From software defined radio to cognitive radio

Higher data rate demands and better Quality of Service (QoS) requirements have resulted in the development of a number of wireless communication standards. Each standard has its own baseband and RF parameters with its own specific hardware platform. Software Defined Radio (SDR) unites all these current as well as future wireless standards on a single hardware platform where all the baseband processing is performed in digital domain. Thus a radio downloads the relevant software on its air interface and executes it on a reconfigurable hardware. A step ahead from a reconfigurable radio is Cognitive Radio (CR) which is about making a radio intelligent with the help of sensors. Based on the information collected through sensors, a radio adapts its physical layer parameters to efficiently make use of the radio resources.