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8 June 2021

Amazon AWS deploys its first Open RAN testing system at cloud edge

The wide range of new use cases being deployed already around the 5G network edge is driving demand for more sophisticated service validation and equipment testing capable of demonstrating adherence to stricter performance measures relating to latency, capacity and speed.  At the same time, the dearth of choice for RAN equipment occasioned by Huawei’s exclusion in many countries, is generating groundswell behind Open RAN to encourage new entrants to the field and this too calls for new testing products.

This is giving cloud providers an opportunity to take up residence at the edge to provide testing services, even for operators not otherwise using their infrastructure. Amazon AWS, with its analytics pedigree from various developments and acquisitions, is not surprisingly at the forefront of this trend, having just deployed the first Open RAN test service on AWS Managed Services (AMS) at the edge. The technology was provided by test company Viavi Solutions with its TeraVM O-CU Tester on AWS Outposts, the managed service extending AWS infrastructure, services, and tools to on-premises facilities, yielding a hybrid of cloud and data center.

Open RAN disaggregates networks so that operators or enterprises can select interoperable key components from different vendors. Primary components are of three types:

  • Radio units (RU) where signals modulated onto radio frequencies are transmitted, received, amplified and digitized.
  • Distributed units (DUs) that support virtualized baseband functions at Layers 1 and 2, that require near-real time processing – for this reason the DU is often fairly close to the RU and cell site, though in less demanding environments for latency it may be collocated with in the cloud with the third element, the centralized unit.
  • Centralized units (CU) run network processes for Layers 3 and above and can sit closer to the network core to transmit the digitized radio signal into and out of the network.

Open RAN makes the protocols and interfaces between these building blocks – fronthaul between the RU and CU, and midhaul between the CU and DU – open.

Within the architecture the CU is a critical resource as the first point in the uplink from end users, where large amounts of traffic converge and need to be handled efficiently to meet performance demands. The Open CU Tester, part of the TeraVM family of fully virtualized and cloud-enabled network and application test solutions, validates that the CU operates according to 3GPP specifications, as well as Open RAN C-plane (control plane) and U-plane (user plane) profiles. It also ensures the CU interoperates with other 5G and Open RAN network functions and components, while performing optimally under a range of complex mobile traffic profiles.

“Our major customers are embracing the power of the cloud and 5G, unleashing rich applications for consumers, businesses and cities,” said Ian Langley, general manager of the wireless business unit at Viavi. “We’re pleased to work alongside them to validate application performance at any point in the network and welcome the collaboration with AWS.”

One almost certain early customer of the AWS/Viavi package in the USA will be Dish Network. As one of the few truly greenfield 5G deployments, Dish had no legacy baggage and decided to become one of the first 5G networks to be hosted entirely in the cloud with AWS. The operator had earlier in 2020 decided to major on Open RAN for greater freedom of choice and anticipated cost savings later, having selected Fujitsu and Altiostar as providers of Open RAN based radio components for its 5G network.

The decision to migrate its entire telco network onto AWS has drawn praise and criticism in equal measure for Dish. On the plus side, it will contain costs and ensure scalability in the most comprehensive use of public cloud so far by a major operator. But for that reason, it has been slated for handing over too much control to a far more powerful party, with some even suggesting it is like mediaeval vassalage where property and protection are given in return for payment and fealty.

By this argument, it is even worse than depending on the Nordic duopoly for the RAN, but this criticism is slightly wide of the mark because there is still more choice in cloud with six genuinely global providers alongside other smaller more vertically oriented contenders (see separate item below).