Abstract: A two-layer centralized spectrum sharing scheme based on priority queue (PQTL-CSS) is designed for Cooperative Cognitive Radio Networks (CCRN). By recruiting a secondary user as relay, the primary transmission is accomplished with assistance. The proposed mechanism extends the traditional data cooperation to management collaboration, with which Cooperative Secondary User (CSU) coordinates the access of other cognitive nodes. Then, a two-layer centralized management structure is formed by the primary user and CSU corporately. On the premise that the highest priority of primary user is guaranteed, the CSU is given higher access authority in comparison with those non-cooperative secondary users, as a reward of assisting the primary's data transmission. Simulation is conducted with regard to the delay and throughput performance of different types of user. Results show that the proposed PQTL-CSS can achieve dynamic and highly efficient spectrum sharing of multiple types of node in the situation where traffic is of high randomness.

Key words: communication technology, cooperative cognitive radio networks, spectrum sharing, priority queue, delay