Dynamic spectrum access with cognitive radios: Future architectures and research challenges

New trends and developments in radio technology together with current developments towards liberalization of spectrum management regulations are opening the opportunity to exploit the new paradigm of dynamic spectrum access (I)SA). The key characteristic of DSA systems is their ability to exploit knowledge of their electromagnetic environment to adapt their operation and access to spectrum. Their key promise is that they open the possibility of highly efficient (re)use of spectrum. The cognitive radio, built on software defined radio, is the intelligent, adaptive and frequency agile wireless device that will underlie most forms of DSA. In this paper we review proposed architectures for future DSA systems and describe some of the key research challenges associated with this new paradigm. Particular emphasize is given to autonomous cognitive radio DSA.