Performance Evaluation of Seamless 5G Outdoor RoFSO Transmission at 39 GHz

This letter presents results of an experimental measurement campaign involving the deployment of combined radio over the fiber and radio over free space optics (FSO) technology in the cloud-based fifth generation (5G) fronthaul network operating in the millimeter wave (mmW) area. For this purpose, we have used 10 km of optical fiber, 50 m long outdoor FSO link and 1 m long antenna seamless radio frequency transmission at 39 GHz. The results show excellent performance in terms of the phase noise and the signal-to-noise (SNR) ratio. The error vector magnitude performance depends on the modulation format and are below the standard limits for the 5G new radio signals, with 400 MHz QPSK and 64-QAM showing almost identical results for SNR of up to ~19 dB whereas 256-QAM signal offering the best spectral efficiency. Moreover, we investigate the received mmW signal deterioration due to the atmospheric conditions in the FSO channel.