DWDM/OOC and large spectrum sources performance in broadband access network

This work presents a performance evaluation based on elaborated analytical expressions of error probability for broadband access network in the case of a combined technique of dense wavelength division multiplexing (DWDM) and one dimensional optical orthogonal codes (1D-OOC). Optical sources with relatively large spectrum has been considered and simulated. Besides the Multiple Access Interference (MAI) at the receiver due to the access method which is optical code division multiple access (OCDMA), the emitted radiation of these sources in a dense WDM communication link introduces additional interference. Conventional correlation receiver (CCR) and parallel interference cancellation (PIC) receiver limitations are discussed. This paper has investigated the kind of optical sources with large spectrum bandwidth which could be accepted for a targeted bit error rate (BER) and given number of users in broadband access network supporting DWDM with optical orthogonal codes.Comment: (IJDPS) Vol.3, No.3, May 2012, International Journal of Distributed and Parallel Systems (IJDPS) Vol.3, No.3, May 201

Architectures de systèmes multi-antennes et estimation de canal

Ces travaux portent sur l étude des systèmes multi-antennes solution fort probable des réseaux sans fil de nouvelle génération. Deux aspects essentiels y sont abordés : le codage spatio-temporel et l estimation de canal. Après une présentation du décodage STBC, du décodage STTC ainsi que les systèmes en couches en supposant le canal parfaitement connu par le récepteur, différentes méthodes d estimation de canal sont présentées. Un nouvel algorithme EM d estimation de canal et de décodage de système turbo Blast OFDM est proposé. Des techniques semi aveugle d estimation de canal à savoir la méthode des sous espaces et ses variantes puis une nouvelle approche générale d estimation de canal pour les systèmes MIMO OFDM sont considérées. La diversité coopérative est une alternative des systèmes MIMO. Une introduction aux techniques d estimation de canal de ces systèmes dits distribués est intégrée dans ce document. Les résultats des diverses simulations permettent d apprécier les performances de ces algorithmes.This work concerns the study of multiple antenna systems which are expected to be a promising solution for the next generation of wireless networks. Space-time coding and channel estimation as two essential aspects of wireless networks were addressed in this manuscript. We first assume that the channel is perfectly known and in this case STBC, STTC decoding and layered systems were presented. In addition various appropriate methods of channel estimation were considered and applied to above-mentioned decoders. For Data Aided scheme, we have considered variety of channel estimation methods ranging from direct least-square methods to iterative optimization. A new joint channel estimation and decoding EM algorithm is proposed and applied to OFDM turbo blast detectors. For semi-blind techniques, various subspace method were mentioned. Moreover a new MIMO OFDM channel estimation is proposed. The problem of channel estimation for distributed antenna is outlined. Besides, there are lots of numerical results that show the performance of these algorithms and justify our new methods.LIMOGES-BU Sciences (870852109) / SudocSudocFranceBeninFRB

Uplink Rate Based on Massive MIMO Channel Estimation Approach

International audienc

Global approach of mean service satisfaction assessment

A theoretical expression for mobile service satisfaction assessment has been proposed. Mobile networks users’ satisfaction is a major concern for the operators and regulators. Therefore a certain level of network qualification is required to be offered to consumers by operators thanks to the decisions initiated by the regulation authority. For the assessment of the level of satisfaction, several methodologies and tools (measuring and monitoring) have emerged. Ranking in two broad categories, namely the objective and subjective methods, both have advantages as well as disadvantages. This Letter has proposed a unified approach to evaluate more objectively users’ level of satisfaction of a service based on the most common network key performance indicators (KPIs) rate following the different methods. This approach's main advantage is that it has taken advantages of the different positive aspects of the existing methods and outperformed their limitations thanks to the introduced concept of global KPI. In addition, the size of samples according to each method has been considered. A mean service satisfaction theoretical expression has been proposed to regulation authority, consumers association and operators as common base of service satisfaction assessment

Assessing the Radio Access Technologies Impact on the Universal Access Index

International audienc

Predicting telemedicine system user satisfaction in sub-Saharan Africa

During our literature review and on-site research in developing countries, particularly in Sub-Saharan Africa, we could not point out any efforts to measure the Quality of Service (QoS) and Quality of Experience (QoE) provided by telemedicine systems, thus making it impossible to understand their overall levels of user satisfaction in sub-Saharan African countries. Therefore, we conducted a qualitative and quantitative study, with experiments to measure QoS performance and the end-user QoE perception of telemedicine systems. Based on obtained results, we propose a mathematical formula to predict the QoE based on QoS measurement values, since a known relationship exists between QoS and QoE