Improving Wireless Physical Layer Security via Cooperating Relays
Improving Wireless Physical Layer Security via Cooperating Relays
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DOI：
10.1109/tsp.2009.2038412
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发表时间：
2010-03-01
影响因子：
5.4
通讯作者：
Poor, H. Vincent
中科院分区：
文献类型：
--
作者：
Dong, Lun;Han, Zhu;Poor, H. Vincent
无线通信的物理（PHY）层安全方法可以防止窃听无上层数据加密。但是，它们受到无线通道条件的阻碍：没有反馈，通常只有在源死亡通道优于源式驱动器通道时，它们通常是可行的。节点合作是克服这一挑战并提高安全无线通信的性能的一种手段。本文在一个或多个窃听者的存在下，借助多个合作接力，解决了一个源死亡对的安全通信。考虑了三个合作计划：解码和前向（DF），放大和前向（AF）和合作干扰（CJ）。对于这些方案，继电器传输了重新编码的无噪声消息信号的加权版本（对于DF），接收到的嘈杂源信号（对于AF）或常见的干扰信号（对于CJ）。提出了新的系统设计，包括确定继电器权重和发射功率的分配，最大化可实现的保密速率受到发射功率约束的可能性，或者最大程度地减少受到保密速率约束的发射功率。对于DF，在一个窃听器存在下，为中继权重得出了封闭形式的最佳解决方案。对于其他问题，由于难以获得最佳的继电器权重，因此将几个标准视为导致次优但简单的解决方案，即，在所有窃听器（对于DF和AF）（对于DF和AF）中的消息信号的完全无效，或完全无效的堵塞。在目的地（CJ）发出信号。基于设计的继电器权重，对于在有多个窃听者存在的情况下，对于CJ，在一个窃听器的情况下，以封闭形式获得了最佳功率分配；在所有其他情况下，最佳功率分配都是通过迭代算法获得的。对获得的保密率和传输功率结果的数值评估表明，所提出的设计可以显着提高安全无线通信的性能。
Physical (PHY) layer security approaches for wireless communications can prevent eavesdropping without upper layer data encryption. However, they are hampered by wireless channel conditions: absent feedback, they are typically feasible only when the source-destination channel is better than the source-eavesdropper channel. Node cooperation is a means to overcome this challenge and improve the performance of secure wireless communications. This paper addresses secure communications of one source-destination pair with the help of multiple cooperating relays in the presence of one or more eavesdroppers. Three cooperative schemes are considered: decode-and-forward (DF), amplify-and-forward (AF), and cooperative jamming (CJ). For these schemes, the relays transmit a weighted version of a reencoded noise-free message signal (for DF), a received noisy source signal (for AF), or a common jamming signal (for CJ). Novel system designs are proposed, consisting of the determination of relay weights and the allocation of transmit power, that maximize the achievable secrecy rate subject to a transmit power constraint, or, minimize the transmit power subject to a secrecy rate constraint. For DF in the presence of one eavesdropper, closed-form optimal solutions are derived for the relay weights. For other problems, since the optimal relay weights are difficult to obtain, several criteria are considered leading to suboptimal but simple solutions, i.e., the complete nulling of the message signals at all eavesdroppers (for DF and AF), or the complete nulling of jamming signal at the destination (for CJ). Based on the designed relay weights, for DF in the presence of multiple eavesdroppers, and for CJ in the presence of one eavesdropper, the optimal power allocation is obtained in closed-form; in all other cases the optimal power allocation is obtained via iterative algorithms. Numerical evaluation of the obtained secrecy rate and transmit power results show that the proposed design can significantly improve the performance of secure wireless communications.