On the Secure Degrees of Freedom of Relaying With Half-Duplex Feedback
On the Secure Degrees of Freedom of Relaying With Half-Duplex Feedback
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DOI：
10.1109/tit.2010.2090250
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发表时间：
2011-01-01
影响因子：
2.5
通讯作者：
Poor, H. Vincent
中科院分区：
文献类型：
--
作者：
Kim, Tung T.;Poor, H. Vincent
研究了存在多天线窃听器的单中继系统上的安全通信协议。当源和目标之间没有直接连接时，允许目标和源同时干扰窃听者的放大转发（AF）协议显示，即使所有合法节点的天线严格少于窃听者，保密率也会随着发射功率（以dB为单位）线性增长。当目标天线的数量足够大时，可实现的安全自由度的数量被量化并显示匹配上界。但是，在源和目标之间存在直接链接时，此缩放规则不再适用。在存在直接源-目的链路的情况下，识别了AF方案的瓶颈，激励使用另一种AF方案和一种新的压缩转发协议，该协议可以使用不安全的反馈链路实现正数的安全自由度。
Secure communication protocols over a single-relay system in the presence of a multiple-antenna eavesdropper are investigated. When there is no direct link between the source and the destination, an amplify-and-forward (AF) protocol that allows both the destination and the source to jam the eavesdropper is shown to achieve secrecy rates that grow linearly with the transmit power in dB, even if all the legitimate nodes have strictly fewer antennas than the eavesdropper. The number of achievable secure degrees of freedom is quantified and shown to match an upper bound when the number of antennas at the destination is sufficiently large. However, in the presence of a direct link between source and destination, this scaling rule no longer applies. The bottleneck of the AF scheme in the presence of a direct source-destination link is identified, motivating the use of another AF scheme and a novel compress-and-forward protocol that can achieve a positive number of secure degrees of freedom using an insecure feedback link.