Using the distributions of bivariate exponential-correlated Nakagami-$m$, and Rician fading, this paper analyses opportunistic relay channel-state-information (CSI) outdatedness—written as “relay outdatedness” for brevity in this work—under two-degree-of-freedom (DoF) line-of-sight (LoS), and $n$-DoF non-line-of-sight (NLoS), utilising maximal-ratio-combining (MRC) deployment under Rayleigh fading environments. End-to-end system performance under NLoS outdated-CSI (oCSI) conditions are also examined. Under the proposed generalised-oCSI conditions, a conditional distribution of Rayleigh fading is first obtained, from which the corresponding distribution of Rayleigh fading under MRC deployment can be derived. Detailed discussions are given, from which MRC appears to outperform selection combining diversity under generalised-oCSI conditions. Trade-off between key parameters is identified, and explained. Monte Carlo simulation is given, which is shown to match the proposed theoretical findings.

中文翻译：

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MRC 部署下的中继过时

使用二元指数相关 Nakagami 的分布百万美元和 Rician 衰落，本文分析了在两自由度 (DoF) 视线 (LoS) 下的机会中继信道状态信息 (CSI) 过时性 - 在本工作中为简洁起见写作“中继过时性” ）， 和 $n$-DoF 非视距 (NLoS)，在瑞利衰落环境下利用最大比组合 (MRC) 部署。还检查了 NLoS 过时 CSI (oCSI) 条件下的端到端系统性能。在提出的广义oCSI条件下，首先获得瑞利衰落的条件分布，从中可以导出MRC部署下瑞利衰落的相应分布。给出了详细的讨论，从中 MRC 似乎在广义 oCSI 条件下优于选择组合多样性。确定并解释关键参数之间的权衡。给出了蒙特卡罗模拟，这表明与提出的理论结果相匹配。