NGFI, the xHaul

Traditional fronthaul (FH) solutions are not efficient and scalable enough to enable large-scale Cloud RAN deployment and to support 5G evolutions. In this paper we proposed a new fronthaul interface call Next Generation Fronthaul Interface (NGFI). The design principles of the NGFI are described including decoupling the FH bandwidth from the number of antennae, decoupling cell and user equipment processing and decoupling downlink/uplink processing. With NGFI, the FH networks could be developed based on packet-switched networks such as Ethernet. The realization of NGFI depends on two aspects: the function split between baseband unit and the remote radio units, and the underlined transport network design taking into account the new features of NGFI interface. In this paper the function partitioning principles are analyzed. In addition the major impact, challenges and potential solutions of Ethernet-based FH networks are also analyzed from jitter, latency, time and frequency synchronization perspectives.