Due to recent advances in laser satellite communications technology, free-space optical (FSO) links are presented as an ideal alternative to the conventional radio frequency (RF) feeder links of the geostationary satellite for next generation very high throughput satellite (VHTS) systems. In this paper, we investigate the performance of multibeam VHTS systems that account for nonlinear high power amplifiers at the transparent fixed gain satellite transponder. Specifically, we consider the forward link of such systems, where the RF user link is assumed to follow the shadowed Rician model and the FSO feeder link is modeled by the Gamma-Gamma distribution in the presence of beam wander and pointing errors where it operates under either the intensity modulation with direct detection or the heterodyne detection. Moreover, zero-forcing precoder is employed to mitigate the effect of inter-beam interference caused by the aggressive frequency reuse in the user link. The performance of the system under study is evaluated in terms of the outage probability, the average bit-error rate (BER), and the ergodic capacity that are derived in exact closed-forms in terms of the bivariate Meijer’s G function. Simple asymptotic results for the outage probability and the average BER are also obtained at high signal-to-noise ratio.

中文翻译：

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基于具有 HPA 非线性的 FSO 馈线链路的多波束超高吞吐量卫星系统的性能

由于激光卫星通信技术的最新进展，自由空间光 (FSO) 链路被认为是下一代超高吞吐​​量卫星 (VHTS) 系统对地静止卫星的传统射频 (RF) 馈线链路的理想替代方案。在本文中，我们研究了多波束 VHTS 系统的性能，该系统考虑了透明固定增益卫星转发器处的非线性高功率放大器。具体来说，我们考虑此类系统的前向链路，其中假设 RF 用户链路遵循阴影 Rician 模型，而 FSO 馈线链路在存在波束漂移和指向错误的情况下通过 Gamma-Gamma 分布建模直接检测或外差检测的强度调制。而且，迫零预编码器用于减轻由用户链路中的激进频率重用引起的波束间干扰的影响。所研究系统的性能根据中断概率、平均误码率 (BER) 和遍历容量进行评估，这些容量是根据二元 Meijer 的 G 函数以精确封闭形式导出的。中断概率和平均 BER 的简单渐近结果也是在高信噪比下获得的。