Réseaux cellulaires de cinquième génération ou 5G

International audienceRésumé La cinquième génération de réseaux sans fils cellulaires, plus simplement appelée 5G, ne devrait pas être disponible pour le grand public avant 2020. Cependant, la quantité d'innovations nécessaire et les enjeux financiers sous-jacents en font dès aujourd'hui un sujet majeur. Dans cet article, nous présentons le contexte et les services attendus de la 5G. En vue d'offrir ces services à des dizaines de milliards de terminaux, des travaux de recherche et de standardisation sont nécessaires. Un aperçu de ces travaux est donc inclus dans cet article. Nous présentons ensuite les évolutions technologiques pressenties pour la 5G, ainsi que des exemples d'architectures, qui commencent à faire consensus. L'article se termine sur les perspectives des chemins qui devraient nous mener jusqu'à la 5G

Association of power control and data rate selection in WCDMA

International audienceIn this paper, we study the interaction between power control and data rate selection in a wireless CDMA network. Specifically, third-generation cellular WCDMA system is considered. The criterion is the average of the sum of data rates in a variable rates services environment. Simulation results show that the association (or the integration) of power control and data rate selection allows a given network to have better achievable performance. Interesting elements of the proposed algorithm are highlighted and useful comments given.Association of power control and data rate selection in WCDM

Data rates and radio link adaptation in WiMAX

International audienceWiMAX is a very promising Broadband Wireless Access (BWA) System. Four digital modulations and many channel coding possibilites are provided in WiMAX which gives way for many modulation and coding schemes. We start by reminding these schemes and the associated robustness for each scheme. Link adaptation is the possibility to change modulation and coding scheme according to the radio link quality in order to have a high global efficiency. This procedure is not limited to WiMAX. For example, it was already included in GSM/EDGE. We remind the channel bandwitdhes and data rates of GSM/EDGE, UMTS and WiFi (in its two physical layer variants: 802.11a and 802.11b). The spectral efficiency of each system for the different proposed modulation and coding schemes are given. We also review some recent research paper

Le contrôle de puissance dans l'UMTS

International audienceLe contrôle de puissance dans l'UMT

Association of uplink power control and base station assignment in cellular CDMA systems

International audienceIn a wireless CDMA network a mobile is classically connected to the base station with the best received power level (R/spl times/L). The association (or the integration) of base station assignment with power control allows a given network to have better achievable performance. We investigate the association of base station assignment and power control in order to study the best achievable signal-to-interference ratio (SIR) behaviour. The existence of a feasible solution to the quality constraints problem, along with the choice of the base station assignment in order to have the minimal sum of transmitted powers, are discussed. This is done for a unique SIR target and for a multi-target environment. We also address two problems: the base station assignment as a function of network quality targets and best achievable performance which is represented by the highest achievable SIR for every possible BS assignment vector. This last value is computed with less computations than when it is directly calculated. Simulations show that appropriate base station assignment may give interesting capacity gains, especially for non-uniform distributions

WiMAX bandwidth reservation mechanisms : theory and practice

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Least interference routing for wireless ad-hoc networks

International audienceLeast interference routing for wireless ad-hoc network

Analysis of MAC protocols for Underwater Acoustic Data Networks

International audienceThis paper presents a state of art of existing Underwater Acoustic Networks. We study specifically the Media Access Control (MAC) Protocol design of research work done in this field. A comparison of different protocols is presented according to several criteria: propagation delay, node connectivity and energy consumption. This comparison allows us to present some ideas for a new design of a MAC Underwater Acoustic protocol