出版社：Mediterranean Center of Social and Educational Research (MCSER)
摘要：Today's wireless networks are characterized by fixed spectrum assignment policy. The limited available spectrum and the inefficiency in the spectrum usage necessitate a new communication paradigm to exploit the existing wireless spectrum opportunistically. This new networking paradigm is referred to as Dynamic Spectrum Access (DSA) and cognitive radio networks. Cognitive radio is a paradigm for wireless communication in which either a network or a wireless node changes its transmission or reception parameters to communicate efficiently avoiding interference with licensed or unlicensed users. In practice, the spectrum allocated to licensed primary users is not utilized properly. The secondary unlicensed users can sense and utilize the unutilized spectrum
