Aawatif Hayar

Spectrum sensing for cognitive radio exploiting spectrum discontinuities detection

This article presents a spectrum sensing algorithm for wideband cognitive radio exploiting sensed spectrum discontinuity properties. Some work has already been investigated by wavelet approach by Giannakis et al., but in this article we investigate an algebraic framework in order to model spectrum discontinuities. The information derived at the level of these irregularities will be exploited in order to derive a spectrum sensing algorithm. The numerical simulation show satisfying results in terms of detection performance and receiver operating characteristics curves as the detector takes into account noise annihilation in its inner structure.

A Complete Framework for Spectrum Sensing Based on Spectrum Change Points Detection for Wideband Signals

This paper presents a novel technique in spectrum sensing based on a new characterization of primary users signals in wideband communications. First, we have to remind that in cognitive radio networks, the very first task to be operated by a cognitive radio is sensing and identification of spectrum holes in the wireless environment. This paper summarizes the advances in the algebraic approach. Initial results have been already disseminated in few other conferences. This paper aims at finalizing and presenting the last results and the complete framework of the proposed technique based on algebraic spectrum discontinuities detection. The signal spectrum over a wide frequency band is decomposed into elementary building blocks of subbands that are well characterized by local irregularities in frequency. As a powerful mathematical tool for analyzing singularities and edges, the algebraic framework is employed to detect and estimate the local spectral irregular structure, which carries important information on the frequency locations and power spectral densities of the sensed subbands. In this context, a wideband spectrum sensing techniques was developed based on an analog decision function to multi-scale wavelet product. The proposed sensing techniques provide an effective sensing framework to identify and locate spectrum holes in the signal spectrum.

Game theory-based resource management strategy for cognitive radio networks

This paper investigates the application of game theory tools in the context of cognitive radio networks (CRN). Specifically, we propose a resource management strategy with the objective to maximize a defined utility function subject to minimize the mutual interference caused by secondary users (SUs) with protection for primary users (PUs). In fact, we formulate a utility function to reflect the needs of PUs by verifying the outage probability constraint, and the per-user capacity by satisfying the signal-to-noise and interference ratio (SNIR) constraint, as well as to limit interference to PUs. Furthermore, the existence of the Nash equilibrium of the proposed game is established, as well as its uniqueness under some sufficient conditions. Theoretical and simulation results based on a realistic network setting, and a comparison with a previously published resource management method are provided in this paper. The reported results demonstrate the efficiency of the proposed technique in terms of CRN deployment while maintaining quality-of-service (QoS) for the primary system.

Secure HeNB network management based VPN IPSec

Femtocells are small base stations used inside buildings to improve radio coverage (Indoor). In this paper we present an overview of femtocells, focusing more particularly our research topic on the congestion, power and security management of HeNB (Home eNodeB). We also propose new architecture for managing in a secure way femtocells network using VPN IPSec.

New renewable energy allocation algorithms based on bin packing in a smart home

More and more home owners fit their homes with renewable energy sources. Thus, to capitalize this, they are willing to install intelligent energy management systems to try to reduce their energy bills, which requires optimal use of energy. To deal with this, this paper presents two energy management algorithms, all based on the principle of the bin packing problem. The proposed solutions are built on prioritizing the use of renewable energy produced locally over energy provided by the main grid. A well detailed simulation was carried out to highlight the contribution of the implementation of this solution in a smart home located in Casablanca, Morocco, whose energy needs are from a daily approximation of the habits of the city residents. Moreover, a comparison between the two algorithms was made to showcase the benefits of each, and their difference.

Channel division multiple access: The access solution for UWB networks

In this paper we study a promising multiple access scheme entitled Channel Division Multiple Access (ChDMA). ChDMA was developed to cope with the particularities of low duty cycle Impulsive Radio Ultra Wideband systems (IR-UWB). The idea is based upon the fact that Channel Impulse Responses (CIR) could be exploited as users signatures. Based on the knowledge of the CIRs at the receiver, transmitted signals can be detected and estimated in a very similar approach as performed by DS-CDMA systems. We present in this contribution initial analysis of the spectral efficiency performance of ChDMA systems. As a matter of fact, ChDMA overcomes the multiple access paradigm of impulsive-radio signaling and provides an efficient and low complex technique to exploit the diversity of UWB communications. For the study, we consider three different receiver structures: optimal receiver, matched filter (MF) and linear minimum mean square error receiver (l-MMSE). As a result, it is shown that under certain conditions ChDMA can even outperform CDMA in terms of Shannons capacity, providing a real option for future communication systems.

Power management for collaborative microgrids

Microgrids integrating green energy receive more attention from consumers since they present significant benefits including the ability to rely on more localized sources of power generation and keeping the environment healthy and safe. Thus, neighborhoods/cities opt for providing energy from green resources. However, the integration of renewable energies could lead to certain problems such as the destabilization and destruction of the power grids. For this reason, it is essential to build a robust management system and efficient communication between microgrids devices. This paper proposes a new approach based on a dynamic assignment of renewable energy tokens (DARET) algorithm and investigates a non-uniform hierarchical modulation as a data transmission technique over wireless channels. The proposed algorithm allows residential microgrids of a small geographic area to dynamically collaborate and share their individual green energy generation in order to supply their overall loads. The sharing is dynamically updated in short-term by exchanging data, in terms of individual demands and supplies, between the consumers over wireless links.

A New ICT-based Modeling for the Power Grid.

The purpose of this work is to propose a new theoretical and mathematical model that describes the energy flow over a microgrid, à small portion of a power grid. Indeed, there is similarity between a transmission channel made up of several transmitters/receivers and the microgrid involving various energy sources/consumers. This has been the premise which prompt us to conduct this study and develop a new model of the microgrid. The propounded model is not to contest or to interrogate electromechanical results about the flow of electricity. It rather brings another way of seeing the energy flow. Moreover, this framework bears in mind intermittent energy sources. The inclusion of renewable energy sources in the conventional power grid has to be taken into account in order to come up with a model that is faithful to the current state of the grid. On the basis of a MIMO (multiple-input and multiple-output) channel, the proposed architecture consists of a Single Virtual Power Source (SVPS) serving its energy at several energy consumption points. Its energy flow’s shape is a Gaussian as it will be demonstrated throughout this paper.

Proposed Model of Street Lighting System based on OFDM Operations for Smart Lighting.

Abandoned for a very long time, because of the complexity of their Multi-Carrier techniques (Multi Carrier Modulation, MCM or Orthogonal Frequency Division Multiplexing OFDM), nowadays, the OFDM has become the strategic choice of several systems modern digital products. Its simplicity and flexibility, as well as the transmission, make them particularly interesting for communication systems. Inspired from Telecommunications field, especially from the OFDM Techniques, the aim of this paper, is to propose a model of street lighting system based on OFDM operations, this technique is used here control and to switch On/Off the street lamps and to launch a proposed waveform of voltage command of lighting when pedestrian or vehicle detections are occurred, even in cases of multi detections in streets or in other words branches of street lamps. This proposed model will allow us to illuminate intelligently by using a new strategy of voltage command of lighting and to reduce considerably the rate of power consumption during the lighting for smart lighting and so, contributing on having a smart city.

Public street-lamps autonomy increasing based on self-lighting concept

This paper presents a new proposed idea in photovoltaic cell modelling, which consists on exposing a solar panel to its own light source during the night in order to increase its autonomy. This study is based on mathematical equations, its also described through a new equivalent circuit including a photocurrent source Iph and Iec, a diode, a series and shunt resistors. Indeed, this paper describes also all experiments we did in the laboratory and all the results we had in order to evaluate more the efficiency of the new proposed modelling, the goal is to see how much an auxiliary source lighting can extend the discharge duration of the battery which results more autonomy. This new idea proposed will optimize the energy used in solar public street lighting with a gain of up to two hours.