The International Journal of Innovative Research in Computer and Communication Engineering
The wireless communications are generating the spectrum shortage problems with the reference to the latest developments. The more challenges in the use of licensed wireless networks or unlicensed wireless networks with opportunistic use of the spectrum with limited rules or without limited rules. The different frequency bands are used by different wireless networks. So it's very important to use attenuation bands when there is no activity occurs on them. A new technology which leads like cognitive radio is to solve these problems through dynamically utilization of rules and spectrum.