The realisation of an Ethernet-based fronthaul is a fundamental component for the construction of future 5G LTE networks with high flexibility. The use of existing networks for the fronthaul, i.e. the connection of the RRH (Remote Radio Heads) to the mobile-telecommunications base station, enables considerable savings in costs and time. The technology has already been extensively standardised under the designation eCPRI and will be utilised for the 5G LTE expansion of the networks.
Within the framework of the iCIRRUS research project (until the end of 2017), an Ethernet-based fronthaul was implemented and validated in an experimental setup.
A CPRI/Ethernet bridge was realised for the establishment of an Ethernet-based fronthaul link via a 100 Gbit Ethernet aggregator. The particular requirement was to transmit a time-continuous CPRI data stream over a packet-oriented Ethernet connection and to convert it back into a CPRI stream at the end with exact synchronization of clock frequency and time.
It could be demonstrated that the implemented technical solution fulfils the synchronisation requirements and can be operated loss-free over a long period of time.