This paper considered an energy-harvesting based secure two-way relay (EH-STWR) network, where two users exchanged information with the assistance of one buffer-aided relay that harvested energy from two users. To realize the confidential message exchange between two users in the presence of a potential eavesdropper, a secure bidirectional relaying scheme based on time division broadcast (TDBC) was proposed, where one user sent artificial noise to suppress the eavesdropper and another user transmitted data to the relay. A secure sum-rate maximization problem was formulated subject to average and peak transmit power constraints, data buffer and energy storage causality, and transmission mode constraints. By employing the Lyapunov optimization framework, a security-aware adaptive transmission scheme was proposed to jointly adapt transmission mode selection, power allocation, and security rate allocation according to channel/buffer/energy state information (CSI/BSI/ESI). Analysis results showed that the average achievable secrecy rate region can be significantly improved and there exists an inherent trade-off among transmission delay, requirement of transmit power consumption, and achievable secure sum-rate. Moreover, the channel condition between the energy-constrained relay and the potential eavesdropper is a critical factor on the achievable long-term average secrecy rate performance.

中文翻译：

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基于能量收集的安全双向缓冲辅助中继网络的可达到速率区域

本文考虑了一种基于能量收集的安全双向中继（EH-STWR）网络，其中两个用户在一个缓冲辅助中继的帮助下交换信息，该中继从两个用户收集能量。为了在存在潜在窃听者的情况下实现两个用户之间的机密消息交换，提出了一种基于时分广播（TDBC）的安全双向中继方案，其中一个用户发送了人工噪声来抑制窃听者，而另一个用户则向该用户传输数据。中继。针对平均和峰值发射功率约束，数据缓冲区和能量存储因果关系以及传输模式约束，提出了一个安全的总速率最大化问题。通过使用Lyapunov优化框架，提出了一种安全感知的自适应传输方案，可以根据信道/缓冲区/能量状态信息（CSI / BSI / ESI）共同调整传输模式选择，功率分配和安全速率分配。分析结果表明，平均可达到的保密率区域可以显着提高，并且在传输延迟，发射功率消耗的要求和可达到的安全总速率之间存在固有的权衡。此外，能量受限的继电器和潜在的窃听者之间的信道状况是可实现的长期平均保密率性能的关键因素。分析结果表明，平均可达到的保密率区域可以显着提高，并且在传输延迟，发射功率消耗的要求和可达到的安全总速率之间存在固有的权衡。此外，能量受限的继电器和潜在的窃听者之间的信道状况是可实现的长期平均保密率性能的关键因素。分析结果表明，平均可达到的保密率区域可以显着提高，并且在传输延迟，发射功率消耗的要求和可达到的安全总速率之间存在固有的权衡。此外，能量受限的继电器和潜在的窃听者之间的信道状况是可实现的长期平均保密率性能的关键因素。