This letter studies physical layer security of an outdated channel-state-information (oCSI) decode-and-forward (DaF) opportunistic-relay (OR) network under equal-correlated (equ.c.) Rayleigh fading with maximal ratio combining (MRC) deployment. By assuming that relays operate under equ.c. Rayleigh fading and wiretapper-Destination operate under exponential-correlated (exp.c.) Rayleigh fading, this work (i) derives an MRC output (MRCO) distribution of multivariate equ.c. Rayleigh fading, (ii) derives an MRCO distribution of bivariate exp.c. Rayleigh fading under oCSI conditions, and (iii) expresses the secrecy outage probability (SOP) in closed form. By considering oCSI severity, channel correlation among cooperative DaF ORs, Destination, wiretapper, and MRC deployment, this work's practicality can be significantly improved. Detailed discussions are given, in which the impact of several important parameters on the SOP is discussed. Monte Carlo simulation is shown to match theoretical predictions.

中文翻译：

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多变量相关瑞利衰落与 MRC 和应用到无线保密

这封信研究了过时的信道状态信息 (oCSI) 解码转发 (DaF) 机会中继 (OR) 网络在等相关 (equ.c.) 瑞利衰落与最大比率组合 (MRC) 下的物理层安全性) 部署。假设继电器在 eq.c 下运行。瑞利衰落和窃听目的地在指数相关 (exp.c.) 瑞利衰落下运行，这项工作 (i) 推导出多元方程的 MRC 输出 (MRCO) 分布。瑞利衰落，(ii) 推导出二元 exp.c 的 MRCO 分布。oCSI 条件下的瑞利衰落，以及 (iii) 以封闭形式表示保密中断概率 (SOP)。通过考虑 oCSI 严重性、协作 DaF OR 之间的信道相关性、目的地、窃听和 MRC 部署，可以显着提高这项工作的实用性。给出了详细的讨论，其中讨论了几个重要参数对 SOP 的影响。蒙特卡罗模拟显示与理论预测相匹配。