What is Open in Open RAN? And it’s Hardware

Dec 29, 2021

Moving from Closed RAN to Open RAN is a big leap for the telecom industry!

It is one of those that tests openness and disaggregation to its limits.

This is because it is an “end-to-end” openness in all RAN (Radio Access Network) layers. Notably, everyone knows that the interface between RU and DU is a closed and proprietary one in the wireless networks. And thus dominated by a few big vendors. Therefore, for any openness initiative that would be the first area to target.

However, O-RAN alliance, the responsible body for Open RAN, has set a bigger goal- Not just open the RU-DU interface but look at the end-to- end openness and disaggregation in all RAN layers that includes interfaces, hardware, software and separating RAN control plane from user plane.

So, what is this end-to-end open RAN network architecture and how it helps the mobile operators?

Openness and Open RAN hardware

We call it “Vertical” as well as “Horizontal” openness, as explained in the next section. As we explain this openness, we contend that the basic building block of this openness is the open hardware on which open software and open protocols live and thrive. Without the open hardware, therefore, the dream of total openness in Open RAN will remain elusive.

With this, we align with the O-RAN Alliance initiatives for Open RAN hardware. Their focus on Open hardware can be gauged by having a dedicated work group on white box under WG7. In fact, O-RAN Alliance has released multiple specifications under this initiative.

With this, let’s turn on understanding the “Vertical” and “Horizontal” openness in Open RAN.

 

Vertical Openness

Vertical Openness guarantees openness at the infrastructure and management layer, as shown in the diagram below.

  • At the lower most, is the open RAN hardware layer This is the infrastructure on which software runs. It can be any commodity hardware based on x86, commodity ASIC or FPGA. This layer is also called the “white box” layer and provides hardware independence and more hardware choices to the customers.
  • The Open RAN hardware hosts the Open Cloud layer. It runs containers and VMs that facilitate a variety of RAN virtual functions from multiple RAN software providers.
  • On the top is the open management layer. The controller and orchestration layer, including O-RAN RIC(s) like near-time-RIC and Non-real-time RIC can be sourced by any third party as they can interface through standard interfaces with the virtual functions.

Horizontal Openness

  • On the horizontal Openness, opening the most closed interface in the industry between RU and DU thus converting the closed Fronthaul to open Fronthaul. On the other hand, the interface between DU and CU is already open, thanks to F1 interface standardized by 3GPP.

All openness starts with open hardware.

A closed review of the different open components described about confirms our point of view. The open hardware or white box is the basic building block of all Open RAN components. The Open Cloud that hosts Open RU, Open DU and Open CU is built upon the white box, as well all the management components including the near-real-time RIC and Non-real-time RIC are hosted on open cloud as well.
 

Benefits of White Box for Open RAN

 

Lower Capex and resource pooling

It goes without saying, that it lowers the costs of network capex investment for mobile network operators to use white box because of economies of scale in this segment. Also, white box ensures resource pooling thus efficiently running the workloads at the optimum capacity.

Agility

A white box approach ensures greater network agility through support for a cloud-native architecture that supports software agility and innovation for communication service providers.

Simplification

White box facilitates keeping a few SKUs that translate into a few standard configurations making the operations simple and spare parts management much easier. For example, Rakuten Mobile network has less than 10 SKUs which makes their operations simple, agile and efficient.

In summary, white box is the future of the open networking and a part and parcel of the open RAN. Choosing the right white box hardware should therefore be a central part of any Open RAN strategy to be successful.
 

About Lanner White box for CU and DU

Lanner Electronics is a leading manufacturer of white box platforms for. It provides compact white box solutions and UCPEs for different network technologies and a wide variety of applications like Open RAN, MEC, NFV, SDN, network orchestration and S-WAN. Lanner’s ECA-4025   supports the dynamic and high performance throughputs for DU, while HTCA-E400 is a versatile platform that supports all in one carrier grade MEC applications and CU in one box.
 

References:

Cloud Architecture and Deployment Scenarios for O-RAN Virtualized RAN by (O-RAN) Doc RAN.WG6.CAD v02.02

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