Foreword-cognitive radio: From equipment to networks

The 2009 special issue of Ann. Telecommunication presents several papers on cognitive radio, which is a growing technology. The special issue begins with a paper from Joseph Mitola 'Cognitive radio architecture evolution', which presents an overview of dynamic spectrum access and then goes on to show how cognitive radio architectures can evolve towards a quality of experience. In the second paper entitled 'An executable metamodel of a hierarchical and distributed architecture management for cognitive radio equipments,' Loïg Godard, Christophe Moy, and Jacques Palicot propose a design framework to integrate all necessary elements to manage the cognitive features of a cognitive radio. Christian Doerr, Dirk Grunwald, and Douglas C. Siker, in their article 'Local control of cognitive radio networks,' propose swarm intelligence as a good means of efficient coordination of cognitive radio networks using local information only.