Wireless technology is advancing fast in the modern world, and nature of this technology assure us with the abundance of perks such as IOT i.e. Internet of Things which is the near future. It has not limited to common wireless devices such as Laptops, smartphones, etc., but has a much wider influence on devices which we cannot even imagine about such as Smart homes which uses sensor technologies. Some of the examples are Google Home Mini: A Smart speaker, Misfit Bolt: Bluetooth smart bulb, etc. This outburst of wireless applications results in increasing demand for more space in spectrum. Some researchers have even revealed that most easily usable spectrum bands are not being used appropriately. This problem gives us the motivation to find out something which can be used to meet future requirements of spectrum efficiency.
Cognitive radio is the emerging technology which can be helpful in this aspect as it analyses the spectrum and the CR transceiver senses that which spectrum is unused, then it allocates the spectrum to the users or applications which are facing limitations which results in better application performance and effective use of spectrum. The FCC view: “A cognitive radio (CR) is a radio that can change its transmitter parameters based on interaction with the environment in which it operates.” It is a software proposed radio with cognitive software which automatically adjusts with an environment it senses. It is a step by step process – Radio-Scene Analysis-> Channel Identification->Transmit-power control and dynamic spectrum management. We will dig deep into each process in the later part.
Spectrum sensing, that is, sensing the existence of the major users in a licensed spectrum, is a central problem for cognitive radio. As a result, spectrum sensing has recreated as a very active research area in recent years despite its long history.
Cognitive radio system has numerous applications. It helps in improving spectrum utilization and efficiency, improving link reliability, providing cheap radios, advanced network topologies, IOT, Automatic radio resource administration.
We can expect that the cognitive radio technology will soon be visible from laboratory experiments to outside world programmable radio that will work as a worldwide program for wireless development.