Toward Wireless Fronthaul for Cloud RAN Architectures

The application of wireless backhaul is widely adopted in commercial mobile networks as a cost effective alternative to fibre. However, the practical use of wireless transport to support new cloud RAN architectures is not well studied. This paper presents proof-of-concept results which extend evolving Ethernet based mobile fronthaul concepts to wireless transport solutions. The theoretical performance criteria of the 3GPP option 8 functional split is derived and experimentally verified using an Open Air Interface (OAI) base station. Wireless fronthaul performance is assessed over an Ethernet-based E-band (71-86 GHz) mmWave radio link. Experimental measurements demonstrate the viability of existing mmWave wireless transport solutions to meet the performance requirements of the most challenging Ethernet based 3GPP option 8 fronthaul interface. Findings also suggest that further advances in standardisation of alternative functional split interfaces as well as higher capacity wireless transport spectrum such as D-band (130-174.8 GHz) could further support scalable cloud RAN deployments of the future.