176 страниц. 2014 год. LAP Lambert Academic Publishing Nowadays, depending on the purpose, the geographical region, the particular carrier, and many other factors, the electromagnetic spectrum assigned to wireless networks is controlled by governmental agencies. Increasing demands on the radio spectrum have driven wireless engineers to rethink approaches by which devices should access this natural, and arguably scarce, resource. Cognitive Radio has arisen as a new wireless communication paradigm aimed at solving the spectrum underutilization problem. In this book, the authors explore a novel variety of techniques aimed to find unused portions of the electromagnetic spectrum and take advantage of them in an opportunistic manner.