Mobile connectivity has powered an app revolution on smartphones and the Internet of Things for consumers and industry — but the mobile networks that deliver that connectivity are complex, proprietary legacy systems that are slow to develop and update.
For mobile operators and telecoms networks, opening up the radio access network — through emerging 5G mobile networks — is a chance to take advantage of the cost savings, virtualization, automation and interoperability that storage, networking and compute stacks have already achieved by switching from monolithic proprietary hardware to modular, software-driven approaches using off-the-shelf commercial servers.
Fundamentally, Open RAN is a giant step forward. It uses an open, software-driven architecture to put a generic compute layer into the special-purpose telecoms stack, which means operators will be able to automate and upgrade networks more easily, roll out new technology faster and offer the kind of services that make 5G more than just a faster mobile phone network.
Getting the Names Straight
The idea of Open RAN is that instead of cramming everything into the limited space and power available at a cell tower or base station, you split the mobile base station into some well-defined parts that communicate over open, defined interfaces.
That means you can strip the mobile base station down to just the antenna that receives and transmits the radio signal (plus a power source) with the compute to process those radio signals done on off-the-shelf hardware, maybe even in a nearby data center or in the cloud.
That makes the hardware easier to maintain and manage, and to scale up when you have more traffic. Operators can just allocate more processing power instead of trucking in temporary base stations to erect at festivals and sporting events when a location that’s usually almost empty suddenly has thousands of users and devices watching videos and uploading images,
With more space and power, it’s cheaper to offer edge computing services that you want to run as close as possible to the source of data for low latency and fast response. Open RAN may also allow operators to deploy new generations of mobile networks on existing hardware rather than having to roll out new systems each time.
Plus, 5G and 6G depend on having enough base stations to provide coverage and deliver hardware bandwidth and low latency: if Open RAN can create smaller, lower power base stations that can be deployed in more locations, it might speed up network rollouts.
But talking about Open RAN quickly gets confusing because as well as the general concept of the technology, it can also refer to some specific specification and groups. Unless you’re actually building and running a telco network you won’t usually need to know the difference and they’re sometimes used interchangeably, but getting it clear can make it easier to understand what a particular product, service or network is likely to deliver.
RAN stands for Radio Access Network; it’s the base stations and other infrastructure that delivers the “Air Interface” that connects phones, IoT devices and anything else that gets a cellular signal to the core network, with access to services delivered by the operator — and internet connectivity to use online apps and services.
O-RAN refers to the O-RAN Alliance (and that sometimes gets shortened to ORAN): an industry forum of vendors, mobile operators and researchers aiming to push the RAN industry towards “more intelligent, open, virtualized and fully interoperable mobile networks”.
Open RAN, which can confusingly also be shorted to ORAN, refers to the open specifications for RAN architectures published by the O-RAN Alliance (and it’s often used as shorthand for the general idea of these more open networks).
The point of these open specifications is to create interoperable building blocks. “If we don’t build every building block unique for every different service provider, there’s a gain here,” Jack Murray, co-chair of the O-RAN Software Community technical oversight committee, told us. “As we can agree on reusing more code, more APIs, more toolkits, more agreement where the networks touch each other we get exchange points, which become very valuable and enable growth and opportunity.”
This also takes advantage of the way open source unlocks community innovation. “What’s nice about open source projects is the community keeps adapting as the needs grow and bring more functionality based on what people need,” he noted.
That’s why the O-RAN SC is a joint project from the O-RAN Alliance and the Linux Foundation, focusing on the open source projects like ONAP, Anuket, Magma and others that deliver a lot of the Open RAN concepts — although there are also some projects with FRAND-licensed IP in the community and Open RAN implementations can include proprietary code for specialized functions.
OpenRAN (without a space in the middle) means the OpenRAN Telcom Infra Project, a group of operators and vendors working on the implementation of interoperable products from multiple hardware and software vendors with the goal of making telecom infrastructure more affordable in order to reach more of the world’s population — using the open RAN standards defined by O-RAN in the ORAN framework.
VRAN or Virtualized RAN, refers to taking the networking and data processing baseband processing functions that used to be implemented in proprietary hardware (usually using ASICs for performance and efficiency), rewriting them as software and virtualizing them on standard server hardware. As with cloud, separating the data and control plane means you can scale them independently, and move functions that aren’t real time or very sensitive to latency into centralized servers where you can increase utilization.
Cloud RAN (C-RAN) is a VRAN that’s designed to be cloud native so it can take advantage of microservices, containers, continuous delivery and other familiar DevOps techniques. That would let network operators take advantage of common cloud patterns like offering canary deployment to a certain percentage of users to test the new version of a service.
A VRAN is one of the ways you can implement the standardized, open interfaces between the different components of the RAN that ORAN describes — but VRAN doesn’t have to be open or multivendor, and Open RAN doesn’t have to be virtualized.
“VRAN is about making the RAN much more software-defined and programmable and shifting functionality from hardware to software,” analyst Richard Webb of research firm CCS Insight explained to the New Stack.
VRANs and C-RANs focus on disaggregating the network; Open RAN is about interoperability, with a set of standards focused on open networking that define profiles and interfaces for accessing functionality inside the RAN. Think of the interfaces as APIs between the different parts of the RAN and the outside world.
That means apps and services can use information that used to be locked inside the proprietary network stack, either to make the network work better or to take better advantage of the network.
The Benefits of Open RAN
Network operators like the idea that moving away from proprietary stacks from a single vendor to an open ecosystem where they can mix and match components creates a competitive environment.
But just focusing on the potential for reducing prices misses the point, Webb warned: “Open RAN is really about the diversity of functionality in the RAN. It should mean you’re engendering a more flexible, highly available network.”
Breaking the RAN up into disaggregated, software-defined pieces means you can put more features from different suppliers in the network, including smaller players with expertise in specific areas.
As well as the open interfaces, the big piece Open RAN brings compared to vRAN is a RAN Intelligent Controller (RIC) that can make the system smarter and far more automated by using the data that was previously locked inside the RAN for analytics. Not only can operators choose a RIC from a different vendor from the rest of the base station: the RIC itself may let them pick different functionality from something like an app store.
The first thing the network data will be used for is enhancing the performance of the RAN itself in near-real-time, improving spectral efficiency and reliability.
“RANs are complicated environments,” Murray pointed out. “If you’re close to the cell, far [away] from the cell, overlapping cells… With multiple spectrum, now that we can hand off different users into different bands, the management is becoming much more complex.”
There are multiple spectrum bands to take into account for different flavors of 3G, 4G, 5G and (in future) 6G, plus other networks to interoperate with like Wi-Fi 6E and 7 (plus LoraWAN, Zigbee and Z-Wave in some scenarios). There might be interference, congestion or an increase in different parts of the network. With 5G, radio resources will be assigned and reassigned from millisecond to millisecond.
With 5G, operators can deliver multiple virtualized, isolated logical networks on the same physical network infrastructure: one for gamers who need low latency and high bandwidth alongside a network for regular phone users and another for IoT devices where low power is more important. They might also want to prioritize some users, like hospitals, schools and first responders who need guaranteed quality of service.
This network slicing makes it easier to support the specialized needs of different groups of users, who care about different network characteristics (and are often looking for very different price plans).
“If you can tune the network, it’s better for the user and for the provider, because we’re matching the right resources to the right group of needs, rather than treating a remote sensor that has a very low duty cycle like a phone,” Murray said.
Operators can use the real-time information on RAN resource utilization to create and maintain those network slices “powered by AI-based algorithms used for traffic routing, location prediction, channel quality prediction and user selection,” Cristina Rodriguez, vice president of Intel’s Network & Edge group, told us.
You need a lot of data about what’s happening in the network to manage so dynamic a network and do more granular traffic management, but you also have to handle that data efficiently, Murray warns, “because otherwise, your network becomes all about the data and not about the service that you’re providing.”
Some RIC workloads don’t need to be so close to real-time and Open RAN can give network tooling access to data without having to move large amounts of data around. “With the disaggregated architecture where we now have a distributed near-real-time direct RIC versus a non-real-time RIC, you can put analytics close to where the data is generated and not have to move the data as far.”
Open RAN for Developers
Implementing the dynamic network relies on automation, another cloud native concept that’s new to the operator world where the networks aren’t just proprietary but heavily customized and updates are slow, complex and scheduled many months or even years in advance.
Open RAN promises remote automated software installation, zero-touch provisioning, test and validation, rolling updates and upgrades using CI/CD pipelines, and ultimately, self-healing and self-optimizing networks using telemetry, analytics and other AIOps features, with many solutions relying on the Kubernetes ecosystem for configuration and orchestration.
A lot of that automation and intelligence will come from machine learning, Rodriguez suggested. “A cloud native, software-based RAN architecture [like Open RAN] is ideal for integrating AI and machine learning, which allows operators to automate operational tasks in their networks to make them more power, resource and cost-efficient.”
Operators can then use that intelligence to offer extra services and SLAs to enterprise and high-end consumers in ways they couldn’t with 4G, she suggested. “Organizations such as media providers, factories, retailers, healthcare systems, and smart cities can benefit from guaranteed throughput, latency, reliability and increased quality of experience.”
“An automated factory assembling car parts requires ultra-reliable, low-latency communications to ensure that it meets production targets without costly downtime. With AI-powered networks, operators can bolster delivery of performance-related SLAs and sell that as a service to the manufacturer.”
But developers can also use the RIC data themselves, Webb noted. “When you’ve got that RIC, which is predicated on disaggregated software functionality, then you’ve got a stable platform for third-party apps to get access to network functionality, and then do their thing. App developers want access to that connectivity; they need that network to access edge computing, to access AI and other functions and the network is the route to that.”
In the past, network operators tried to compete with cloud providers by offering their own services or encouraging app developers to create apps specifically for their network but have usually failed because they don’t have the scale or the skills.
This time, Webb said, operators want to create a rich sandpit where app developers can leverage network assets (and use cloud technologies to work with them) to create network-intelligent apps that can use information from the mobile network.
“They want their network to be at scale, high capacity, ultra-low latency, but also a foundational platform for access to edge computing and processing power, to AI and machine learning and other capabilities that 5G and other network technologies will connect them to. And then they step back and said, OK developers, we’ve given you this playground, go play.”
Near-real-time response, guaranteed reliability and privacy will be important for industry applications like robotics and autonomous vehicles as well as manufacturing automation and quality assurance, and for safety applications like smart highways as well as AR and VR.
Smart cities will need the massive machine-to-machine communications of low-power sensors and IoT devices, as will pipeline monitoring. Not only will Open RAN make it easier to deliver basic connectivity to a stadium or racetrack when it’s packed with fans, but it will also let the network offer enhanced mobile broadband with the higher data rates that VR and video streaming need.
Apps and services may be very specific to different industries, Webb suggested. “The healthcare app development community will be able to leverage that connectivity and access to functionality to create apps that healthcare cares about, and the same for smart manufacturing or smart city sectors. It’s about that specialization and those vertical markets having enough access to both the technology and the scale of networking to make them rich environments for the specialist communities to develop what those specialist markets require.”
Imagine a parking lot that used the compute possible with Open RAN to update self-driving cars with the specific details they need to park efficiently on that specific lot without needing to communicate with every other car trying to park there at the same time. That’s more convenience for drivers, and more business for the parking lot operator, since you can fit in about twice as many cars if they’re self-parking.
Or you could digitize and entire road using information from cameras and sensors to create a digital twin that lets you treat it as an API that apps can call or infrastructure can use to adapt in real-time to the current situation. Custom object recognition models can use camera feeds to find safety hazards like debris on the road or vehicles that have broken down: which could trigger the lane to get closed and update warning signs.
Ferrovial is building a smart road system using Azure Public MEC services with a Kubernetes cluster deployed on Azure Arc to do that with both public and private 5G networks; the first roads will open in Virginia and Texas this year.
With Open RAN that compute can have the lowest possible latency, so the lane closure happens in time to avoid an accident and the system can provide other real-time services like dynamic traffic management or in-road charging for electric vehicles.
Barriers to Open RAN
Open RAN has a lot of benefits, but it’s also a major change in how operator networks are designed, built and maintained. Telco networks are complex, demanding, real-time environments where low latency and reliability are crucial.
The move to 5G means new architectures that bring an opportunity for a more disaggregated RAN but the quality, efficiency, reliability and resiliency have to match what you can get from proprietary, integrated RAN stacks, Murray warns. “Spectrum is a critical resource that costs a lot of money and a lot of the stack is about optimizing spectral efficiency. You have a very large user base that’s very demanding.”
“People rely on these networks: cars rely on them, safety personnel rely on them. It’s very hard to turn things off and migrate everything going forward.”
Some networks have already deployed Open RAN commercially at greenfield sites where they don’t have to deal with interoperability with legacy systems or in rural areas with less network traffic (so RAN performance isn’t as critical).
Many more have made commitments to using it in a significant proportion of their network, including those looking for alternatives to Huawei, for example in the UK where the vendor is banned from the 5G telecoms network and the government wants a third of mobile network traffic to be carries over Open RAN by 2030. Dish is running Open RAN and 5G Core software on Amazon Web Services (plus AWS Outposts in its own network) to build a new 5G network far more quickly than usual.
But Open RAN covers a large number of specifications and not all operators are implementing all of the interfaces or including the RIC. That might be because of the cost and complexity of integrating Open RAN into existing networks, concerns about a more complex architecture where they may not have the right skills and can’t turn to a single vendor for support, or the lack of edge data centers with fiber connections to cell towers for moving compute out of the base station. Reference designs, blueprints and integration testing will help, as will the speed at which hyperscale cloud vendors and hosters are rolling out edge compute. But there are also questions of maturity — the RIC is what really differentiates Open RAN but is still very basic in many cases — and hardware performance.
Existing commodity hardware may not always be suitable for Open RAN and as many RAN network functions have only recently been virtualized they aren’t always optimized and can take up most of the cores in a commodity server that operators are hoping to offer as a compute platform. Arm, Intel, Qualcomm, Marvell, Xilinx and other silicon vendors are building new chipsets and accelerators to deliver both the performance and low power consumption that traditional, physical RAN gets by using specialized chipsets like ASICs.
The hardware situation is better than it was 12 months ago, Webb suggested. “Intel and the like have had to respond to the sheer scale and workload and processing requirements for [servers] that are going to be in telco environments, versus say an enterprise environment because the deluge of data that’s going over those networks is an order of magnitude bigger.”
“They’ve had to roll their sleeves up and say ‘we need to think bigger in terms of what we’re offering to operators for their network processing requirements if they’re going to virtualize their networks.’”
Network virtualization is a hard problem. AT&T — which is perhaps furthest along with some three-quarters of its core network functions virtualized — decided in 2021 to move its 5G core software to Azure, in exchange for Microsoft buying and running its Network Cloud platform that the AT&T 5G core network runs on.
Open RAN will require even more infrastructure, automation, development and cloud native expertise that is rare in telecommunications whose know-how lies in other areas. It’s worth network operators making the effort to gain the skills for this new approach because they may need the applications and services Open RAN can enable by providing a distributed edge compute option within the network to truly deliver the promise of 5G and 6G.
But Open RAN is also important for the private LTE and 5G networks larger organizations are building for their warehouses, manufacturing plants and other locations where they need more flexibility than a wired network but with lower latency than Wi-Fi can offer.
“If a factory wants to go smarter and untether its production robots and connect them via 5g so they can be moved around different parts of the production floor, Wi-Fi can’t handle that kind of capacity and mobility,” Webb explained. That requires not just connectivity but AI and other processing that depends on the kind of low latency edge compute Open RAN can deliver in the network.
The pre-integrated solutions and appliances that familiar vendors like HP and Intel are offering for Open RAN with 5G specialists like Rakuten and familiar enterprise network partners like Juniper, often in conjunction with cloud providers like Azure and AWS, will work well here to simplify network integration, while still giving developers access to the low-latency edge compute platform Open RAN promises. Mobile operators are starting to create Open RAN-based small cell appliances that can connect to their network or a private 5G network.
There are around a thousand private LTE networks globally (and perhaps another 300 on 5G) but that could increase tenfold in the next few years. In fact, he suggested, private networks and small cell deployments might prove to be “the backdoor through which Open RAN goes mainstream for operators because they see it being so successful in those specialized enterprises and industrial environments”.
AWS and The Linux Foundation are sponsors of The New Stack.
Feature image: Vodafone explains how Open RAN is different from current Radio Access Networks.