多天线系统中面向物理层安全的极化编码方法

Polar Code for Physical Layer Security in Multi-antenna Systems

该文提出一种基于多输入信道最大容量差映射的极化安全编码方法,通过适当降低信道极化速度达到提高安全传输速率的目的。首先,利用信道极化结构,将极化后的逻辑信道按信道质量划分为好信道与差信道两类;然后,通过具体的逻辑信道删除率迭代分析,提出一种能够有效提升差逻辑信道容量并降低好逻辑信道容量的最大容量差信道映射方法,达到降低信道极化速度的目的;最后,利用加权修正合法信道与窃听信道最大容量差映射结果,实现多输入信道下的极化安全编码。仿真结果表明,在极化阶数n=9的二进制删除信道下,所提方法相比随机映射与Arikan方法,安全传输速率分别由0.029,0.004提升到了0.042,并且所提方法同样适用于衰落信道场景。

A maximal-capacity-difference mapping-based secrecy polar coding method is proposed. It improves the secrecy rate by reducing the channel polarization speed. First, the polarized channels are divided into two categoryies based on the polarization structure： the good quality ones and the bad quality ones. By analyzing the eraser rates of the polarized channels, a maximal-capacity-difference mapping method is proposed. Through improving the capacity of the bad polarized channels and reducing that of the good polarized channels, the channel polarization speed decreases efficiently. Finally, weighting is adopted to modify the maximal-capacity-difference mapping results between legitimate channels and wiretap channels, thus the secrecy polar coding in multi-input channel is implemented. Simulation results verify that the secrecy rate of proposed method in binary erasure channels can be increased from 0.029 and 0.004 to 0.042, compared to the random mapping method and Arikan＇s method at polarization order n =9, respectively. And the proposed method also works in fading channels.