随着无线通信技术的快速发展，网络容量与传输速率实现了显著提高，然而频谱资源受限仍是制约无线通信系统未来发展以及网络容量进一步提高的重要因素。因此，为了缓解频谱资源相对匮乏的现状，实现频谱资源的灵活使用，研究认知无线电技术具有重要意义。本项目拟使用统计队列分析理论，针对多用户认知网络中的时延服务质量保障、能量收集与能效优化、信息安全传输三个重要问题进行深入研究。在时延服务质量保障方面，我们将面向无线业务多样化的时延需求，研究统计时延服务质量保障技术，实现多用户认知网络中主用户与认知用户时延服务质量的精确保障；在能量收集与能效优化方面，我们将研究认知网络中基于随机能量收集的传输与能效优化策略，在满足网络服务质量需求的基础上实现认知网络能量的高效利用；在信息安全传输方面，我们面向无线业务对信息安全的不同需求，研究新型的安全传输方案，实现认知网络安全等级的精细化描述和多样化安全需求的精确保障。

With the rapid development of wireless communications technologies, the network capacity and data transmission rate have been significantly increased. However, the constrained spectrum resources are still one of the main factors that limit the future development of wireless communications systems and the further improvement of network capacity. Consequently, to alleviate the “relatively shortage” of wireless spectrum resources, it is critically important to study the cognitive radio technologies. This project will employ the theory of statistical queueing analysis and perform three crucial issues of cognitive radio networks, which are delay quality-of-service (QoS) provisioning, energy harvesting and energy efficiency optimization, and information security transmission, respectively. Specifically, for the delay QoS provisioning, we will consider the diverse delay requirements of different wireless services and realize the accurate delay QoS provisioning of distinct wireless applications for primary and cognitive users over multi-user cognitive radio networks. For the energy harvesting and energy efficiency optimization, we will study the stochastic energy harvesting based cognitive transmission schemes as well as the energy efficiency optimization strategies such that we can efficiently utilize the limited energy while satisfying the QoS requirements of cognitive radio networks. For the information security transmission, we will develop the novel secure transmission schemes by considering the distinct security-level demands of different wireless services such that we can accurately characterize the diverse security-level demands and realize the efficient security protection for cognitive radio networks.