International Journal of Computer Applications
In wireless communication system, radio spectrum is the most valuable and limited resource. Due to traditional fixed spectrum allocation policy, there is a problem of spectrum under-utilization in licensed band whereas an unlicensed band is getting overcrowded. A new device called Cognitive Radio (CR) is introduced which allows unlicensed users to access licensed spectrum, without interfering with the operation of licensed user. Cognitive radio follows dynamic spectrum access policy which makes it more vulnerable to the various attacks compared to traditional policy.