A Novel Cooperative Cognitive Radio Spectrum Sharing Protocol Based On Priority Queue

With the fast development of wireless communications demand, the contradiction between the scarcity of spectrum resource and low utilization of spectrum resource becomes the barrier that impedes the rapid development of future mobile communications. Cognitive Radio(CR) technology can actively sense wireless communications environment and dynamically access idle spectrum band that is unused by Primary User(PU), thus creates a new method to resolve the abovementioned contradiction. However, the dynamic and complexity of spectrum resource bring challenges to the design and implementation of CR systems.In this paper, a two-layer centralized spectrum sharing scheme based on priority queue(PQTL-CSS) is proposed for cooperative cognitive radio network(CCRN). By recruiting secondary user as relay, primary transmission is assisted and accomplished. The proposed mechanism extends the traditional data cooperation to management cooperation, with which cooperative secondary user(CSU) coordinates the access of other cognitive nodes. Thus a two-layer centralized management structure is formed by the primary user and CSU cooperatively. On the premise that the highest priority of primary user is guaranteed, CSU is given higher access authority in comparison with those non-cooperative secondary users, as a reward of assisting the primary transmission. The proposed mechanism can efficiently solve the resource allocation problem among cooperative cognitive node and non-cooperative cognitive nodes and realize a dynamic and high efficient spectrum sharing among various types of nodes under more stochastic nodes’ coming traffic of nodes. The proposed protocol studies data transmission of various types of users in cooperative cognitive networks and devise an access scheme based on the difference between requests and admissions. Considering the effect of network typology and the dynamic nature during communications, primary user can periodically initiate channel detection to select appropriate cooperative cognitive node, and update the cooperative cognitive node based on network status. Consequently, the data transmission performance can be guaranteed. Then, the dissertation applies the devised protocol to cognitive tactical network and makes corresponding adjustments according to the characteristics of cognitive tactical networks. Theoretical analysis and numerical simulation are conducted with regard to the delay performance of different types of users. Numerical simulation is also conducted with regard to the throughput performance of different types of users. Results show that the proposed PQTL-CSS could achieve dynamic and high efficient spectrum sharing among multiple types of nodes under a stochastic coming traffic. Besides, simulation results also reveal that the delay of cooperative cognitive node is smaller than that of traditional method.