Abstract
Wireless Networks are limited in energy and resources, are subject to development constraints. The difficulties are such as the increasing RF spectrum saturation and efficient path discovery. The Cognitive Wireless Networks, leaning on a form communication model, develop new strategies to mitigate the inefficient use of the spectrum. The first application of the concept of cognitivity to communications was focused on exploiting the dynamics in spectrum utilization (cognitive radio), nevertheless network-wide deployment of such concepts is foreseen in the framework of the "cognitive networks", where the cognitive process will be employed to support end-to-end network-wide goals such as QoS. This paper presents a state-of-art of cognitive networks and proposes a framework, architecture for cognitive networks. This paper will also discuss mechanisms for self-adaptation, learning and evolutionary functionalities to support users/applications end-to-end goals.