RAN revolution with NGFI (xHaul) for 5G

From "Rethinking Ring and Young" in 2011 to proposing NGFI (xHaul) in 2014, the RAN revolutionary path to meet ambitious 5G demands has been charted out. Traditional fronthaul solutions fell short both in required bandwidth and architecture flexibility. Next generation fronthaul interface (NGFI, aka xHaul) proposed by China Mobile targeting a packet-based, traffic-dependent, and antenna scale-independent interface will be central to the 5G RAN revolution. This paper presents its latest progress. Specifically, a two-level NGFI architecture will be highlighted, and the function split options with associated requirements in, e.g. latency, bandwidth and synchronization will be presented. In addition, challenges for NGFI realization will be discussed.