sensor Networks (SCRC-WSN). This protocol is a spectral partitioning method using graph theory technics with the aim to separate the network in a fixed optimal number of clusters. The clusters nodes communicate with an elected node called cluster head, and then the cluster heads communicate the information to the base station. Defining the optimal number of clusters and changing dynamically the cluster head election probability are the SCRC-WSN strongest characteristics. In addition our proposed protocol is a centralized one witch take into account the nodes residual energy to define the cluster heads. We studied the impact of node density on the robustness of the SCRC-WSN algorithm as well as its energy and its lifetime gains. Simulation results show that the proposed algorithm increases the lifetime of a whole network and presents more energy efficiency distribution compared to the Low-Energy Adaptive Clustering Hierarchy (LEACH) approach and the Centralized LEACH (LEACH-C)one.

Ultra wide bandwidth radio channel indoor propagation and path loss analysis based on measurements

In this paper, based on a set of UWB Channel measurements some features of channel are investigated. The measurements are provided in frequency domain over a channel bandwidth 6 GHz (from 3 to 9 GHz) in indoor, at Eurecom Institute. A Vector Network Analyzer is used to measure the frequency channel response of the frequency bandwidth of interest. An Omni-directional antennas are used for both the transmitter and receiver antennas. Probability Density Function (PDF) and Cumulative Distribution Function (CDF) of received signal, power variation and path loss fluctuations are evaluated in frequency domain. An investigation of path loss shows no dependency between frequency and the path loss. Other features of this approach also are outlined.

Spectrum sensing with an improved Energy detection

Opportunistic spectrum access is a critical application in the context of cognitive radio, and knowing that the detection of free bands in the spectrum is the key to such application. It has shown that the detection of energy is the most convenient method, in the sense that there is no a priori information about the primary user. In this work, The implementation of the energy detection technique has been done in MatLab for both models, AWGN and Rayleigh channels. The simulation confirmed the theoretical results, which gives that the error level in AWGN channel is less than a Rayleigh channel, and it is also verified that the performance of the detector is independent of the type of modulation. As the threshold used in this method depends on the environmental noise, we propose in this paper dynamic threshold selection to increase the probability of detection.

New High-Rate UWB Scheme for WBAN-Based Healthcare Systems

Given the emphasis on increasing wireless network usage for healthcare application, e.g., Wireless Body Area Network (WBAN), the need for high-rate physical layer has become a genuine concern from research and industrial community. The use of the Ultra-Wideband (UWB) is looking especially bright for such systems given its lower energy consumption and performances towards frequency-selective channels. However, the Multi-Band-OFDM-based UWB technique has some inherent limitations as loss in spectral e-ciency due to the use of Cyclic-Preflx (CP). In this paper, a new physical layer scheme for high-rate wireless body area networks based on MB-OFDM with Ofiset Quadrature Amplitude Modulation (OQAM) modulation is presented. The proposed MB-OFDM/OQAM can achieve high spectral and power e-ciency than conventional MB-OFDM system. Moreover, the use of the CP Interval in the conventional MBOFDM removes e-ciently the Inter-Symbols Interferences (ISI) but remains inefiective towards the Inter-Carriers Interferences (ICI) caused by the channel frequency ofiset (FO). The performances evaluation of the proposed technique will be carried-out in realistic UWB-WBANs channels with various scenarios, which will be also presented and studied herein.

Cooperation based Instantly Decodable Network Coding for mobile clouds

Cloud computing Concept has been recognized as the next generation computing infrastructure. In addition, the explosive expansion of mobile devices usage around all over the world leads to more requirements in terms of resources, environment, and security. Therefore, mobile cloud computing (MCC) paradigm emerges, and it is considered as the future technology for mobile services and applications. Furthermore, Network Coding (NC) is a novel technique that aims to improve performance and throughput in wireless communication. Our works concern is to build a delay and throughput optimized network coding scheme with mobile cooperation for broadcast based Mobile clouds applications. Hence, after a deep literature study, we proposed a scheme that introduces the use of cooperation with Instantly Decodable Network Coding. In order to evaluate our proposition, we carried out simulation experiments to test it and compare it with relevant existing solutions. Finally, the results are very encouraging and the proposed scheme gives a satisfactory delay compared to the existing solutions.

A Survey of Handovers Decision Algorithms for Next Generation Wireless Networks

3 Abstract: With technological advances in the telecommunications sector, everyone around the world would like to be connected seamlessly anytime anywhere through the best network. Making a transition from one network to another and moving between heterogeneous networks is not the only problem that worried specialists, scientific and mobile operators; the concern of QoS is as important as the handoff, The requirements like capability of the network, network conditions, handoff latency, power consumption, network cost, and user preferences must be taken into consideration during vertical handoff. Importance of inter working between architecture requires adaptive approaches to implement the vertical handoff mechanism in 4G wireless networks and produce an effective service for the user by considering handover parameters. In this paper, we analyzed the main approaches for vertical handoff to offer a systematic comparison for new researchers. The survey revealed the need for new approach which satisfy the most important requirements and reduce the HO failure probability and the number of unnecessary handover.