With the rapid advancement of unmanned aerial vehicle (UAV), ensuring the security of communication links among UAVs has become crucial. In this paper, we propose a novel physical layer key generation scheme based on channel codeword reconstruction. In UAV communications, the high mobility of aerial nodes leads to short channel coherence time, which together with noise causes inevitable channel estimation errors. These errors significantly degrades the performance of wireless channel-based key generation. Therefore, we propose a codeword construction algorithm that achieves a polarization characteristic, which effectively segregates reliable keys from unreliable ones. Compared to the existing quantization-based key generation scheme, our approach maximize the utilization of raw channel information and employ soft-decision decoding to generate key. Simulation results demonstrate that the proposed scheme reduces the key disagreement rate for legitimate users and increases the number of consistently generated keys. Furthermore, our method ensures a lower key consistency rate for eavesdropper, which guarantees system security.

翻译：随着无人飞行器技术的快速发展，确保无人机间通信链路的安全性变得至关重要。本文提出了一种基于信道码字重构的物理层密钥生成新方案。在无人机通信中，空中节点的高机动性导致信道相干时间较短，与噪声共同作用会引发不可避免的信道估计误差，这些误差显著降低了基于无线信道的密钥生成性能。为此，我们提出了一种具有极化特性的码字构建算法，该算法能有效区分可靠密钥与不可靠密钥。与现有基于量化的密钥生成方案相比，本方法最大化利用了原始信道信息，并采用软判决解码生成密钥。仿真结果表明，所提方案降低了合法用户的密钥不一致率，同时增加了持续生成的密钥数量。此外，本方法使窃听者获取的密钥一致性率更低，从而保障了系统安全性。