一种基于多径相对时延的密钥生成方法*

利用TDD系统上下行信道特征的一致性提取密钥，克服了现行密钥机制需要预分发的弊端，是保障物理层安全的一种新思路。针对宽带系统多径时延满足信道互易性的特点，设计了一种新的密钥生成方案。该方案在多径合并的同时提取各径间的相对时延，并计算相对时延与平均时延的差值生成密钥，具有较强的健壮性。超宽带信道的仿真结果表明，当信噪比等于15 dB时，密钥生成一致性可达95%。

Scheme of key generation based on multipath relative-delay

To overcome the drawbacks of the current key distribution mechanism,explored an alternative method for generating secret keys by exploiting the identical of channel characteristics between uplink and downlink in TDD system. As the multipath delay satisfied the channel reciprocity in wideband system, it designed a new key generation scheme. In which the receiver extracted the multipath relative-delay and generated the keys by calculating the difference between the relative-delay and the mean-delay. The simulation results utilizing the UWB channel demonstrate that the scheme has the robustness and the key agreement even equal to 95% when the SNR is 15dB.