JWCN_V2_N3_RP1 N. Elayabharathi M. Poonguzhali B. Pradeep Raja K. Yalini Journal On Wireless Communication Networks 2320 - 2351 2 3 1 7 Cognitive Radio Network, Spectrum Sharing, Dynamic Queuing Algorithm, Cognitive Radio User or Secondary User, Primary User, Cooperative relay Cognitive Radio Network (CRN) and Cooperative Communication provides a new environment in wireless network which can effectively improve the spectrum efficiency of future wireless network. In this paper, a two phase protocol based cooperative relaying for a secondary user along with decode-and-forward (DF) and amplify-and-forward (AF) relaying system is proposed. In the proposed protocol, a dynamic queuing algorithm is used to access and manage the spectrum from a Primary User (PU) to the Secondary Users (SU) without any conflicts between the cognitive users (CR) or Secondary Users (SU) for accessing the same available spectrum. A Multi Behaviour Node System (MBNS) is used to achieve better outage performance for the secondary system when it fails from a relay selection. The proposed scheme achieves the effective spectrum sharing and hence the overall system performance is improved. The simulation result shows the improvement over DF and AF relaying system. October - December 2013 Copyright © 2013 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=2553