Primary User Detection in Multi-Antenna Cognitive Radio
Oscar Filio, Serguei L. Primak, Valeri Ya. Kontorovich · InTech eBooks · 2011
It is well known in the wireless telecommunications field that the most valuable resource available is the electromagnetic radio spectrum. Being a natural resource, it is obviously finite and has to be utilized in a rational fashion. Nevertheless the demand increase on wireless devices and services such as voice, short messages, Web, high-speed multimedia, as well as high quality of service (QoS) applications has led to a saturation of the currently available spectrum. On the other hand, it has be found that some of the major licensed bands like the ones used for television broadcasting are severely underutilized Federal Communications Commission (November) which at the end of the day results in a significant spectrum wastage. For this means, it is important to come upwith a new paradigm that allows us to take advantage of the unused spectrum. Cognitive radio has risen as a solution to overcome the spectrum underutilization problem Mitola & Maguire (1999),Haykin (2005). The main idea under cognitive radio systems is to allow unlicensed users or cognitive users (those who have not paid for utilizing the electromagnetic spectrum), under certain circumstances, to transmit within a licensed band. In order to perform this task, cognitive users need to continuously monitor the spectrum activities and find a suitable spectrum band that allows them to: