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 centralised 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. An Open Air Interface (OAI) software base station is utilised where the option 8 fronthaul interface requirements are evaluated and the operational performance assessed over an Ethernet based E-band (71-86GHz) mmWave point to point radio link. Experimental measurements highlight the potential of high capacity wireless transport solutions to meet basic requirements of Ethernet based fronthaul interfaces. Findings also emphasise however, that the anticipated jitter performance requirements of higher configuration massive MIMO radio units (RU) cannot be supported without exploitation of higher layer functional split transport interfaces or new wireless transport spectrum assets such as D-band (130-174.8GHz).