The Spectrum Detection and Allocation of Cognitive Radio Based on OFDM

Cognitive radio (CR) is viewed as a novel approach for improving the utilization of a precious natural resource: the radio electromagnetic spectrum. Spectrum sensing is a primary task of CR. At first, this article makes an overview of the background and concept of CR. Then focused on spectrum sensing of CR in OFDM, we put forward energy detection based on OFDM. Last this article provides two spectrum allocation algorithms: the irrigation algorithm with the capacity optimization and the revision greedy algorithm with the minimum interference to the authorized user. Simulation shows choosing more OFDM symbols and appropriate threshold can make the total possibility of error detection reach the least and the revision greedy algorithm is suited for the CR spectrum allocation.