Cognitive Radio Communications and Software Defined Radio

Increasing demands for high speed wireless access gave rise to new approach to radio communications and spectrum management – Cognitive Radio (CR). One of the key components of cognitive radio – dynamic spectrum access – shows a way to overcome the scarcity of one of the natural resources – radio frequency spectrum. The research in the domain of CR spans the wide area from information and signal theory, physical and MAC layer architectures or network theory to economic, legal and policy issues. Moreover, the future of cognitive radio would not be possible without the advances in the software defined radio architectures, signal processing or intelligent learning and optimization algorithms. This special issue of Radioengineering journal thus aims to gather the innovative contributions in the broad domain of cognitive radio and reconfigurable software defined radio and present them to the reader interested in this recent exciting area.