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Open RAN is a push for industry standards in the design of gear that’s used in the radio-access segment of telecom cellular networks and is particularly relevant to the buildout of 5G infrastructure.
Radio-access networks (RAN) serve to connect the base stations that transmit and receive traffic to from endpoints like cell phones and laptops and provide the link toward the carrier core network.
Without standards, wireless equipment vendors designing their RAN gear don’t have to consider whether it interoperates with gear made by other vendors.
As a result, in order to have a network that operates smoothly, telecom companies, and increasingly enterprises, are stuck dealing with one company and one company only when they want to deploy a licensed wireless network. This vendor lock-in tends to keep prices high because it limits competition among the equipment vendors for the individual RAN elements. It also limits flexibility in network design.
What is Open RAN?
Open RAN is a collaboration of equipment makers and telecoms in various working groups to solve this interoperability problem by creating standards. As long as equipment meets open RAN standards it should be compatible with gear made by any other vendor whose gear also meets the standards. Without having to rely on one vendor for all the equipment, carriers and enterprises have more opportunity to shop around for the best deal on each piece.
Open RAN standards would also be available to software developers that could readily write innovative features and services to respond quickly to users’ needs.
Virtualised network elements
The Open RAN architecture virtualises parts of the cellular network that are traditionally handled by specialised hardware and software. Time-sensitive functions like QoS management, handover control, and load balancing are handled by the RAN Intelligent Controller near-real time layer (RIC near-RT), while policy management and analytics take place in the RIC non-real time layer.
Similarly virtualised functionality for radio frequency and baseband processing are provided by the distributed unit (DU) and remote radio unit (RRU) layers.
These features are designed to provide the core functionality required for all cellular networks, while offering the opportunity to mix-and-match the actual hardware being used -- as long as the equipment is O-RAN compliant, it can interoperate with other O-RAN compliant devices.
Who’s working on Open RAN?
The O-RAN Alliance is the biggest group working on Open RAN and is supported by all of the major equipment vendors, so might claim to be the de facto standard. It has published RIC, DU, and RRU specifications.
The alliance has had to navigate political troubles. Nokia temporarily suspended technical work and funding for the group in the fall of 2021 amid concerns that the company could be sanctioned for working with Chinese firms on the U.S. government’s banned list. O-RAN rules changes ensured that the China-firms’ participation complied with U.S. law, but as long as sanctions remain in place, the possibility of further trouble can’t be ruled out.
The Telecom Infra Project has, with its TIP OpenRAN standard, has also finalised some specification requirements, and the Small Cell Foundation has published some specs. All the initiatives have roughly the same goals in mind.
How is Open RAN important to 5G?
Telecom companies have been bewailing high infrastructure costs for a long time, and the issue got a lot more serious with the rush to deploy 5G equipment, much of which has a shorter range than previous-generation mobile networks. As a result, 5G networks requires many more base stations in order to provide general coverage. That’s not going to be cheap, so the big telcos are eager to support any initiative that could lower their capex.
Open RAN and private 5G
Open RAN is a boon to enterprises interested in private 5G and LTE. One of the main stumbling blocks to wider adoption of private, licensed wireless networks is cost, and open RAN could change the equation enough to let more organisations consider such networks.
Estimates of the market size for private 5G/LTE generally concur that the sector is set for a sharp upturn over the next five years. A recent estimate from Juniper Research said that annual spending on private cellular networks will more than double to nearly $12 billion over the next two years, and the advent of open RAN could be a big part of that.
