Due to the rapid development of satellite laser communication technology, free-space optical (FSO) links present a promising alternative to traditional radio frequency (RF) links. In this paper, taking the influence of weather factors into consideration, we investigate the performance of the hybrid FSO/RF links where the feeder link operates in the FSO band and the user link operates in the hybrid FSO/RF band. Specifically, the FSO feeder link is modeled by the gamma–gamma distribution in the presence of beam wander and pointing error, and the detection method adopts either the intensity modulation with direct intensity (IM/DD) or heterodyne detection. The RF user link is assumed to follow the shadowed Rician model. In addition, in order to improve the transmission rate of the link under the time-varying satellite–terrestrial channel, a rate adaptation scheme is proposed. The performance of the system under study is evaluated in terms of the outage probability, average bit error rate (BER), and average transmission rate. Our results provide some important insights, for example, (1) due to the constraints of the feeder link and weather factors, there is an upper limit on the outage performance and bit error rate of the hybrid link; (2) the adaptive transmission strategy can significantly improve the transmission rate of the link compared with traditional design.

中文翻译：

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具有速率自适应混合自由空间光学和射频链路的依赖天气的卫星地面网络的性能分析

由于卫星激光通信技术的快速发展，自由空间光（FSO）链路成为传统射频（RF）链路的有前景的替代方案。在本文中，考虑到天气因素的影响，我们研究了馈线链路工作在FSO频段、用户链路工作在混合FSO/RF频段的混合FSO/RF链路的性能。具体来说，FSO馈线链路通过存在光束漂移和指向误差的伽玛-伽玛分布进行建模，检测方法采用直接强度调制（IM/DD）或外差检测。假定 RF 用户链路遵循影子莱斯模型。另外，为了提高时变星地信道下的链路传输速率，提出了速率适配方案。所研究系统的性能根据中断概率、平均误码率 (BER) 和平均传输速率进行评估。我们的研究结果提供了一些重要的启示，例如，（1）由于馈线链路和天气因素的限制，混合链路的中断性能和误码率存在上限；(2)自适应传输策略与传统设计相比可以显着提高链路的传输速率。混合链路的中断性能和误码率有上限；(2)自适应传输策略与传统设计相比可以显着提高链路的传输速率。混合链路的中断性能和误码率有上限；(2)自适应传输策略与传统设计相比可以显着提高链路的传输速率。