In this paper, we investigate opportunistic relaying and jamming techniques and develop relay selection algorithms that maximize the secrecy rate for multiuser buffer-aided relay networks. We develop an approach to maximize the secrecy rate of relay systems that does not require the channel state information (CSI) of the eavesdroppers. We also devise relaying and jamming function selection (RJFS) algorithms to select multiple relay nodes as well as multiple jamming nodes to assist the transmission. In the proposed RJFS algorithms inter-relay interference cancellation (IC) is taken into account. IC is first performed to improve the transmission rate to legitimate users and then inter-relay IC is applied to amplify the jamming signal to the eavesdroppers and enhance the secrecy rate. With the buffer-aided relays the jamming signal can be stored at the relay nodes and a buffer-aided RJFS (BF-RJFS) algorithm is proposed. Greedy RJFS and BF-RJFS algorithms are then developed for relay selection with reduced complexity. Simulation results show that the proposed RJFS and BF-RJFS algorithms can achieve a higher secrecy rate performance than previously reported techniques even in the absence of CSI of the eavesdroppers.

中文翻译：

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基于保密速率最大化的缓冲辅助中继系统的机会中继和干扰研究

在本文中，我们研究了机会中继和干扰技术，并开发了中继选择算法，以最大化多用户缓冲辅助中继网络的保密率。我们开发了一种方法来最大化中继系统的保密率，它不需要窃听者的信道状态信息 (CSI)。我们还设计了中继和干扰功能选择 (RJFS) 算法来选择多个中继节点以及多个干扰节点来辅助传输。在提出的 RJFS 算法中，考虑了中继间干扰消除 (IC)。首先进行IC提高对合法用户的传输速率，然后采用inter-relay IC放大对窃听者的干扰信号，提高保密率。使用缓冲辅助中继，干扰信号可以存储在中继节点，并提出了一种缓冲辅助 RJFS (BF-RJFS) 算法。然后，贪婪的 RJFS 和 BF-RJFS 算法被开发用于降低复杂性的中继选择。仿真结果表明，即使在窃听者没有 CSI 的情况下，所提出的 RJFS 和 BF-RJFS 算法也可以实现比以前报道的技术更高的保密率性能。