|
O-RAN Working Group 7’s deployment scenario specification shows thesplit architecture as below. The Fronthaul Gateway (FHGW) in this caseaggregates multiple O-RUs to a single location consisting of O-DUs. Thefronthaul gateway provides protocol translation, packet switching andaggregation capabilities.
The FHGW (Fronthaul Gateway) may be placed between the O-DU and RU(Radio Unit) with the following O-RAN specifiedinterfaces: • The interface between O-DU and FHGW isOpen Fronthaul (Option 7-2x). • The interface between FHGW and RU is anLLS option specified by O-RAN. • The interface between FHGW and RU may notsupport Open Fronthaul (Option 7-2x).
The Low PHY function in the fronthaulgateway converts the CPRI/low level split interface between the RU and Open Fronthaul (Option 7-2x). The fronthaul gateway isdeployed near the RU physically and gets connected to the DU using a packet-basednetwork.
The FHGW gateway has radio processingcapabilities to do the protocol translation between CPRI/low level splitinterface and Open Fronthaul(Option 7-2x) and does the translation for the management plane also. The non-O-RAN-RU along with FHGW appears as a single/multiple O-RU(s) to the O-DU.
The RUs and O-RUs are directly connectedto the FHGW. The O-DUs are connected to FHGW over a network. The network between FHGW and O-DU could be apoint-to-point, mesh or a ring topology. In some cases, the FHGWs provide transport tonon-fronthaul traffic also, namely, midhaul, backhaul or other traffic. So FHGW may have non-fronthaul ethernet interfaces also.
LOW PHY TheLow PHY module in fronthaul gateway implements the below functionalities. 1) FFT/IFFT (Lower-PHY DL/UL) 2) PRACH detection (Lower-PHY UL) 3) Handling of C-Plane/M-plane messages 4) Timing and synchronization of RU 5) eCPRI framing/de-framing and switching 6) CPRI framing/de-framing and switching 7) CPRI to eCPRI conversion 8) I/Q compression on eCPRI and CPRI links Doing LowPHY functionality on the FHGWsand converting the low-level split interface to O-RAN fronthaul interface enables connecting legacy RUs to O-DUs. Thisenables brownfield deployments to leverage thebenefits of O-RAN based disaggregated and open networks
硬件架构：
硬件组成：
Memory: The network processing unit in the FHGWhandles different types of traffic, terminates Ethernet connections, and interfaces with the radiosignal processing unit in order to transport data between the O-DU and legacy RUs following protocol translation in radio signalprocessor. The example reference design uses an NPU with thefollowing capabilities.
Radio signal processor implements theprotocol conversion between the split option 8 (CPRI) protocols used by legacy RUs and Open Fronthaul O-RAN7-2xinterface (eCPRI). The functions are hosted and processed in the radio signal processor, which in this example design is anFPGA: 1) FFT/IFFT (Lower-PHY DL/UL) 2) PRACH detection (Lower-PHY UL) 3) Handling of C-Plane/M-plane messages 4) Timing and synchronization of RU 5) eCPRI framing/de-framing and switching 6) CPRI framing/de-framing and switching 7) CPRI to eCPRI conversion 8) I/Q compression on eCPRI and CPRI links
| 
发表于 2025-4-21 11:18:38