如何利用有限的频谱资源实现高效和可靠的数据传输，一直是无线通信领域关注的焦点。认知中继网络作为一种结合了认知无线电和协作中继技术的新型网络，有望解决上述问题。认知中继网络的性能与主用户和次级用户的空间分布特性密切相关。实际环境中，由于用户的频繁接入与断开、移动和主用户先验信息未知等，主用户和次级用户的空间分布具有空间随机性。传统认知中继网络研究较少考虑用户空间分布的随机性对系统的影响，阻碍其实际应用。针对该问题，本项目拟基于随机几何理论开展用户空间随机分布的认知中继网络（简称随机认知中继网络）研究。具体研究其中的次级用户发射功率控制策略、系统性能分析方法和非理想条件下有效的机会式传输方案等关键技术，探求用户的空间随机分布特性对认知中继网络设计与性能的影响。相关研究成果将为认知中继网络的实际部署提供重要的理论与技术指导。

How to effectively utilize radio spectrum resource is always the focus of academia and industry for wireless communications. Cognitive relay networks which combine cognitive radio and cooperative relay technique may solve the above mentioned problem. The performance of cognitive relay networks is closely related to the spatial distribution of primary users and secondary users. In a real-world network, the spatial distributions of primary users and secondary users are conceived as random due to users mobility and unknown prior information of primary users. However, few existing studies about cognitive relay networks take into consideration the effect from the spatial uncertainty of primary and secondary users. This project focuses on resolving the practical issue and proposes the research on cognitive relay networks with spatially randomly distributed primary and secondary users (i. e. random cognitive relay networks) based on stochastic geometry. Major contents of this proposal include the transmit power control scheme of secondary transmitters, performance analysis, and the effective opportunistic transmission strategy. The achievements of our research will be great benefits for practical applications of cognitive relay networks.