Fronthaul

The fronthaul portion of a C-RAN (Cloud Radio Access Network) telecommunications architecture comprises the intermediate links between the centralized radio controllers and the radio heads (or masts) at the "edge" of a cellular network.{{Cite web|url=http://www.lightreading.com/what-the--bleep--is-fronthaul/a/d-id/707868|title = What the [Bleep] is Fronthaul?}} In recent years fronthaul is becoming more essential as 5G becomes more mainstream.{{Cite web |last=Aviv |first=Erez |title=E-band mmW for 5G fronthaul & midhaul – use cases on the rise |url=https://www.ceragon.com/blog/e-band-for-5g-fronthaul-midhaul |access-date=2022-05-30 |website=www.ceragon.com |language=en-us}}

In general it is coincident with the backhaul network, but subtly different. Technically in a C-RAN the backhaul data is only decoded from the fronthaul network at the centralised controllers, from where it is then transferred to the core network.

It comprises dedicated fibers carrying data in the CPRI or OBSAI format.[https://www.ufispace.com/company/blog/what-is-cran-the-evolution-from-dran-to-cran What is C-RAN? The Evolution From D-RAN to C-RAN] This fiber network is either owned or leased by the mobile network operator. In the UK for example BT Openreach owns a majority of the fiber network to radio masts. There are proposals to modify Ethernet to make it more suitable for the Fronthaul network.http://www.ieee1904.org/3/meeting_archive/2015/02/tf3_1502_ashwood_1a.pdf {{Bare URL PDF|date=March 2022}}

Recently, a novel wireless fronthaul solution has been proposed for ultra-dense small cell deployment where networked flying platforms (NFPs) such UAVs, drones, tethered balloon and high-altitude/medium-altitude/low-altitude platforms carrying FSO transceivers have been introduced as aerial hubs to aggregate the small cell traffic and offer connectivity to the core network.{{cite journal|last1=Alzenad|first1=M.|last2=Shakir|first2=M. Z.|last3=Yanikomeroglu|first3=H.|last4=Alouini|first4=M.-S.|title=FSO-based vertical backhaul/fronthaul framework for 5G+ wireless networks|journal=IEEE Communications|volume=56|number=1|pages=218–224|date=2018|doi=10.1109/MCOM.2017.1600735|arxiv=1607.01472|s2cid=16529007}}