泛高斯干扰下无线随机网络物理层安全通信的研究

The eavesdroppers in the wireless networks bring up the issue of information security, and hence it is of vital importance to investigate the physical-layer secure communications. Due to the aggressive frequency resource reuse, interference is often inevitable in the networks. In the wireless stochastic networks, the interfering nodes often arrive at the network according to a Poisson point process, and the superimposition of multiple interfering signals constitutes the heavy-tailed generalized-Gaussian interference signal. It is the key to build the secure stochastic networks by utilizing the generalized-Gaussian interference to suppress the eavesdroppers. However, the analytical probability density function (PDF) of the generalized-Gaussian interference does not exist in general, and the mechanism about the effect of the interference on the system secrecy capacity is not clear. Hence, it is difficult to investigate the physical-layer secure communications for the wireless stochastic networks. In this project, we firstly provide an analytical approximation for the PDF of the generalized-Gaussian interference based on the Cauchy-Gaussian mixture model. From the analytically approximated PDF, we then analyze the system secrecy capacity in the generalized-Gaussian interference environments and reveal the mechanism about the effect of the interference on the system secrecy capacity. By maximizing the secrecy capacity, we further design a joint transceiver for the source and destination nodes, which provides a secure communication strategy for the wireless stochastic networks in the generalized-Gaussian interference. Finally, we allocate the spatial and power resources to enhance the system secrecy and realize green communications. The achievements of this project serve as reference for the secure communications of the future wireless networks.

无线网络的窃听节点给系统的信息安全造成了隐患，因此开展物理层安全通信的研究十分重要。由于频谱资源过度重复利用等原因，网络中干扰难以避免。在无线随机网络中，干扰节点常以泊松点过程的统计规律到达服务区，多干扰叠加构成了重拖尾的泛高斯干扰信号。利用泛高斯干扰抑制窃听节点的监听，是构建安全随机网络的关键所在。然而泛高斯干扰的统计分布难以解析表达，干扰影响通信安全容量的作用机理尚不清晰，这给随机网络安全通信的研究造成了困难。为此，课题主要研究：1）借助柯西-高斯混合分布模型，建立泛高斯干扰统计分布的近似表达；2）进而研究泛高斯干扰下系统的安全容量，揭示泛高斯干扰影响通信安全容量的作用机理；3）以最大化安全容量为目标，设计网络源-目标节点的联合收发机，建立泛高斯干扰下随机网络的安全通信方案；4）优化管理空间及功率等资源，提升网络的安全性能并实现绿色通信。课题的研究成果为未来无线网络的安全通信提供借鉴。

无线网络的窃听节点给系统的信息安全造成了隐患，因此开展物理层安全通信的研究十分重要。特别地，由于频谱资源过度重复利用等原因，网络中干扰难以避免，研究干扰环境下无线网络的工作机理及物理层安全传输，十分重要。为此，课题主要研究：1）为窃听节点下多用户多中继AF网络设计了三种用户中继调度方案，以有效地对抗系统窃听节点的监听，大幅提升了网络的安全通信性能。2）提出了Secure Switch-and-Stay Combining (SSSC)协议，大幅降低系统的复杂度，同时保证了物理层安全通信性能。3）针对中继处收到同信道干扰的影响，设计面向物理层安全的中继选择方案，并分析系统安全性能与优化。4）提出了中继处取模转发方案，同时在源节点处进行嵌套的网格编码。在发射端拥有信道状态信息时，理论上证明了取模转发方案对于所有信道都能接近系统最优安全容量。课题的研究成果发表在IEEE Transactions on Communications、IEEE Transactions on Wireless Communications、IEEE Transactions on Information Theory等国际知名期刊上，1篇论文入选ESI高被引论文。在本课题的资助下，项目负责人获得广东省自然科学杰出青年基金的资助，并获得广东省教育厅创新团队等项目的资助。