In this paper, we focus on the design of optimal relay and jammer selection strategy in relay-aided wireless networks. Different from previous works, assuming that the channel state information (CSI) of illegitimate nodes was available and only an eavesdropper existed, we first analyze disadvantages of joint relay and jammer selection (JRJS), average optimal relay selection (AORS), traditional maximum relay selection (TMRS) schemes. Then, we design an optimal relay and jammer selection strategy where the ratio of received SNRs at the destination generated by any two relays is maximized. By applying proposed strategy, computation complexity can be reduced. Moreover, we derive the lower and upper bounds of the secrecy outage probability based on the assumptions of existence of only illegitimate node and symmetric case for mathematical convenience. Finally, simulation shows that the proposed strategy operating with no CSI of illegitimate nodes can work efficiently compared with JRJS, TMRS and AORS strategies.

在本文中，我们专注于中继辅助无线网络中的最佳中继和干扰选择策略的设计。与以前的工作不同，假设非法节点的信道状态信息（CSI）可用并且仅存在一个窃听者，我们首先分析联合中继和干扰选择（JRJS），平均最佳中继选择（AORS），传统最大中继的缺点选择（TMRS）方案。然后，我们设计了一种最佳的中继器和干扰器选择策略，其中由任意两个中继器生成的目的地接收到的SNR的比率最大。通过应用提出的策略，可以降低计算复杂度。此外，出于数学上的便利，我们基于仅存在非法节点和对称情况的假设，得出了保密中断概率的上限和下限。