A cell based dynamic spectrum access scheme

Today´s wireless networks are characterized by a fixed spectrum assignment policy. However, a large portion of the assigned spectrum is utilized from 15% to 85% with a high variance in time. Cognitive radio can improved the spectrum efficient through dynamic spectrum access. In this paper, a scheme is proposed in which cognitive radio networks (CRN) collaborate with primary radio networks (PRN) to manage spectrum. On condition that the primary user is protected, cognitive node is controlled by the cognitive base station to communicate with the primary base station as a pseudo normal user. For a cognitive node lies the region of several PRNs, the enough access chance will offer abundance channel for the cognitive node, which is approved by the simulation results for the spectrum efficient is increased.