This letter investigates the outage performance of an optical feeder link in satellite communications, where the gateway is equipped with multiple apertures and employs diversity combining schemes to mitigate the effect of atmosphere turbulence. In particular, by assuming that the optical link undergoes the Málaga fading, we first derive a closed-form expression for the outage probability (OP) of the considered system with selection combining (SC). Subsequently, when equal gain combining (EGC) is utilized, we present an approximate yet accurate probability density function expression for the sum of independent and identically distributed Málaga random variables. Next, we derive an OP expression for the considered system with EGC. To gain more insights, we further obtain diversity order for both SC and EGC schemes. It is found that the diversity order for both schemes is related to the number of receive apertures and the effective number of large-scale cells of the scattering process.

中文翻译：

---

具有分集组合的卫星通信中光馈线链路的中断性能

这封信调查了卫星通信中光馈线链路的中断性能，其中网关配备了多个孔径，并采用分集组合方案来减轻大气湍流的影响。特别是，假设光链路经历了马拉加衰落，我们首先通过选择组合（SC）得出所考虑系统的停电概率（OP）的闭式表达式。随后，当利用等增益合并（EGC）时，我们为独立且均匀分布的马拉加随机变量的总和提供了一个近似而准确的概率密度函数表达式。接下来，我们使用EGC导出所考虑系统的OP表达式。为了获得更多的见解，我们进一步获得了SC和EGC方案的分集顺序。