Find a copy in the library
Finding libraries that hold this item...
|All Authors / Contributors:||
Brice Djeumou; Pierre Duhamel; Université de Paris-Sud. Faculté des Sciences d'Orsay (Essonne),
|Description:||1 v. (pagination multiple IX-96-[11-26] p.) : ill. en noir et en coul. ; 30 cm.|
|Responsibility:||Brice Djeumou ; [sous la direction de] Pierre Duhamel.|
This thesis addresses the study of the user cooperation in wireless networks. The goal of the user cooperation is to increase user data rates and/or to improve communications efficiency. We have adopted both a Shannon theoretical approach and a practical approach. Our results in Shannon theory are obtained on some models of cooperative networks. We start with the basic model of cooperative network which is the relay channel and we derive a simple coding theorem for it. Remember that the main results on this channel model are due to Cover and El Gamal. Next we consider more elaborated cooperative networks in order to analyse the impact of inter-user interference. In a first time we consider the interference relay channel (IRC) for which we generalize the results of Cover and El Gamal on relaying strategies. Thereafter, in order to quantify the gain due to the degree of freedom that the cognitive radio allows in the use of the radio frequency spectrum, we introduce a new channel consisting of an IRC in parallel with an interference channel. For this later channel we adopt a game theoretical approach (existence and uniqueness of a predictable and stable state of the network: Nash equilibrium). For the practical approach of the user cooperation, in a first time, we propose two relaying protocols with low complexity levels namely Quantize-and-Forward and Clipped Amplify-and-Forward. Next, for cooperative networks with orthogonality at the receiver node, in order to mitigate the possible performance loss due to the use of the Maximum Ratio Combiner (MRC) and to take advantage (power gain or diversity gain) of the cooperation whatever is the SNR configuration of the network, we develop several new combining schemes.
- Réseaux d'information -- Thèses et écrits académiques.
- Moyens communication et information -- Thèses et écrits académiques.
- Radio cognitive -- Thèses et écrits académiques.
- Communications sans fils
- Théorie de Shannon
- Canal à relais
- Canal à interférence
- Stratégie de relayage