5G technologies are early in their development, and the business cases for them are a bit fuzzy, but wireless researchers and executives still had plenty to celebrate this week at the annual Brooklyn 5G Summit. They’ve made steady progress on defining future 5G networks, and have sped up the schedule for the first phase of standards-based 5G deployments.
Now, the world is just three years away (or two, depending on who you ask) from its first 5G commercial service. Amid the jubilance, reality is also starting to set in.
While attendees can agree that 5G networks will incorporate many new technologies—including millimeter waves, massive MIMO, small cells, and beamforming—no one knows how all of it will work together, or what customers will do with the resulting flood of data. The video below provides a primer on these technologies, and a hint of what we can expect.
1. Update from AT&T
For the past year, AT&T has tested early 5G technologies at 4 gigahertz, 15 GHz, and 28 GHz from its labs in Austin, Texas. Like many of its competitors, the company is currently focused on fixed wireless, which means providing over-the-air broadband Internet service between two stationary points.
Already, the company has used high-frequency millimeter waves (roughly between 30 and 300 gigahertz) to provide superfast Internet service at speeds of 1.5 gigabits per second to one enterprise client. (Its service is broadcast at 28 GHz.)
Now, Dave Wolter, assistant vice president for radio technology and architecture, said AT&T plans to expand its fixed wireless trials to serve roughly 10 pilot customers in the Austin area this year. They'll be a mix of residential properties and small businesses.
For its enterprise trial, the company installed a transmitter on top of one of its buildings, with a clear line of sight to a receiver placed about 250 meters away on an upper floor of a client’s office building. The only problem was that the client’s office had double-coated windows, which are energy efficient but block millimeter waves. To make the trial work, AT&T had to switch out those windows for a single-coated variety.
Moving forward, Wolter expects 39 GHz become AT&T’s key frequency for fixed wireless, as well as for mobile devices. AT&T recently acquired Straight Path Communications, which had vast spectrum holdings for both 39 GHz and 28 GHz.
It’s still an open question of what customers will do with their upgraded service—and how much they will pay for it. When an audience member asked Wolter to name an application that he believes will justify the capital expenditure that AT&T must shell out for spectrum holdings and a 5G build-out, Wolter deferred.
“Good question, and I hope our business folks are working on that,” he said.
2. Massive MIMO
High-frequency millimeter waves have been all the rage in wireless circles for the past few years, and NYU Wireless led much of the early work that catapulted them to fame. But this year, the summit organizers devoted an entire session to massive MIMO, which seems to be having a bit of a moment.
There have been several big stories about massive MIMO since last year’s event, including new world records in spectral efficiency, the world’s first commercial trials, and early mobile trials. Facebook even got in the game with Project ARIES.
“In the past year, we’ve actually shown that [massive MIMO] works in reality,” said Ian Wong of National Instruments. “To me, the biggest development is that the skeptics are being quiet.”
Massive MIMO builds on a 4G technology known as multiple input, multiple output, or MIMO. This technology uses many antennas, combined with signal processing, to communicate with several users on the same frequency, at the same time. With it, carriers have added capacity to crowded frequency brands below 6 GHz, where most consumer electronics operate today.
The actual definition of massive MIMO was the subject of some debate during the session, but Fred Vook, an engineer at Nokia, describes it as the extension of traditional MIMO to a large number of controllable antennas. And by “a large number,” he means more than eight antennas, though some massive MIMO arrays have 100 or more.
Based on the day’s conversation, massive MIMO has solidified its place as a foundational 5G technology. “4G was the first system to start out with MIMO, and we expect 5G will be the first system to start right off the bat with massive MIMO,” declared Durga Malladi, a senior vice president at Qualcomm.
There’s certainly more work to be done (one of the stickier questions is how to integrate gobs of antennas into a smartphone) but the general outlook for massive MIMO now feels rather upbeat.
“I truly believe that there’s no other technology below 6 GHz that can give 5G gains, other than massive MIMO,” said Wong.
3. 5G New Radio
Earlier this year, a slew of companies petitioned 3GPP, a group that defines 5G standards, to speed up the schedule for describing 5G New Radio. This standard is important, because it will set the terms for the air interface by which base stations communicate with mobile devices, with the goal of improving performance and ensuring consistency across carriers and manufacturers.
Those companies were particularly interested in one type of 5G New Radio—what’s called non-standalone, as opposed to standalone. At the summit, Malladi of Qualcomm described the difference between the two like this: “In one mode, you rely upon 4G as an anchor, and in the other one, you deploy 5G without 4G as an anchor.”
The thinking is that a non-standalone 5G New Radio could be deployed more quickly, because it’s meant to be integrated into a 4G core network, whereas standalone 5G New Radio would operate on a brand new 5G core network (which is a much bigger undertaking to deploy and relies on even more standards).
In an afternoon panel, five executives confirmed their interest in developing non-standalone 5G New Radio as quickly as possible, and allowing the standalone version to lag behind. This suggests 5G will look and function a lot like 4G LTE in its early phases, before eventually migrating over to a spiffy new core.
In March, 3GPP accepted the accelerated schedule for non-standalone 5G New Radio, which should be defined by the end of this year. Some companies now expect to deploy their first standards-based 5G networks with it as early as 2019.
4. Will 5G live up to the hype?
Over the past few years, engineers and executives have set sky-high expectations for 5G. They’ve spoken of 5G as the wireless network that will unleash radical new technological advances in every possible realm, and promised that it will enable autonomous cars, streaming virtual reality, and remote surgeries.
Much of the talk at this year’s summit was as bold as ever. In a keynote about how 5G would improve industrial systems, Kenneth Budka of Nokia Bell Labs predicted that 5G technologies would “fundamentally transform human existence.”
This year, though, such grandiose statements were also punctuated with more sobering analyses. A generous helping came from Seizo Onoe, chief technology officer of NTT DOCOMO, who has developed something of a reputation for pouring cold water on 5G expectations.
During his keynote, Onoe said he has noticed an informal law during his time at DOCOMO: The wireless industry manages to achieve great leaps of success only in even-numbered generations. By his measure, 2G and 4G were truly transformational, while the improvements that came with 1G and 3G were mostly incremental.
“Applying this law to 5G, I would say we have to wait until 6G to fill all the expectations of 5G,” he said. Stay tuned.