Application de la logique floue aux techniques d'accès multiples par répartition des codes CDMA

· En CDMA (Code Division Multiple Access) les codes utilisés sont générés à l'aide des systèmes à registres. Toutefois ceux-ci présentent plusieurs inconvénients: la connaissance du nombre de registres ainsi que leurs connexions internes permet de produire la même séquence et l'utiliser ensuite pour écouter les conversations des autres ou bien les falsifier. On se propose d'implanter un modèle de génération de séquence qui serait purement aléatoire pour remplacer le générateur classique. Ceci est modélisé par un processus basé sur les principes de la logique floue moyennant certaines règles et certaines conditions initiales

Nash Equilibrium Study for Distributed Mode Selection and Power Control in D2D Communications

One of the main challenges of LTE-advanced (LTE-A) is to recover the local-area services and improve spectrum effciency. In order to reach those goals technical capabilities are required. D2D is a promising techniques for the 5G wireless com- munications system using several applications, as: network traffic offoading, public safety, social services and applications such as gaming and military applications. In this chapter, we investigate both mode selection and distributed power control in D2D system. Indeed, the mode selection is provided while respecting a predeter- mined SINR threshold relative to cellular and D2D users. The amount of minimum and maximum power are then derived to fulffill the predetermined requirements, by limiting the interference created by underlaid D2D users. In order to realize our proposed power control step, a new distributed control approach is proposed using game theory tools for several cellular and D2D users. This distributed approach is based on the mode selection strategy already proposed in the previous step. Finally, simulations were established in order to compare the proposed distributed algo- rithm in terms of coverage probability which is based on game theory, with other conventional centralized algorithms