Cognitive radio – State of the Art

Abstract

The wireless technology is growing very quickly, in the actuality the new technologies applied to the radius link appear with a multiplicity of names that change as the application and the use that do of them: Bluetooth, GSM, Microwaves, Links Satellites, Wi-Fi, WiMax, ZigBee, etc. Each system uses a hardware and devoted software and exclusive chord to his functionalities to send and receive the waves of radio. Some of these bands of the spectrum can justify by the fact that some applications work better in determinate spaces inside the spectrum electric radio. This exponential growth of wireless applications creates an every time main demand of spectrum electric radio what has motivated the research of technologies of radio that can scalar to satisfy the future demands, so much in terms of efficiency of spectrum and performance of the applications.