Hybrid free space optical (FSO)/radio frequency (RF) systems have been proved to be reliable for high-data-rate wireless backhauls. In this article, we present a unified performance analysis of the hybrid FSO/RF transmission system which transmits identical data in both links and implements two popular diversity combining schemes, namely, selection combining (SC) and maximal ratio combining (MRC), in the receiver. Specially, for the FSO link, the Gamma-Gamma turbulence with pointing errors under heterodyne detection (HD) and intensity modulation/direction detection (IM/DD) is considered in our analysis while the general κ-μ shadowed fading which unifies popular RF fading models is employed for the analysis of the RF link. As a result, unified closed-form expressions of outage probabilities and average bit error rates for different modulation schemes are derived. A preliminary extension of the RF link to multi-input–multi-output (MIMO) transmission is also analyzed. Analytical and Monte Carlo simulation results are provided to characterize the performance of the hybrid FSO/RF link which is compared to the single FSO link and the single RF link. The agreement between the analytical and simulation results confirms the unification of various FSO channels and RF fading scenarios into a single closed-form expression.

中文翻译：

---

分集相结合的混合FSO/RF系统统一性能分析

混合自由空间光 (FSO)/射频 (RF) 系统已被证明对于高数据速率无线回程是可靠的。在本文中，我们对混合 FSO/RF 传输系统进行了统一的性能分析，该系统在两个链路中传输相同的数据并实现两种流行的分集合并方案，即选择合并 (SC) 和最大比合并 (MRC)，在接收者。特别地，对于 FSO 链路，我们的分析考虑了在外差检测 (HD) 和强度调制/方向检测 (IM/DD) 下具有指向误差的 Gamma-Gamma 湍流，而统一了流行的 RF 衰落的一般 κ-μ 阴影衰落模型用于分析射频链路。因此，导出了不同调制方案的中断概率和平均误码率的统一闭式表达式。还分析了对多输入多输出 (MIMO) 传输的射频链路的初步扩展。提供分析和蒙特卡罗仿真结果来表征混合 FSO/RF 链路的性能，并将其与单个 FSO 链路和单个 RF 链路进行比较。分析和仿真结果之间的一致性证实了各种 FSO 信道和 RF 衰落场景统一为一个封闭形式的表达式。提供分析和蒙特卡罗仿真结果来表征混合 FSO/RF 链路的性能，并将其与单个 FSO 链路和单个 RF 链路进行比较。分析和仿真结果之间的一致性证实了各种 FSO 信道和 RF 衰落场景统一为一个封闭形式的表达式。提供分析和蒙特卡罗仿真结果来表征混合 FSO/RF 链路的性能，并将其与单个 FSO 链路和单个 RF 链路进行比较。分析和仿真结果之间的一致性证实了各种 FSO 信道和 RF 衰落场景统一为一个封闭形式的表达式。