In this work, we provide a framework analysis of dual-hop hybrid Millimeter Wave Radio Frequency (RF)/Free Space Optical (FSO) MIMO relaying system. The source is equipped with multiple antennas and employs conjugate beamforming while the destination consists of multiple apertures with selection combining. The system also consists of a relay operating at amplify-and-forward mode. The RF channels are subject to Nakagami-m fading while the optical links experience the Málaga distribution. In addition, we introduce the impairments to the relay and receiver. In fact, the relay is impaired by the High Power Amplifier (HPA) nonlinearities while the receiver suffers from the In phase and Quadrature Imbalance. Moreover, we assume two types of HPA nonlinearities impairments called Soft Envelope Limiter (SEL) and Traveling Wave Tube Amplifier (TWTA). Closed-forms of the outage probability, the bit error probability, and the ergodic capacity are derived. Capitalizing on these performances, we derive the high SNR asymptotes to unpack insightful metrics such as the diversity gain. We also address the impacts of some key factors on the system performance such as the impairments, the interferers, the number of antennas and apertures and the pointing errors, etc. Finally, the analytical expressions are confirmed by Monte Carlo simulation.

中文翻译：

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HPA 非线性和 IQ 不平衡对混合 RF/FSO 协作系统的联合影响


在这项工作中，我们提供了双跳混合毫米波射频 (RF)/自由空间光学 (FSO) MIMO 中继系统的框架分析。源配备多个天线并采用共轭波束成形，而目的地由具有选择组合的多个孔径组成。该系统还包括一个以放大转发模式运行的继电器。 RF 信道会受到 Nakagami-m 衰落的影响，而光链路会受到 Málaga 分布的影响。此外，我们还介绍了中继器和接收器的损伤。事实上，继电器会受到高功率放大器 (HPA) 非线性的影响，而接收器则会受到同相和正交不平衡的影响。此外，我们假设两种类型的 HPA 非线性损伤，称为软包络限制器 (SEL) 和行波管放大器 (TWTA)。导出了中断概率、误码概率和遍历容量的封闭形式。利用这些性能，我们推导出高 SNR 渐近线来解析多样性增益等有洞察力的指标。我们还讨论了一些关键因素对系统性能的影响，如损伤、干扰、天线和孔径的数量以及指向误差等。最后，通过蒙特卡罗仿真验证了解析表达式。