Ergodic secrecy capacity of MRC/SC in single-input multiple-output wiretap systems with imperfect channel state information

在物理层中,本文研究了存在信道估计误差的最大比合并/选择合并的保密容量性能。在一个单输入多输出窃密信道中,信源向一个装备M根接收天线并采用最大比合并/选择合并技术处理多径信号的信宿发送保密信息。与此同时,一个窃密者装备N根接收天线并采用最大比合并/选择合并技术来提高窃密的成功率。我们分别推导了两种情况下遍历保密容量的精确和近似闭式表达式:(1)最大比合并带有信道估计误差;(2)选择合并带有信道延迟。此外,本文得到了高信噪比斜率和高信噪比功率补偿两个重要的参数,它们在高信噪比条件下决定了遍历保密容量。最后,本文通过仿真分析验证了所得到的闭式表达式的准确性。

This paper investigates the secrecy performance of maximal ratio combining （MRC） and selection combining （SC） with imperfect channel state information （CSI） in the physical layer. In a single-input multiple- output （SIMO） wiretap channel, a source transmits confidential messages to the destination equipped with M antennas using the MRC/SC scheme to process the received multiple signals. An eavesdropper equipped with N antennas also adopts the MRC/SC scheme to promote successful eavesdropping. We derive the exact and asymptotic closed-form expressions for the ergodic secrecy capacity （ESC） in two cases： （1） MRC with weighting errors, and （2） SC with outdated CSI. Moreover, two important indicators, namely high signal-to-noise ratio （SNR） slope and high SNR power offset, which govern ESC at the high SNR region, are derived. Finally, simulations are conducted to validate the accuracy of our proposed analytical models. Results indicate that ESC rises with the increase of the number of antennas and the received SNR at the destination, and fades with the increase of those at the eavesdropper. Another finding is that the high SNR slope is constant, while the high SNR power offset is correlated with the number of antennas at both the destination and the eavesdropper.