基于多节点分组协作干扰的无线物理层安全传输

Grouping cooperative jamming for wireless physical layer security

针对无线通信的安全传输问题,提出了一种新的多节点分组协作干扰以增强安全的策略.在源节点发送私密信息的同时,传统协作干扰策略中所有的协作节点发送公共的人工噪声干扰窃听用户,而分组协作干扰策略中协作节点分组发送不同的人工噪声.为了保证人工噪声不干扰目的节点,协作干扰策略的波束形成系数的设计基于迫零准则.在节点独立功率约束的条件下,传统干扰策略无法有效的利用所有协作节点的阻塞功率,而分组干扰策略将每两个信道增益接近的节点划分为一组,从而保证组内的协作节点能近乎完全利用可用的阻塞总功率.仿真结果验证了最小距离分组干扰策略利用的阻塞总功率最大,也对应最大的平均安全速率.为更易于实现,文中还提出了基于相对距离的固定分组策略.除此之外,文中还考虑了人工噪声泄露的情况,此时传统协作干扰策略完全失效,而分组协作干扰策略即便是只有一组有效,也可以保证平均安全速率依然随协作节点最大发射功率增大而增大.实验结果证实了分组协作干扰策略要优于传统协作干扰策略.

In this paper, we propose a novel scheme of grouping cooperative jamming （C J） for secure communi- cation. During the data transmission, the source broadcasts its information signal, all the helpers simultaneously transmit common artificial noise （AN） to interfere the eavesdropper for tradition CJ. In our scheme, all the helpers are divided to different groups which transmit independent artificial noises to the potential eavesdropper. The zero-forcing beamfomer is selected to cancel the AN out at the destination. The tradition CJ scheme can not completely consume the total power budget, while the grouping scheme is based on the instantaneously channel gain which can make best of the total power per group. The simulations show that our propose scheme based on minimum distance achieves the highest secrecy rate and the power actual consumed approaches to the total power budget. Additionally, we propose a fixed grouping scheme based on the second-order statistics of the channel gain which can be easily implemented. Furthermore, we consider the case that the eavesdropper has knowledge of the artificial noise. The tradition CJ does not work in such case, while our scheme works well even only one group keeps its AN secret. The analytical results and simulations show our scheme achieves better performance than the tradition CJ.