Jean Michel Rouvaen

Multi-User Ultra-Wide Band Communication System Based on Modified Gegenbauer and Hermite Functions

In this paper a multi-user communication system based on ultra-wide band (UWB) technology is studied. UWB uses very short pulses, so that the spectrum of the emitted signals may spread over several GHz. In order to implement multi-user communication, the emitted signal must be modulated. One modulation scheme for UWB communications is to use analog waveforms to modulate the data.In this study, orthogonal waveforms called modified Gegenbauer functions are introduced as basis functions for the pulse shape and compared to the previously proposed modified Hermite functions. It is shown that Gegenbauer functions offer better performance for multi-user UWB communications.

An efficient speech recognition system in adverse conditions using the nonparametric regression

General Regression Neural Networks (GRNN) have been applied to phoneme identification and isolated word recognition in clean speech. In this paper, the authors extended this approach to Arabic spoken word recognition in adverse conditions. In fact, noise robustness is one of the most challenging problems in Automatic Speech Recognition (ASR) and most of the existing recognition methods, which have shown to be highly efficient under noise-free conditions, fail drastically in noisy environments. The proposed system was tested for Arabic digit recognition at different Signal-to-Noise Ratio (SNR) levels and under four noisy conditions: multispeakers babble background, car production hall (factory), military vehicle (leopard tank) and fighter jet cockpit (buccaneer) issued from NOISEX-92 database. The proposed scheme was successfully compared to the similar recognizers based on the Multilayer Perceptrons (MLP), the Elman Recurrent Neural Network (RNN) and the discrete Hidden Markov Model (HMM). The experimental results showed that the use of nonparametric regression with an appropriate smoothing factor (spread) improved the generalization power of the neural network and the global performance of the speech recognizer in noisy environments.

Minimizing energy consumption within wireless sensors networks using optimal transmission range between nodes

Recent advances in wireless communications and electronics have enabled the development of low-power and energy consumption, multifunctional sensor nodes that are small in size and communicate in short distances. These tiny sensor nodes, which consist of sensing and data processing, leverage the idea of sensor networks. Sensor size represents a significant limitation mainly in terms of energy autonomy and therefore of life period, for the batteries have to be too tiny. This is the reason why intensive research is being conducted nowadays on how to control sensor energy consumption within a network, taking communications into account as a priority. For this purpose we have proposed a method to calculate energy consumption within the wireless sensor networks according to the number of information packets sent, the number of nodes and, furthermore, we have succeeded in reducing energy consumption within the sensor networks.

Time-Reversal UWB Wireless Communication-Based Train Control in Tunnel

This paper reports an evaluation of UWB radio technology and Time-Reversal (TR) technique in tunnel environments for train-to-wayside communication. UWB technology has the potential to offer simultaneous ground-totrain communication, train location and obstacle detection in front of the trains. Time-Reversal channel pre-filtering facilitates signal detection and helps reduce interference. Thus, UWB-TR combination provides a challenging, economically sensible, as well as technically effective alternative solution to existing signaling technologies used in urban transport systems. This paper deals with deterministic channel modeling and its characterization in tunnel environment. It reports simulation performance evaluation of UWB-TR combinations in the developed channel model.

Positioning emergency calls along roads and motorways using a GSM dedicated cellular radio network

This paper presents a new alert and emergency warning system (EWS) concept based on a dedicated cellular radio network operated along highways and motorways. By offering some of the services defined under the intelligent transport system (ITS) initiative, it aims at enhancing and improving road safety. Some specific radio coverage aspects of this infrastructure are examined. Along this dedicated cellular network, the distress call location accuracy requirements are analyzed. The authors compare, in the context of cellular systems, different positioning techniques, derived from current research, including synchronization requirements and performance in multipath environment in order to define and evaluate the best approach for this specific system architecture.

Emergency calls location using TDOA technique along a motorway dedicated cellular radio network

This paper presents a new alert and emergency warning system concept based on a dedicated 2G or 3G cellular radio network operated along highways and motorways. By offering some of the services defined under the intelligent transport system initiative, it aims at enhancing and improving road safety. In order to locate emergency calls, the authors examine, in the context of the dedicated cellular system, the performances achieved by a time difference of arrival (TDOA) positioning technique. It then focuses on the requested physical infrastructure implantation accuracy.

Another Approach for Partial Parallel Interference Cancellation

In this paper, a technique for improving parallel interference cancellation (PIC) receivers with linear estimators is studied in a CDMA system under power control and near-far case. By multiplying the received signal for each user in early stages by a factor superior than unity, the proposed technique significantly reduces the harmful impact of the bias upon BER performance and requires only vector implementation under power control. In order to make the analysis more tractable, the proposed bias mitigation technique is described for a synchronous multi-user communication scenario with binary signalling, non-orthogonal multiple access interference in an additive white Gaussian noise channel.

Wide-band indoor localization effectiveness in presence of moving people

Recently, new standards have emerged in the telecommunication industry. These standards provide an open global specification that enables mobile devices to access and interact with information and services instantly. Paving the way to the emergence of new added-values services, these devices require more and more a localization agent. When deployed, these wireless resources have to operate in non-stationary propagation conditions and from outdoors to indoors. This paper concentrates on the evaluation of UWB radio signals used for localization, in presence of moving people modifying the indoor propagation channel. Different frequencies, bandwidths and densities of moving people are considered. Impacts of these parameters are evaluated on two different ranging methods: time of arrival (TOA) based and received signal strength (RSS) based.

Radio‐optic demonstrator for distributed antenna system indoor wireless applications using low‐cost VCSELs

Integration of wireless and optical networks would offer a potential solution for high bandwidth, mobility and cost reduction in the access networks. Radio over optical fibre (RoF) combines the capacity of optical networks with the flexibility and mobility of wireless access networks. In this paper, an economic demonstrator for RoF indoor applications is proposed using in-building pre-installed multimode fibre (MMF), low cost 850 nm VCSELs and 50 µm MMF pigtailed photodiodes. The system is dedicated to Distributed Antenna System (DAS) indoor wireless applications. To evaluate our system, error vector magnitude (EVM) measurements and eye-diagrams have been demonstrated. Copyright

A New Optimization Approach for Energy Consumption within Wireless Sensor Networks

The use of sensor networks should keep developing, mainly in such fields as scientific, logistic, military or healthcare applications. However, sensor size represents a significant limitation mainly in terms of energy autonomy and therefore of life period, for the batteries have to be too tiny. This is the reason why intensive research is being conducted nowadays on how to control sensor energy consumption within a network, taking communications into account as a priority. For this purpose we have proposed a method to calculate energy consumption within the wireless sensor networks, according to the number of information packets sent, the number of nodes. Furthermore, we have succeeded in reducing energy consumption within the sensor networks made up with nodes featuring differing data flow rates.