5G is going to be all about multi-gigabit-per-second speeds, support for the booming internet of things and ultra-low latency. But 5G isn’t here yet. That said, operators are embracing the evolution aspect of LTE, using technologies including massive MIMO, License Assisted Access and more to pave the way for 5G and its use cases by upgrading and adding network infrastructure that boosts capacity, makes more efficient use of spectrum and sets the stage for next-generation network services and applications. Ahead of planned standard-compliant 5G network launches in the late-2018-2019 timeframe, take a look at how U.S. service providers are getting ready.
Massive MIMO
On a Feb. 2 call, Sprint CEO Marcelo Claure and CTO John Saw discussed the carrier’s roadmap to delivering a mobile 5G service on the back of ongoing massive MIMO testing ahead of planned deployment on the live network later this year.
“When you look at our 2.5 [GHz] spectrum,” Claure said, “…that is the low-band of 5G. We’re not going to have the same propagation issues that our competitors are going to have. I could not be more excited. We can roll out 5G just basically by utilizing our towers and our small cells and the entire network plan we have.” Claure said Sprint is positioned to deliver the first mobile 5G network in the U.S. and “potentially in the world;” with that comment Claure also called out the possibility that a “Korean operator” may claim the world’s first designation.
CTO John Saw provided a little more color on the carrier’s path to 5G, noting that 128-element massive MIMO antennas, equipped with vertical and horizontal beamforming form the basis of that evolution. “Our path to 5G is going to be coming through massive MIMO,” Saw said. “Because of our strong spectrum position…we’re able to basically use half these antennas for LTE and simultaneously use the other half for 5G. Essentially you’re killing two birds with one stone. You can turn on 5G with a software upgrade in a few months.”
Saw said massive MIMO field trials, conducted last year with Ericsson and Samsung, would continue ahead of commercial activation later this year.
Verizon and Ericsson have been testing massive MIMO, which multiplies the number of antenna elements on either side of a radio link. In January, Nicola Palmer, Verizon chief network engineer and head of wireless networks, said, “Massive MIMO is a critical component of our 4G LTE advancements and will play an important role in 5G technology that will result in single digit latency and scalability in the billions of connections.”
Those tests involved a mobile test device using Qualcomm’s X20 LTE modem, which is part of the Snapdragon 845 platform, announced in December. Commercial smartphones that support massive MIMO and incorporate the 845 are expected in the first half of 2018 with potential debuts at Mobile World Congress.
LAA
In August 2017, Verizon conducted a “commercial network deployment” using Ericsson’s LAA-compatible Radio 2205 and a test device using Qualcomm’s Snapdragon 835 mobile platform and X16 modem. That collaborative work yielded a downlink throughput of 953 Mbps and prompted the carrier to begin deployment of LAA radios at small cell sites around the country. On the spectrum side, Verizon aggregated three unlicensed 5 GHz channels with one 20 megahertz channel of AWS spectrum.“ You’re going to see these pop up all across the country,” VP of Network Support Mike Haberman said at the time.
Noting “successful live LAA field trials,” AT&T Vice President, Ran and Device Design, Gordon Mansfield said, “This enhanced connectivity allows us to increase download speeds, expand network capacity and improve spectral efficiency in our network. People are consuming data at a rapidly increasing rate, and LAA will allow our consumers to do things like stream their favorite content on the go and experience virtual reality at faster speeds.” Building on those field trials and the demonstration, in November 2017 AT&T began commercial deployment of LAA in select areas of downtown Indianapolis, Indiana.
Mark McDiarmid, T-Mobile US vice president of network engineering, explained late last year that the operator would likely reach an installed base of 5,000 small cells by the end of 2017, and has 25,000 additional small cells contracted, “most of which will be done” in 2018, with LAA-compatible small cells turned up in the first quarter of 2018.
“These small cells are maybe a few 100 yards to maybe a quarter mile [apart] at most,” McDiramid said. “But when you take 40 [megahertz] of licensed spectrum and 60 [megahertz] of unlicensed spectrum…the capability and the capacity that you put in that small cell is quite dramatic. That’s one of the ways we’re going to deliver gigabit.”
NB-IoT
The internet of things (IoT) consists of a huge variety of use cases that come with a widely varying set of network capacity and coverage needs; support for massive IoT is also one of three primary 5G use cases. To address this large market, operators around the world are providing low-power, wide-area coverage with both LTE-based IoT networks and narrow-band IoT (NB-IoT) networks, which uses a 180 kilohertz channel to provide peak downlink throughput int he 50 Kbps range.
Verizon already offers LTE Cat M and Cat M1 services, and now, according to the company, it will deploy a nationwide NB-IoT guard band network throughout 2018. Narrowband-IoT can be deployed in-band within an LTE carrier, standalone or in the guard-band of an LTE network, which limits impact the LTE and doesn’t require any new spectrum. Verizon noted LTE Cat M 1 supports applications like “wearables, fleet and asset management, NB-IoT guard-band focuses on applications needing data rates below 100 Kbps.”
In October 2017 T-Mobile US launched an NB-IoT network, which was tested in Las Vegas as part of a smart city initiative. It’s planning a nationwide launch by “mid-year” 2018. The “Un-carrier” has emphasized the efficiency of NB-IoT along with the low cost in its announcement. “Because it can operate in guard bands – the network equivalent of driving down the shoulders on the highway — NB-IoT carries data with greater efficiency and performance and doesn’t compete with other data traffic for network resources,” the carrier said.
