The multiple prioritized access mechanism of Cognitive Networks

Developments of wireless communication technology need higher standards of reliability of network and full utilization of resources. The proposition of Cognitive Network improves the utilization of frequency spectrum effectively. Main tasks of this paper are to introduce EDCA mechanism into the Cognitive Networks and validate if it can guarantee the classified service access effectively. First of all, we develop an access control for the Cognitive Networks, which adapts the EDCA mechanism of WLAN and sets different priorities for Cognitive users. Secondary, we propose a new prioritized access control algorithm for Cognitive Network, which adapts Linear Backoff Algorithm, Stall Avoidance Scheme etc. to enhance the performance. Finally, we use and extend NS2 to satisfy the Multi-priority access with multi-interface and multi-channel. Primary User and Cognitive Users connect to the same node, which satisfies multi-interface and multi-channel. We can reach the conclusion that the performance of Cognitive Network used mechanism of EDCA is better than that of used mechanism of DCF. The spectrum utilization of Cognitive Network is higher than that of Non-cognitive Network. Primary Users would not be interfered by Cognitive User.