The emerging technology of mixed radio frequency (RF)/free space optical (FSO) communications offers a great deal of merits in seamless channels and has potential for use in deep space exploration. In this article, a new paradigm with the dual-hop mixed RF/FSO system for the deep space communications link during a superior solar conjunction is proposed. The performance of this system, which is composed of an RF link between the Earth and a geosynchronous orbit relay satellite and an FSO link between the satellite and a deep space probe is evaluated for the first time to the best of our knowledge. An asymmetric environment is considered, where the RF link is subjected to Nakagami-m fading and the FSO link is assumed to follow an exponentiated Weibull distribution, which is induced by coronal turbulence. Under the assumption of amplify-and-forward relaying, we first derive the cumulative density function and the probability density function of this deep space mixed RF/FSO system. Thereafter, the closed-form expressions for the system performance—such as the end-to-end outage probability, the average bit error rate for the M-ary phase shift keying modulation scheme, and the channel ergodic capacity—are determined in terms of Meijer's G function. Numerical results are provided to validate our theoretical expressions. The results suggest that the performance of our proposed deep space mixed RF/FSO system is vulnerable to some key parameters, but it still outperforms its pure RF and FSO counterparts. Consequently, this study paves the way for constructing a future deep space communication network.

中文翻译：

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太阳闪烁效应下混合RF/FSO深空通信系统


新兴的混合射频（RF）/自由空间光学（FSO）通信技术在无缝信道方面具有很大的优点，并且具有在深空探索中使用的潜力。在本文中，提出了一种双跳混合 RF/FSO 系统的新范例，用于高级太阳合相期间的深空通信链路。据我们所知，该系统由地球与地球同步轨道中继卫星之间的射频链路以及卫星与深空探测器之间的 FSO 链路组成，其性能首次得到评估。考虑不对称环境，其中 RF 链路受到 Nakagami-m 衰落的影响，并且假设 FSO 链路遵循由日冕湍流引起的指数威布尔分布。在放大转发中继的假设下，我们首先推导了该深空混合RF/FSO系统的累积密度函数和概率密度函数。此后，系统性能的封闭式表达式（例如端到端中断概率、多相相移键控调制方案的平均误码率以及信道遍历容量）根据下式确定： Meijer 的 G 函数。提供数值结果来验证我们的理论表达式。结果表明，我们提出的深空混合 RF/FSO 系统的性能容易受到某些关键参数的影响，但它仍然优于纯 RF 和 FSO 系统。因此，这项研究为构建未来的深空通信网络铺平了道路。