fronthaul
In telecom, fronthaul is the connectivity between the radio unit and the distributed unit. Or, more formally, it describes the segment of the network that connects the remote radio heads (RRHs) at cell sites to the more centralized baseband units (BBUs). This connection is typically fiber-based and is a critical component of the Cloud Radio Access Network (C-RAN) architecture, which is increasingly being adopted in modern cellular networks, including 5G.
In a C-RAN setup, the BBU performs baseband processing and is centralized to serve multiple RRHs, which are located at the cell sites. The RRHs handle the radio frequency functions and are connected to the antennas. The fronthaul network enables the transport of signals between these two types of equipment. This architecture allows for more efficient management of resources and can lead to improved network performance, including higher data rates and lower latency, which are essential for advanced applications in 5G networks[1][2][3].
Fronthaul is distinct from backhaul, which refers to the part of the network that connects the mobile network (including the BBUs) to the wider wired network, such as the internet or a proprietary enterprise network. While backhaul can be wireless or wired, fronthaul is predominantly fiber-based due to the high bandwidth and low latency requirements[1][2].
The evolution of fronthaul has been driven by the need for greater bandwidth and lower latency in mobile networks. Technologies such as enhanced Common Public Radio Interface (eCPRI), Passive Optical Networks (PONs), and Wavelength-Division Multiplexing (WDM) have been developed to improve the efficiency of fronthaul fiber links. These technologies help to standardize the split architecture inherent in 5G fronthaul components, decrease data rate demands, and enhance the capacity of fronthaul networks[1][2].
With the advent of 5G, fronthaul has become even more critical due to the network’s support for enhanced mobile broadband (eMBB), ultra-reliable low-latency communications (uRLLC), and massive machine-type communication (mMTC) for the Internet of Things (IoT). The flexibility of fronthaul configurations is essential for balancing the latency, throughput, and reliability demands of these advanced applications[1][2].
In summary, fronthaul is a key component of modern mobile network infrastructure, enabling high-performance connectivity between centralized BBUs and distributed RRHs, which is essential for delivering the advanced capabilities promised by 5G technology.
Citations:
[1] https://www.techtarget.com/searchmobilecomputing/definition/fronthaul
[2] https://www.viavisolutions.com/en-us/fronthaul
[3] https://en.wikipedia.org/wiki/Fronthaul
[4] https://youtube.com/watch?v=JqtMZSLapJI
[5] https://www.radiall.com/insights/what-is-fronthaul-in-telecom
[6] https://scmedu.org/fronthaul/
[7] https://www.ciena.com/insights/articles/Primer-Mobile-backhaul-vs-mobile-fronthaul_prx.html