5G network consists of the access network(AN), bearer network, and Core Network(CN). The access network is generally a radio access network (RAN), which is mainly composed of communication base stations. Unlike 4G technology, 5G is not made up of BBU(Base Band Unit)、RRU(Remote Radio Unit）or antenna; instead, it is reconfigured as the following three functional entities: CU (Centralized Unit, Distribute Unit), DU (Distribute Unit, Distribute Unit), and AAU(Active Antenna Unit, Distributed Unit). The original 4G RRU and antenna are combined into AAU, and the BBU is separated into CU and DU. The DU is embedded in the AAU, and one CU can be connected to multiple DUs.
The concept of WDM(meaning Wavelength Division Multiplexing) is to use multiple light sources operating at different wavelengths to transmit a few independent information streams simultaneously over the same optical fiber.
A primary difference between fronthaul and backhaul is the part of the network the technology is deployed on. Backhaul links the mobile network to the wired network, while fronthaul describes the network architecture that connects the remote cell sites to the BBU.
Intel offers solutions for the following use cases: • Fronthaul gateway (FHGW). The fronthaul network refers to the connection between centralized BBUs and geographically separated RRHs. Here, the accelerator provides a fronthaul interface and can offload complex I/O connectivity to the radio units.
Fronthaul is defined as the fiber-based connection in RAN infrastructure between the Baseband Unit (BBU) and Remote Radio Head (RRH). ... This has placed eCPRI fronthaul among the most important 5G technologies in operator surveys.
A baseband unit (BBU) is a unit that processes baseband in telecomm systems. ... A typical wireless telecom station consists of the baseband processing unit and the RF processing unit (remote radio unit - RRU). The baseband unit is placed in the equipment room and connected with RRU via optical fiber.
Fronthaul is defined as the fiber-based connection in RAN infrastructure between the Baseband Unit (BBU) and Remote Radio Unit (RRU). Fronthaul originated with LTE networks when operators first moved their radios closer to the antennas. This new link was established to supplement to the backhaul connection between the BBU and central network core.
With the rapid development of 3G, 4G wireless communication systems and FTTx, the consumption of optical fiber resources in access network becomes more and more serious. 5G intensive networking and deep coverage need to consume more access fiber resources. The lack of access fiber resources has attracted more and more attention from major operators at home and abroad. In order to save 5G optical fiber resources, Sintai Communication aims at 4G C-RAN and 5G fronthaul transmission, providing the best fronthaul bearing solution and a full range of optical forward access devices.
In the wireless fronthaul transmission, the BBU and the RRU adopt the passive wavelength division bearer mode. Based on the WDM technology, the backbone fiber can realize the remoteness of multiple base stations by only one core, which can greatly save fiber resources. It’s applicable to areas where fiber resources are tight or BBUs are deployed in a centralized way .
Sintai has also proposed the semi-active WDM solution for 5G fronthaul transmission. It is similar to passive WDM, network management monitoring and optical layer protection functions are added on the basis of maintaining end-to-end low passive WDM cost. DU side equipment is active with optical layer protection and automatic switching. Power failure of equipment only affects network management but does not affect service. No power for remote system with the ability of outdoor deployment. Passive mux/demux can be deployed together with AAU to handle single-station service, or can be deployed at optical intersection site to converge multi-station service
1. 5G Fronthaul
5G Fronthaul is defined as the fiber-based connection in C-RAN infrastructure between the Distribute Unit (DU) and Active Antenna Unit (AAU).
2. 5G Fronthaul Semi-active WDM system
Deploying the active equipment at Distribute Unit (DU) and passive equipment at Active Antenna Unit (AAU)..
3. 5G Fronthaul passive WDM system
Deploying the passive equipment at Distribute Unit (DU) and Active Antenna Unit (AAU).
Support for CPRI and eCPRI standards as well as 4G/5G hybrid networking.
High bandwidth with single-channel 25G rates, which can smoothly evolve to single-wavelength 50G in the future.
High density with 20 pairs of wavelengths on a single trunk fiber.
Bandwidth delivered by an exclusive single wavelength to ensure high transmission efficiency. Abundant bandwidth resources.
Colorless ONU technology allows flexible wavelength allocation and wavelength routing.
In the future, a colorless Small Form-Factor Pluggable (SFP) ONU can be directly inserted into the Active Antenna Unit (AAU) to increase the equipment integration density.
The Arrayed Waveguide Grating (AWG) incurs a power loss of about 5.5 dBm, which is lower than that of the optical splitter.