Literature Review of Resource Allocation Methods in Cognitive Radio Networks

Cognitive radio network (CRN) is growing worldwide which leads such networks are suffering from the challenges of efficient spectrum/resource allocation as well as lack of spectrum. Efficient spectrum allocation technique becomes new research problem in use of CRN. A major challenge to this new technology is how to make fair assignment of available spectrum to unlicensed users. The appropriate allocation of idle frequency spectrum coexisting cognitive radios while maximizing total bandwidth utilization and minimizing interference is required for the efficient spectrum utilization in CRN. The method of fixed spectrum allocation resulted to less spectrum utilization over the entire spectrum. For cognitive radio systems, Orthogonal Frequency Division Multiplexing (OFDM) widely used data transmission method which delivering the flexibility for allocating the resources under the dynamic conditions. Therefore, OFDM based CRN networks having major challenge of resource allocation. There are different situations and parameters in dynamic environment which are impacting on total system data rate performance. In this paper, we are presenting the survey on cognitive radio networks, spectrum sensing, challenges and different recent methods analysis for resource allocation.