OpenRAN 101 Series

OpenRAN: Why, What, How, When

OpenRAN 101 Series

OpenRAN: Why, What, How, When

History

The entire telecom industry is going through a dramatic change that can be only compared to the change that data centers went through in the 2000s, all driven by Moore’s Law. This is driving the need to move from costly, proprietary RAN solutions to COTS and open, software-based ones, and to create a broader vendor supply chain.

Evolution of HW/SW Disaggregation

NOW in Telecom

Source: Parallel Wireless

The main takeaway here: Software is only as good as underlying hardware. Once there were COTS servers available to disaggregate the RAN, the Open RAN movement got its wind.

Why

Most of the CAPEX required to build a wireless network is related to the RAN segment, reaching as high as 80% of the total network cost. Any reduction in the RAN equipment cost will significantly help the bottom line of wireless operators as they struggle to cope with the challenges of ever-increasing mobile traffic and flat revenues. Forecasts show 5G deployment costs falling 30% between now and 2022 if a network is built in the traditional way, but those deployment costs could drop by 50% if an open architecture is used. MNOs are also realizing that opening up the RAN for only 5G will not reduce the overall network TCO. The operators believe that modernizing their legacy networks, in addition to deploying 5G, will reduce their overall network OPEX as they will have one unified network to run and will be able to make time and cost-saving remote upgrades to the overall site.

The concept of Open RAN goes beyond just standards interoperability. In theory, a RAN built by any of the legacy vendors is supposed to be interoperable with any device, any core, and any transmission network due to its conformance with 3GPP standards.

What

About 10 years ago, virtualization of the RAN started with the C-RAN (cloud RAN or centralized RAN) initiative from IBM, Intel and China Mobile. C-RAN resulted in a deployment model where a baseband unit that was doing digital processing could be located in a data center and not on the site itself...

Virtualized RAN (VRAN) versus OpenRAN

Source: Parallel Wireless

The point to emphasize here is that vRAN is not Open RAN as it still contains proprietary interfaces and purpose-built hardware. Open RAN is about defining and building 2G, 3G, 4G, and 5G RAN solutions based on general-purpose, vendor-neutral hardware and software-defined technology. The interface between the BBU and RRU/RRH is an open interface, so any vendor’s software can work on any open RRU/RRH.

Example Scenario: OpenRAN Deployment Model

SP/MNO could replace the OpenRAN software as easily as they did the hardware.

OpenRAN Software

OpenRAN Hardware from any ODM/OEM/RAN Vendor

Source: Parallel Wireless

How

...important to note that 3GPP considered the split concept (DU and CU) from the beginning for 5G. In a 5G cloud RAN architecture, the BBU functionality is split into two functional units...

1. Ability to use non-ideal fronthaul.
2. Ability to select any COTS-based BBU.

When

The Telecom Infra Project (TIP) was set up in early 2016 as MNOs were frustrated with a lack of innovation in a highly concentrated/closed ecosystem and high costs in the telecom equipment sector. The Open RAN TIP group has brought together operators, traditional equipment vendors and startups that are using open source technologies and open approaches.

In June 2018, Vodafone and Telefónica announced a joint RFI to evaluate RAN technologies that are software-based and that run on top of commoditized hardware...

The main takeaway: contrary to the information being published by legacy RAN vendors, Open RAN is real; Open RAN has been deployed in commercial networks today; the Open RAN community is thriving; the cost savings are being realized; and operational performance requirements and KPIs are being met.