Why 5G vRAN matters

To virtualize high capacity 5G RAN and be competitive with systems that use custom silicon is a challenge that many people — including me — thought would be tough to overcome. To process 100MHz of bandwidth, with 256QAM modulation, 16 layers and 64T64R massive MIMO, per sector is a major baseband engineering task. It is an industry achievement that these systems are deployed at scale in any form. To do this in a virtualized system, deployed on a commercial off-the-shelf server, is even harder.

We now know it can be done. Operators in several markets have shown it is possible to run commercial 5G virtualized RANs (vRANs) without compromising the user experience and while meeting critical radio KPIs. This is a RAN engineering success — a triumph even.

Yes, vRAN systems make compromises relative to baseband on custom silicon, notably in power consumption and physical footprint. And yes, the RAN developer must optimize software for the server platform. But it is now possible to deploy vRAN in high capacity 5G networks in a way that scales operationally to support high quality, reliable nationwide services.

But why does this matter? Why is vRAN important to 5G? And why should operators care?

In simple terms, vRAN and cloud RAN — the terms are quickly becoming interchangeable — bring a range of capabilities to operator networks that will emerge and evolve over the next decade. These include the following:

  • Cloud infrastructure and operations: Mobile RANs are deployed at large scale with efficient deployment and operational models developed over decades. Nevertheless, there is potential to leverage "cloud scale" infrastructure and automation tools to generate further efficiencies in RAN hardware and software operations. No question, there is work to do to support RAN workloads as cloud native applications, and cloud infrastructure still needs to be proven in terms of long-term support in the field, but this approach to RAN system integration, deployment and operation offers promise.
  • Edge architectures for service innovation: RAN processing and cloud compute exist on a continuum. By adopting cloud platforms, operators can more easily combine distributed and centralized RAN architectures in the same network. And by hosting RAN processing on common edge infrastructure with 5G core and end-user applications, there are opportunities to optimize the service experience. In this sense, cloud RAN can be an enabler for advanced services.
  • Programmable RAN and fast feature development: Cloud native RAN software (microservices, containerized, orchestrated) and CI/CD methodologies create opportunities for faster development cycles and faster deployment in the field. It makes it easier to evolve individual software modules in a non-disruptive manner — for example, to add new mobility management algorithms or RAN policies — and closely aligns with the programmable RAN model enabled by the O-RAN Alliance RAN Intelligent Controller (RIC) architecture.
  • Competition and innovation: Disaggregation of hardware and software creates opportunities for market entrants and specialization. Custom RAN silicon is a huge investment affordable only to the largest equipment suppliers. In a vRAN scenario, developers can leverage the commercial silicon and server ecosystem, enabling them to focus on software and features. This model attracts new players with new ideas and creates competition. High performance merchant RAN silicon is now also becoming available from diverse sources to give software-centric system developers more hardware options.
  • Multi-generation in a single platform: Virtualization will enable operators to maintain earlier generations of network technology — such as 2G — without the need for traditional hardware equipment. For example, operators can run 2G, 4G and 5G network software on a common off-the-shelf server to serve the subscriber base as it migrates over time.

The current system of RAN deployment and operation is excellent — 8 billion mobile device subscriptions worldwide* prove this. The motivation for cloud RAN is not to replace this model overnight, but to complement it and offer a development path that can help prepare operator networks for a more dynamic and diverse services environment. vRAN is a long-term play that will evolve over a decade or more.

*Omdia's World Cellular Information Series (WCIS) Data Dashboard

This blog is sponsored by Samsung Networks.

— Gabriel Brown, Senior Principal Analyst – Mobile Networks & 5G, Heavy Reading

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