At Mobile World Congress next week we’re going to hear a lot about 5G, that amorphous term for the next generation of cellular network technologies. But while the transformation to 5G is still years away, we’re going to see the first evidence of another more subtle transformation in Barcelona: the migration of the mobile network into the cloud.
In the halls of Fira Gran Via conference center, Alcatel-Lucent, Intel and China Mobile, the world’s largest mobile operator, will recreate a trial now live in China that virtualizes an LTE radio access network on a server. Why is that a big deal? It takes the most complex and expensive component of the cellular network, the base station, and tosses it into a data center.
Cellular systems are the very definition of specialized networks. Every cell site hosts enormous processing capabilities run on highly optimized hardware in order to convert analog radio fuzz into the ones and zeros our IP networks understand. A large mobile network like China Mobile’s can have hundreds of thousands of base stations. That’s a lot of processing power built into the network fringes.
By moving the base station from the cellsite and into a data center, a carrier no longer needs to build enough processing capacity into every cell to handle peak traffic conditions. Instead, it can allocate processing resources to the parts of the networks where it’s most needed at any given time. For instance, during evening rush hour, voice and data demand follows subscribers as they move out of a city’s central business district and into the neighborhoods and suburbs. A cloud radio access network (or Cloud-RAN) could simply follow commuters on their journey, transferring baseband capacity from one site to the next.
Carriers aren’t going to move their networks onto Amazon Web Services, but they would be able to build much simpler networks. A cell site simply becomes a radio, an antenna and a backhaul link to the data center. Future generations of mobile networks could just be software upgrades, not rip-and-replace overhauls. And instead of using highly-specialized base station gear, they could run their networks on racks of servers.
That’s where Intel comes in. It’s been working for years with China Mobile and mobile equipment makers to find a way of replacing the mobile network’s highly specialized digital signal processors with off-the-shelf Xeon and Atom chips. Moving to a server architecture not only means cheaper hardware, but it means more multipurpose hardware. Instead of installing a specialized box for every element of the network, all of those elements are virtualized in software on the same computing platform.
The round about path to carrier self-virtualization
Virtualization isn’t just Alcatel and Intel’s kick. All of the major infrastructure vendors from Cisco Systems and Juniper Networks to Ericsson and Nokia — along with baseband chipmakers like Freescale and Texas Instruments — are all pursuing software-defined networking in some form, and many of them will be promoting their work at MWC. But most of them have focused on virtualizing the network core and voice/SMS switching infrastructure, most of which is already centralized in their network data centers.
Alcatel-Lucent, Nokia and Intel have been particularly vocal in pursuing this idea of a virtualized radio network, and they still have plenty of doubters. Some carrier CTOs have told me they find the concept far-fetched and impossible to implement. For one thing, Cloud-RAN would take enormous amounts of low-latency backhaul capacity to move raw radio frequency information from the cell site to the data center.
Alcatel-Lucent VP of product market Manish Gulyani admitted that it will take several years before mobile carriers are ready to shut down their base stations, but he said the virtualization of the network is already starting to happen. It’s starting in the core and moving outwards, he said.
The Franco-American equipment vendor is already in trials with 20 carriers around the world, and its initial focus is on applications. We should see first commercial launches of cloud-based voice-over-LTE services next year, Gulyani said. In 2016, carriers will be ready to move the big honking signaling gateways onto software. And after that we’ll start to first implementation of a virtual radio network.
Even then, the base station’s journey into the cloud will be gradual. Carriers will start with a “split-processing” architecture where base stations do all of signal processing grunt work, while the data center performs the higher order baseband functions.
But at the turn of the decade when carriers are ready to build their next generation of mobile networks – those 5G technologies we keep hearing about – their networks may already be undergoing a transformation. Building a high-powered 5G network might not require cranes, and trucks and armies for field technicians. Instead it could just mean building a bunch of massive data centers.