RoF/FSO-based Fronthaul for 5G Systems and Beyond

The next generation technologies claim for a radio access network (RAN) review in order to support the enormous upcoming wireless data traffic. Among the potential optical technologies, free space optics (FSO) represents a key element to achieve free-space data transmission according to the future technologies requirements, mainly due to its cost-effective, easy deployment, high bandwidth available and high security. In this context, we experimentally evaluated a hybrid architecture for fifth-generation of mobile networks (5G) and beyond. Such architecture employs radio over fiber (RoF) in a 1 km optical link followed by a 20 m FSO link as fronthaul. An M-QAM signal with 10 MHz bandwidth at 700 MHz was transmitted, for enabling long-range wireless applications. The performance of the RoF/FSO hybrid system was evaluated in terms of root mean square error vector magnitude (EVM
RMS
) and as a function of the optical power at the photodetector input. The hybrid RoF/FSO link reaches 60 Mbit/s throughput with EVM
RMS
values in accordance to 3
^rd
Generation Partnership Project (3GPP) Release 15 specifications.