Cognitive Radio: A Technological Review on Technologies, Spectrum Awareness, Channel Awareness, and Challenges

Radio spectrum is a limited resource in this world of broadband connections. With the increase in demand of digital wireless communications in commercial and personal networks judicious use of frequency spectrum has become a serious concern for wireless engineers. Cognitive adios (CR) are a solution to this clustered spectrum issue nowadays. Cognitive radio or SDR is a new concept/technology which is being implemented to maximize the utilization of radio spectrum. At any time, unused frequency spectrum can be sensed by cognitive radio from the wide range of wireless radio spectrum. So, as a result this gives really an efficient utilization of radio resources. Major factors that govern cognitive radio network (CRN) are related to service contradiction, routing, and jamming attacks which may interfere with other operating wireless technologies. Thrust areas in developing a good CR lies in the efficient algorithm design for spectrum sensing, spectrum sharing, and radio re-configurability. This paper presents an overview of required technologies, spectrum and channel awareness, and challenges of cognitive radio.