Revving up the 5G rollout at Three UK

Three's 5G rollout means expanding capacity on many fronts at the same time, explains network strategy and architecture manager Firoz Vohra

It's a basic a law of telecoms that as networks speed up people use more data. It happened with 3G, it happened with 4G and 4G+ and it's about to happen with 5G too. Projections based on Ofcom figures suggest that by 2025 UK mobile users will be getting through a massive 90 GB of data per month on average, compared with the single digits they use today, so a ten-fold increase in five years.

This has led to a rush for capacity from the mobile telecoms operators, who have been building new data centres, setting up new radio access networks (RANs), boosting backhaul fibre networks that carry signal from these facilities to the data centres, buying up 5G spectrum and generally upgrading their hardware and software infrastructure to ensure it's up to the increased load.

Three UK, already a network that attracts high-volume data users, has been doing all this, and more, said Firoz Vohra, network strategy and architecture manager at Three.

"Our aim is to become a big provider of fixed wireless broadband, offering landline-based broadband services but in a mobile fashion using 5G technologies," he said. "We've acquired a significant spectrum for 5G services, we've moved to sign in new agreements with radio access network providers to put in the new sites, and, we have signed new agreements to connect those sites with our network."

Three has also spent the last few years upgrading its core network, last year launching what it claims was the world's first 5G-ready core network in conjunction with Nokia, a SDN-based platform capable of being segmented into different virtual networks. The telecoms firm has also upgraded the back-office IT systems including the billing platform which have been moved to AWS, Google Cloud and Microsoft Azure clouds for enhanced availability and stability.

The rollout of Three 5G services began in February this year and is now available in 68 cities as the company continues to add capacity.

Many of these changes made in gearing up for 5G, including the virtualisation of the core network and moving the IT services to the cloud, were made easier by the fact that the network and the billing platform were decoupled from each other a decade ago via an intermediary service layer, a radical move at the time when billing platforms and data and voice networks tended to be tightly interconnected, a situation that led to differential scaling problems.

Decoupling the network infrastructure from the IT has helped Three to upgrade its IT and networking systems along parallel paths. By caching the network signals and only delivering to the billing systems the information required when it's needed, the integration layer has meant that the billing system did not need to expand in tandem with data growth, which Vohra says saved the company millions of pounds on upgrades no longer required.

It also solved the problem of ‘revenue leakage' when customers could not be charged for their usage when the billing system went down, something that was not infrequent in the pre-cloud days. The services layer was a key factor in Three's 2016 bid to acquire O2, a move that was squashed by the competition authorities.

This services layer, based on Tibco technologies, is being upgraded to Tibco's latest Streaming for 3GPP backbone which adds the capability to take streaming data events from the network and perform actions in accordance with 3GPP mobile broadband standards.

Working in conjunction with the core network SDN, this will bring a number of benefits, said Vohra, with an eye on the next two or three years.

"We are going to cut our networks into parts so that we can have a part of a network that is servicing a retail estate, a part of the network could be servicing machine to machine or IoT, a part of a network for fixed wireless access, a part for 3G and 4G, and so."

The integration layer will become an increasingly important ‘unified policy engine', orchestrating the rules governing these disparate virtual networks, he said.

"We see the streaming layer being the key in terms of making those decisions. And that covers the normal PCRF [Policy and Charging Rules Function] and also making policy decisions around creating the new networks. So how you expose and orchestrate a new complete new network for an MBNO and what business policies and rules you want to drive."

There are many other innovations that should be possible through decoupling and network decentralisation, he added, "but most of those are a bit further out right now"

So what's next?

The next few steps, Vohra said, will be bringing 5G "to more customers very quickly" at the same time continuing to build the capacity of the systems in anticipation of the growth in data throughput that will inevitably result from the higher speeds.

"They work in parallel, so you need to have the radio signals so customers can get the high speed, and then you need to scale up the internal core. Once that's done we'll be looking at more automation, a more programmatic approach to eliminate some of the manual processes."