Performance Analysis of Cell Free-Massive MIMO with Hybrid RF/FSO Fronthaul Links

In this paper, we analyze the performance of fronthaul communication links configured with hybrid radio frequency (RF) / free space optics (FSO) communication systems for a cell-free (CF) communication network. The fronthaul links are designed from access points (APs) to central processing unit (CPU) and selection combining (SC) is performed at CPU for the uplink data transmission. We derive the closed-form outage probability expression by considering Rician fading for the RF link and Gamma-Gamma fading for the FSO link. The closed-form expressions are validated with Monte Carlo simulation framework for a wide-range of use cases. Numerical results show the effectiveness of the considered hybrid RF-FSO communication links for fronthaul communications of CF communication systems.