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|All Authors / Contributors:||
Ilhem Ouachani; Pierre Duhamel; Université de Paris-Sud. Faculté des Sciences d'Orsay (Essonne).
|Description:||1 vol. (199 p.) : ill. ; 30 cm.|
|Responsibility:||Ilhem Ouachani ; sous la direction de [Pierre Duhamel].|
Wireless systems are now popular worldwide to help people and machines to communicate with each other independentlyof their location. Hence, the demand for capacity in cellular and wireless local area networks has grownin a literally explosive manner during the last decade. But, data transmission over wireless communication suffersfrom several channel impairements such as fading and cochannel interference. An efficient technique to mitigatethe fading and increase the communication link robustness is the spatial diversity.This thesis deals with the perfomance analysis of wireless communication systems exploiting spatial micro- andmacro-diversity. The first part is concerned with the investigation of Multiple-Input Multiple-Output (MIMO)systems using Orthogonal Frequency division Multiplexing (OFDM), in the micro-diversity context. It is shownthat taking into account the real channel delay profile can have an impact on the MIMO/OFDM system ergodic andoutage capacities, when a parametrized cannel model is considered. Then, two space-time block coding schemesare proposed for a MIMO/OFDM system using two transmit antennas. The second part deals with the performance of wireless systems exploiting spatial macro-diversity. First, a realisticchannel model based on a refinement of the Radio-Frequency Fornt-End (RFFE) is proposed. The impact ofthis realistic channel model on ergodic capacity is investigated. Then, an optimal power allocation algorithm is proposed for the two-relay regenerative paralleltransmission system. This optimization, subject to a cartain power budget to be allocated between the two relays,is done in order to minimize the BER at the destination.