OpenRAN for dummies.

“Open RAN is critical to Deutsche Telekom’s strategy to foster greater vendor diversity and accelerate customer focused innovation in the radio access network” underlines Claudia Nemat, Board Member, DT

"Open networks are undeniably the key to driving network evolution in the 5G era and to sustaining and fulfilling our mission of consistently delivering superior experiences to our consumer and enterprise customers," said Enrique Blanco, Chief Technology & Information Officer (CTIO) at Telefónica

Vodafone will use OpenRAN technology in 30% of its masts across Europe by 2030, Johan Wibergh, Vodafone Group Chief Technology Officer, said in a speech at Mobile World Congress (MWC) 2022 in Barcelona

Why are telecoms so hyped around OpenRAN? What's the fuzz around it? Why everybody is talking about it? Let's dive a bit in the deep waters of the telecom world and try to understand this important for the telecom industry and for our society trend.

A bit of history

In order to understand the concept and motivation of OpenRAN, we need to look at the early stages of the mobile networks. The architecture of the typical 2G network as designed back in 1991 has two main components - Base Station Subsystem (these are the cell towers, we see on top of buildings) and Network Subsystem (usually deployed in secure data center rooms and facilities). This concept is demonstrated on the picture below with some additional components like the mobile handset and external networks.

Each of these two subsystems, on its own consist of number of standalone boxes. To go into the details of each box will be beyond the idea of this article, but the important thing to understand is that these boxes were highly proprietary products. Their HW and SW are tightly integrated and proprietary solutions. Because of this proprietary nature, it was not possible to mix and match boxes from different supplier but the whole Base Station Subsystem or Network Subsystem had to be supplied by single vendor. This was especially true for the Base Station Subsystem (also called Radio Access Network (RAN)). That was not too bad at that time. There was not need for innovation the way it is needed today. The technology had to provide only one service, namely mobile telephony. Other aspects like - size, power consumption, speed of introduction of new services, automation, autonomous operations, elastic capacity and high speed requirements did not mater so much and even at all. However this approach soon become not efficient. First, operators started to realize that they quickly get locked by the vendors that supply their RAN boxes. A typical radio network consist of thousands and tens of thousands of boxes and is being deployed over multiple years. 70-80% of the CAPEX investment goes in the radio network. So the bargaining power of the supplier quickly raises as soon as a contract is signed. Everything that was not in the contract suddenly becomes extremely expensive. This, of course, extremely limits the capability for innovations on the operator side. The situation was not good for the suppliers as well. As the greenfield deployments began to diminish worldwide, in order to get new contract, suppliers had to "buy-out" the existing equipment from the operators and replace it with their own. Obviously this was very expensive and in order to break-even, suppliers had to further apply and expand the concept of "super charge if not in the contract". This is when operators invented a commercial model that I call "All You Can Eat" model. That is one flat monthly fee for all features available in the supplier's portfolio with only only pricing factor being the number of cells deployed. An approach very much similar to what we currently know as "subscription model" from Software as a Service world. This model however required totally new technology approach to build Radio Access Network.

So what is OpenRAN?

OpenRAN, or Open Radio Access Network, is a new approach to building mobile networks that replaces the traditional, proprietary hardware and software used in radio access networks with open, standardized and disaggregated components. This approach allows mobile network operators to mix and match components from different vendors, enabling greater flexibility, lower costs, and increased innovation. This is exactly the opposite of the traditional RAN networks which we discussed in the previous chapter.

OpenRAN promises to bring several benefits to operators and consumers alike, such as:

• Diversifying the supplier ecosystem: OpenRAN enables operators to avoid vendor lock-in and choose the best-of-breed solutions for their needs. This also creates more opportunities for new entrants and niche players to compete in the RAN market, fostering innovation and diversity.
• Lowering total cost of ownership: OpenRAN reduces the capital and operational expenses of deploying and maintaining RAN infrastructure by leveraging commoditized hardware, cloud-native software, and automation. OpenRAN also allows operators to optimize their network resources and performance according to different use cases and scenarios. Lowering entrance barrier for new suppliers increases the competitions and contributes to the reduced total cost of ownership.
• Improving network performance: OpenRAN enhances the quality and reliability of mobile services by unlocking capabilities that were not possible before like network slicing, edge computing, and artificial intelligence.
• Empowering customers: OpenRAN gives more choice and control to customers over their mobile experience by enabling them to access new features and applications, and benefit from lower prices and better quality.

OpenRAN is not a single technology or standard, but a collective vision of various industry stakeholders, such as operators, vendors, regulators, and research institutions. Several initiatives and organizations are working together to define and promote open RAN principles and specifications, such as the O-RAN Alliance, the Telecom Infra Project (TIP), and the Open RAN Policy Coalition.

While OpenRAN has the potential to transform the mobile industry, there are also challenges that need to be overcome. One of the biggest challenges is interoperability. With so many different components from different vendors, to make sure that everything works together seamlessly can be a challenge. The following picture is only a quick glimpse at the functional complexity of processing radio signals in RAN networks. As shown, there are 27 functional blocks and the vendors must have mutual agreement how the different components shall talk to each other so that operators can really mix and match components.

To make it easier for everybody, worldwide standardization bodies like 3GPP are working on establishing common industry standards to be followed by the vendors. Currently 3GPP has defined two well accepted split architectures - so called Option 2 and Option 7 (or 7.2). More on the pros and const of the different split architectures can be found in this nice article of RCWireless. For our simplified discussion we will only say that 3GPP defines three standard components of OpenRAN. They are simply called - Central Unit (CU), Distributed Unit (DU) and Radio Unit (RU) and often abbreviated like O-CU, O-DU and O-RU, with "O-" standing for Open. The O-RU are the antennas which we see on the top of the buildings while O-CU and O-DU are software components which can be physically found in different places of the network and in different topologies. While O-RU is really a component that is running on dedicated HW (this is basically the very last piece of HW that connects directly to the antenna), the other two are software modules that can run on virtual HW. This completely changes the game for the operators. Here is why. As we know from the IT world, virtual HW is much cheaper than the physical HW. It is managed like a SW - you can create and delete virtual HW in matter of minutes (not months). You can automate it and create/delete virtual HW as per actual capacity demands. The opportunities for operators using virtual HW are practically unlimited. e.g. operators can test different O-CU vendors by downloading trial versions just like we currently download trial SW of our favorite photo editor. Approach to reliability and fault management is also dramatically changed when using virtual HW. Because operators can deploy new virtual HW in matter of minutes and not days, if something goes wrong in their network, they can simply delete and redeploy the faulty virtual HW. This can be done even automatically. The complex network maintenance and operation processes can be eve fully automated and entrusted to AI systems trained for this. Such systems could be trained with knowledge of best network engineers, preserving this knowledge and making it available to the telecom operators even when their staff leaves or gets retired. This way operators can solve their attrition and employee scarcity problem.

Challenges for OpenRAN.

Of course like everything in life there are many challenges for OpenRAN and long way to go before this vision becomes reality. Interoperability is key aspect. The challenge arises from the fact that OpenRAN is still an emerging technology, and there may be differences in how different vendors and software developers approach the development of OpenRAN solutions. This can result in differences in the way that different OpenRAN components operate and communicate with each other.

The maturity of the whole OpenRAN ecosystems is another challenge. The OpenRAN ecosystem is still relatively new and not as mature as traditional RAN solutions. A typical challenge with a new ecosystem is that it may lack the necessary resources, support, and expertise to ensure the smooth operation of OpenRAN networks. For example, there may be limited support for integration with legacy networks. This could result in delays in deploying OpenRAN solutions, or increased costs associated with developing custom solutions.

The OpenRAN ecosystem is still evolving, and there may be differences in how different vendors and software developers approach the development of OpenRAN solutions. This can make it more challenging to ensure interoperability and consistency across different implementations of OpenRAN.

An OpenRAN network consist of much more components and options than traditional RAN. Operators have to make conscious choice for each component and each option. But before that, they need to build the expertise for that. E.g. here is how Telefonica designs their OpenRAN network (Telefónica views on the design, architecture, and technology of 4G/5G Open RAN networks - Telefónica (telefonica.com)) They need also to develop the internal skills to build and maintain OpenRAN networks.

Cyber security is another critical challenge around OpenRAN. As consumers, we are used to even not think about cyber security aspects when using our phones. With OpenRAN being massively implemented as software, the surface attack increases massively. every new disaggregation point is now potential back door for malicious actors. Every classic SW vulnerability issue (e.g. vulnerabilities associated with virtual HW) turns into potential threats for the OpenRAN network. The open nature of OpenRAN, which allows for the use of open source software and the sharing of interfaces and specifications, can make it more difficult to control the security of the network.

Despite these challenges, the opportunities presented by OpenRAN are too great to ignore. With the potential for greater flexibility, lower costs, and increased innovation, OpenRAN is poised to become the future of mobile networks.

Conclusion

OpenRAN represents a new approach to building mobile networks that is both disruptive and transformative. By replacing proprietary hardware and software with open, standardized components, OpenRAN enables greater flexibility, lower costs, and increased innovation. While there are challenges that need to be overcome, the opportunities presented by OpenRAN are too great to ignore. As our world becomes increasingly reliant on mobile connectivity, OpenRAN is poised to become the future of mobile networks. For the curious reader, here is list of some of the key vendors working in this space. you can explore their portals for more details on their OpenRAN approach.

1. Mavenir: A leading provider of end-to-end software-based networking solutions, including OpenRAN.
2. Altiostar: A pioneer in the OpenRAN space, offering virtualized RAN solutions.
3. NEC: A global technology company that has been a key player in OpenRAN standardization efforts.
4. Nokia: A major player in the telecom industry, Nokia has been actively developing OpenRAN solutions.
5. Parallel Wireless: A startup that provides OpenRAN solutions for both rural and urban networks.
6. Radisys: A provider of OpenRAN software and hardware solutions for mobile networks.
7. Samsung: A global technology company that has been developing OpenRAN solutions for both 4G and 5G networks.
8. Cisco: A provider of networking solutions, Cisco has been working on OpenRAN solutions for 5G networks.
9. Intel: A key player in the development of OpenRAN software and hardware components.
10. Qualcomm: A provider of mobile chipsets, Qualcomm has been working on OpenRAN solutions for 5G networks.

Here is also a list with some of the most advanced operators using OpenRAN technology.

1. Rakuten Mobile: Rakuten Mobile is a Japanese telecom operator that has made significant investments in OpenRAN technology. The company has built a fully virtualized, cloud-native mobile network using OpenRAN solutions, and has deployed OpenRAN solutions in more than 4,000 sites across Japan.
2. Vodafone: Vodafone has been a strong advocate for OpenRAN and has made significant investments in the technology. The company has deployed OpenRAN solutions in a number of countries, including the UK, Ireland, and Turkey, and is working to expand its use of OpenRAN across its global network.
3. Telefonica: Telefonica has been actively exploring the use of OpenRAN technology and has conducted a number of OpenRAN trials in various countries. The company has deployed OpenRAN solutions in Germany, and is working to expand its use of OpenRAN across its global network.
4. Deutsche Telekom: Deutsche Telekom has been investing in OpenRAN technology and has deployed OpenRAN solutions in a number of countries, including Germany and Poland. The company is also working to establish an OpenRAN testing and validation center in Europe.
5. MTN: MTN is a telecom operator that operates in multiple countries across Africa and the Middle East. The company has made significant investments in OpenRAN technology and has deployed OpenRAN solutions in a number of its markets.

Thanks for reading. Some parts of this article has been created with ChatGPT and other generative AI technologies.