Abstract
Cognitive Radio (CR) is an emerging approach for a more efficient usage of the precious radio spectrum resources, which it considers an expanded view of the wireless channel by managing and adapting various dimensions of time, frequency, space, power, and coding. In this paper, we define the system requirements for cognitive radio, as well as the general architecture and basic physical and link layer functions. In order to self-adapt the UWB pulse shape parameters and maximize system capacity while co-exist with in-band legacy NB systems (WiFi and FWA) in the surrounding environments.