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Innovation Briefing Issue 10 | Principles for Open RAN

  • 5 minute read
  • Published by Crispin Moller on 23 Aug 2022
  • Last modified 24 Aug 2022
Future networks need to be built with an understanding of the spirit Open RAN as well as the technical adherence. To this end DCMS has issued a guide to implementation. Simon Rockman has taken a look.

The Government has published a set of principles to help build a stronger telecoms supply chain. These are designed to inform the thinking behind organisations which are building and implementing Open RAN networks. Components in the networks of the future should be built to open, interchangeable standards and those components from a more diverse selection of suppliers.

The four key principles are open disaggregation, standards-based compliance, demonstratable interoperability, and implementation neutrality.

Underlying the principles is the ambition that the UK’s critical national infrastructure should not beholden to a small handful of suppliers. If the mobile network operators were to implement a network which was built to the full Open RAN standards, but were only to buy all the components from existing mainstream suppliers, then little would have been achieved. The policy goal is a thriving market of alternative suppliers.

Vendor Selection

While the idea of having lots of potential suppliers may seem attractive on the surface, particularly to operators, many of those implementing networks regard it as a complication. Two decades ago a good mix of companies provided network equipment, including such names as Nortel, Siemens, Motorola and Marconi. The mobile networks found it easier to deal with fewer companies, and in the end, just Ericsson, Nokia and Huawei were able to weather the vicious cost cutting and erosion of markets.

One of the problems of having multiple suppliers is that when two parts of a network don’t work with each other, it’s the mobile network operator which must then arbitrate between the two. Using something as standard as a router to connect to a base station means lot of configurations to ensure security: functions such as establishing a VPN or encryption. Standards for such functions are often implemented differently by different vendors. Choosing two suppliers therefore may create a lot more work. The two suppliers may claim that the other one is at fault. That is behind the push for more strict, standards-based compliance, and vendors being able to demonstrate interoperability with other vendors products and services. Products built to a standard, using well defined protocols, ought to be easier to install successfully.

The government does not define those protocols – that’s the job of the standards bodies such as ETSI and 3GPP. Choosing which ones to use has been part of the work undertaken by the Telecom Infra Project. Swapping parts from different vendors will require some testing and engineering to ensure optimal operation, but the adoption of standardised interfaces should ensure that vendors start from a much closer position: lowering the friction involved in swapping components by decreasing the cost of integration and interoperability testing.

One example of friction today is the continuing use of proprietary protocols.

Standards Variation

This is where demonstrating interoperability is important. While telecoms has many open, standardised interfaces they often do not specify enough detail, leaving implementations open to interpretation and to vendors including proprietary extensions. The only way to ensure that products are genuinely interoperable is to demonstrate them actually working successfully with other vendor products in realistic environments. It’s traditional to resolve this via a “plugfest” where manufacturers meet up with their equipment to test compatibility. Such events were very important in the early days of Bluetooth, making sure that particular mobile phones worked with particular car systems before the days of smartphones. This interoperability testing is undertaken by the O-RAN alliance – which runs Plug Fests to carry out OpenRAN interoperability testing. It has so far tested 77 scenarios across seven events across the world. In the UK, DCMS has funded SONIC Labs, run by Ofcom and Digital Catapult. These interoperability labs invite Open RAN suppliers to come and test their kit in a sandbox environment and build functional commercial relationships.

A mobile operator will be much more comfortable buying a piece of equipment from a new vendor if it has been shown to work reliably with the equipment that the vendor already owns. The DCMS Open RAN principles note that equipment which is deployed needs to be able to work with other vendors in reality, and is not just theoretically compliant with open standards. That level of assurance is needed between functional elements within each base station, between adjacent base stations, and between the base stations and the core and management networks that support the RAN. The guidelines note that “previous initiatives have succeeded in creating open interfaces, but failed to deliver multi-vendor interoperability because of proprietary management approaches.”

Over-standardisation runs the risk of stifling innovation and creating a market which differentiates only on price. The Principles look to implementation neutrality to counter this. The move to Open RAN and a more diverse supplier market won’t happen overnight, but a greater choice of suppliers should benefit the industry by lowering costs, while removing the reliance on a small number of companies that has been identified as a national security issue.

Principles in THE DCMS guidelines;

  • Open disaggregation.

This allows, and expects different elements of the RAN to be sourced from different equipment suppliers.

  • Standards-based compliance

Allowing all suppliers to test solutions against standards in an open, neutral environment.

  • Demonstrated interoperability

Ensuring that disaggregated elements work together as a fully functional system.

Implementation neutrality

Allow suppliers to differentiate  and innovate and on performance of

their products.

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