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Understanding Open RAN

November 2020 – Chris Pearson, President, 5G Americas

Open Radio Access Networks (Open RAN) is one of the hot topics in the wireless cellular industry today. It involves the idea of interoperability of open hardware, software, and interfaces for cellular wireless networks. While the notion of open and interoperable networks may be simple at first blush, the underlying realities unpeel themselves like an onion – one layer at a time.

While there is momentum with many facets of Open RAN, the truth is that the Open RAN discussion is not quite so simple. In fact, one of the reasons we published our white paper on Transition Towards Open and Interoperable Networks” was to dive head first into the technical aspects of this important technology trend. Another reason we wrote this white paper was to get the industry all speaking the same language regarding this transition, because there are many misconceptions out there among even seasoned industry observers.  

Overall, our white paper sets the tone of the Open RAN solutions so that everyone understands where we are and perhaps where we are headed, introducing you to the various players and associations involved with its progress – from policy, to technical, to marketing work. This rich ecosystem of ideas is seemingly unlike so much of the bruising discord of today’s modern politics, as our industry is engaged in a healthy back-and-forth of impassioned viewpoints, varied experience, and tangible and intangible evidence.

Moderating an Open RAN conversation can be challenging

For perspective, let me talk about what this concept of Open RAN is, what it is not, and why it is important. Then I’ll address a few common Open RAN myths and misperceptions.

Again, Open RAN involves the interoperability of open hardware, software and interfaces and cellular wireless networks. The Open RAN concept introduces advanced features and capabilities beyond the current standard centralized approaches to the RAN through leveraging a programmable open-software development approach. Open RAN interfaces can allow for a “disaggregated” RAN into functional components such as a Radio Unit (RU), Distributed Unit (DU), Centralized Unit (CU) etc. to facilitate an open user plane, control plane, synchronization plane as well as management plane.

So why is Open RAN important?

Many wireless cellular companies are interested in Open RAN for the potential benefits it brings in terms of network management options, costs, and fostering a multi-vendor ecosystem of equipment suppliers. It can potentially provide additional flexibility to meet rigorous 5G application requirements in different vertical industries with varying network requirements for performance, capacity, and latency. Additionally, Open RAN might bring several additional benefits, including helping operators avoid “vendor lock-in”, introducing “best of breed” network solutions, possibly reducing the cost of network management, spurring innovation in the network, accelerating the time to market for network services, and integrating hardware and software development into network development.

Transition Towards Open and Interoperable Networks Figure 2‑10 Potential Benefits with Open RAN

However, the benefits might also come with some possible challenges. Wireless companies are trying to manage several issues, such as:  potentially increasing network latency, reliability and availability, new hardware/software requirements, complexity and automation issues, virtualization and security considerations, and interoperability among different network components.

Transition Towards Open and Interoperable Networks Figure 2‑11 Potential Challenges with Open RAN

For these reasons, network operators have varied timelines and interest in Open RAN as they each have a dynamic mix of strategies, business objectives, spectrum, technical architectures, network configurations, and deployed components. In fact, current networks have many deployment models, which can be distributed or centralized, non-virtualized, virtualized or cloud-enabled – all of which can have some Open RAN approaches applied to it. The figures below show how some major network operators have begun deploying elements of Open RAN.

This explosion of open RAN ideas has led to a sort of Renaissance of open RAN thinkers, each emphasizing their particular viewpoint on open networks.Indeed, today’s Open RAN ecosystem is quite active with multiple organizations including 3GPP, Cisco Multi-Vendor Open vRAN, O-RAN Alliance, Small Cell Forum, Telecom Infra project (TIP), and the recently formed Open RAN Policy Coalition. Each of these organizations represents a legitimate area of focus for the movement. It is the very nature of RAN openness and standardization that fosters this conversation and is enabling a multivendor ecosystem that allows innovation to thrive and potentially drive down 5G network operation costs.

Whatever each of these organizations can accomplish regarding Open RAN, it is clear artificial intelligence and machine learning will be being used to help manage modern wireless cellular networks. The manual human interventions required in 2G, 3G, and 4G networks cannot keep up with the scale and scope of what needs to be achieved in multiple spectrum bands with highly sliced and multiservice networks for 5G and beyond. Intelligence is becoming tightly interwoven with networks and is an important part of the open RAN landscape.

AI-enabled solutions hold the promise of managing this scale of complexity with capabilities such as auto-configuration, self-driving and self-healing networks that use new learning-based technologies to automate operational network functions and reduce OPEX. This new “intelligent” RAN should be able to sense its environmental and application context, as well as interpret and act on the contextual information in real-time extremely efficiently.

As AI and ML integrations become more sophisticated in open networks, they will need to seamlessly work with the underlying architecture. Use of interoperable open interfaces will allow them to perform data collection, and configuration changes for these tasks. Use of open APIs will implement algorithm clusters (such as rApps and xApps in RICs) to allow multiple solutions to be tried and tested for best results for the same use case.

As we proceed along the path to open RAN, it is important to keep in mind a few possible key myths and misperceptions. In a robust and active marketplace of ideas, Open RAN advocates and detractors can sometimes present their positions as truisms. It is important to understand this healthy debate, so that a constructive conversation can continue to take place.

Common Open RAN Myths

Myth 1 – Open RAN requires network virtualization.

This is false. Open RAN implementations can work in virtualized or non-virtualized types of environments.

 

Myth 2 – Open RAN automatically implies disaggregation of hardware and software.

 

Not necessarily. Operators have many options when it comes to their specific mix of radio unit (RU), distributed unit (DU) and centralized unit (CU). Some of that equipment may have network functions built into the hardware, while others may have disaggregated software/hardware functions.

Myth 3 – Open RAN is about keeping out specific vendors.

 

False. There are several specific stated benefits to the Open RAN movement, including lowering network management costs, accelerating innovation, etc.

Myth 4 – Open RAN requires a decentralized network

 

False. Open networks can work in either distributed or centralized types of network configurations.

Myth 5 – Open radio access networks are an inevitability.

Nothing is truly inevitable; however according to many third-party analysts Open RAN does have a lot of momentum.

 

Now that you have a good sense of what Open RAN is and isn’t, it becomes obvious there are many numerous nuances to this discussion. There is a rich tapestry of ideas and knowledge being woven here.  Transition Towards Open and Interoperable Networks” summarizes many of the key principles of these areas. When you have a healthy ecosystem of sprawling expertise, such as in the wireless cellular industry, new ideas burst forth easily and wireless consumers are all the better for it.

-Chris

For More Information

Un-peel the complexity behind Open RAN and look into the details at what operators and equipment manufacturers are thinking about when it comes to open and interoperable networks.

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