Cognitive Radios: A Survey of Methods for Channel State Prediction

With the increasing demand of wireless application, the insufficiency of the electromagnetic radio spectrum is getting more and more serious. Spectrum is regulated by governmental agencies that license their use to individuals or organisations on a long-term basis, normally over huge geographical regions. The Nov. 2002 report of the FCC speaks of spectrum access in many bands as a more significant problem than the scarcity of spectrum itself, owing mainly to the restrictions imposed by the legacy command-and-control regulations over the potential spectrum users [1]. Due to this, precious resources go wasted for large-frequency regions are used very sporadically.