Free space optical (FSO) communication has emerged to provide line of sight connectivity and higher throughput over unlicensed optical spectrums. Cognitive radio (CR), on the other hand, can utilize the radio frequency (RF) spectrum and allow a secondary user (SU) to share the same spectrum with the primary user (PU) as long as the SU does not impose interference on the PU. Owing to the potential of these emerging technologies, to provide full spectrum efficiency, this paper focuses on the mixed CR RF-FSO transmission scheme, where RF communication is employed at one hop followed by the FSO transmission on the other hop in a dual-hop decode-and-forward (DF) configuration. To quantify the performance of the proposed scheme, closed form error probability is derived over Rayleigh/Exponentiated Weibull (EW) fading distributions by considering the statistical and instantaneous feedback channel of the primary network. We also employed an asymptotic analysis to illustrate the diversity gain of the overall system. We believe that the proposed scheme can be applicable to the 5G+ networks where an unlicensed university student connects to the home computer with the aid of an FSO path.

中文翻译：

---

具有主次干扰的瑞利/EW衰落信道上认知RF-FSO中继网络的错误概率

自由空间光 (FSO) 通信已经出现，可在未经许可的光谱上提供视线连接和更高的吞吐量。另一方面，认知无线电 (CR) 可以利用射频 (RF) 频谱并允许次要用户 (SU) 与主要用户 (PU) 共享相同的频谱，只要 SU 不对PU。由于这些新兴技术的潜力，为了提供全频谱效率，本文重点介绍混合 CR RF-FSO 传输方案，其中在双跳中的一跳使用 RF 通信，然后在另一跳使用 FSO 传输解码转发 (DF) 配置。为了量化所提议方案的性能，通过考虑主网络的统计和瞬时反馈信道，在瑞利/指数威布尔 (EW) 衰落分布上推导出闭合形式错误概率。我们还采用渐近分析来说明整个系统的多样性增益。我们相信所提出的方案可以适用于无执照大学生借助 FSO 路径连接到家庭计算机的 5G+ 网络。