中文摘要：

在通过公共无线信道生成密钥的过程中,信道特征序列之间的相关性不容忽视。相关文献提出,利用Karhunen-Loève变换完成特征序列的去相关时,具有较明显的敏感性[1-3]。本文对Karhunen-Loève变换的敏感性展开了进一步的分析,并提出了一种改进的Karhunen-Loève去相关算法来去除敏感性。在改进算法中,需要通过公开信道来传输额外信息,但所公开的信息可以被有效控制,使得窃听者获得的信息尽可能少。仿真结果表明,利用提出的改进方案可以有效降低密钥的不一致率。同时,本文采用简单的CASCADE协商协议对密钥进行协商,说明改进算法可以提高单位时间内生成密钥的长度。

英文摘要：

In this paper, we consider establishing secret keys using the common wireless channel, with particular emphasis on the temporal correlation of channel coefficients. In literature, it was reported that the Karhunen-Loeve （K-L） transform for decorrelation is very sensitive in practical implementations. We provide further insights on the sensitivity of K-L trans- form, which can be well exploited to develop an improved version of K-L transform for removing this sensitivity. With the improved K-L transform, some extra information should be sent over public channels, the amount of which can be well con- trolled so that the information revealed to the potential eavesdropper is minimized. Simulation results show that the proposed scheme can generate more secret bits with a low bit disagreement ratio. In the same time, we show that the key size generated per unit time can also be increased even with the simple CASCADE agreement protocol.