Users first listen to the spectrum allocated to the licensed users to detect the state of the licensed users. Based on the detection results, cognitive radio users decide their transmission strategies. If the licensed users are not using the bands, cognitive radio users will transmit over those bands. If the licensed users are using the bands, cognitive radio users share the spectrum bands with the licensed users by restricting their transmit power.
Published in Chapter:
Tunable RF Front-Ends and Robust Sensing Algorithms for Cognitive Radio Receivers
L. Safatly (American University of Beirut, Lebanon), A. H. Ramadan (American University of Beirut, Lebanon), M. Al-Husseini (Lebanese Center for Studies and Research, Lebanon), Y. Nasser (American University of Beirut, Lebanon), K. Y. Kabalan (American University of Beirut, Lebanon), and A. El-Hajj (American University of Beirut, Lebanon)
Copyright: © 2015
|Pages: 32
DOI: 10.4018/978-1-4666-6571-2.ch003
Abstract
In this chapter, the concepts of Cognitive Radio (CR) and multi-dimensional spectrum sensing are introduced. Spectrum sensing methodologies, energy efficiency consideration, resources scheduling, and self-management and learning mechanisms in cognitive radio networks are also discussed. The entailed challenges of CR RF front-end architectures are looked into. The synthesis and design performance analysis of a tunable RF front-end sensing receiver for CR applications are presented. The chapter also discusses how sensing performance degradation, which is due to RF impairments, is analytically evaluated. Spectrum sensing algorithms that correct imperfect RF issues by compensating induced error effects through digital baseband processing are also illustrated.