YOU ARE AT:5GSprint's CTO talks massive MIMO, imminent 5G launch

Sprint’s CTO talks massive MIMO, imminent 5G launch

Sprint’s massive MIMO network is already on-air in its initial nine launch cities and carrying LTE traffic, and 5G service via the same sites will be officially launched before the end of the first half — in some cases, launches are just weeks away, according to Sprint CTO John Saw. And the carrier is doing AT&T’s “5GE” icon one better: one of its first 5G phones, the LG V50, will have a flashing 5G icon on the back of the phone in Sprint’s signature yellow, so that users can “show off at a street corner,” as Saw put it, and the people around them will be able to see that the device is operating on Sprint 5G.

The company is using its initial 5G deployments to address LTE network congestion in urban markets, Saw said, adding that “we have purposely gone in there and made sure that we have substantial 5G coverage, so you can see a 5G icon for more than just a few seconds and you don’t lose it.”

Saw, speaking at this week’s Brooklyn 5G Summit, said all that Sprint is waiting on is a stable, commercial-grade version of the network software it needs with all the bugs worked out, and then it is “good to go” for its 5G launch.

Sprint’s first markets include Atlanta, Georgia; Chicago, Illinois; Dallas and Houston, Texas; Kansas City; Los Angeles, California; New York City; Phoenix, Arizona and Washington, D.C. Of those, Chicago, Atlanta, Dallas and Kansas City are anticipated to launch in May, with the others going live later in the first half. Sprint first gave a detailed look at its expected 5G coverage footprint at Mobile World Congress in Barcelona, with more than 100 square miles of coverage expected in several markets.

Saw said that the company has hundreds of massive multiple-input multiple-output sites covering areas such as Manhattan, and that its testing has shown that with three-dimensional beamforming, it can cover a 50-story building with a single massive MIMO site.

“You cannot do that with a legacy antenna,” he said. Sprint is using 128-element massive MIMO equipment, which Saw said are more “neat and compact” than traditional cellular base stations, due in part to less cabling.

Sprint’s deep spectrum holdings at 2.5 GHz spectrum in the top 100 markets means that the operator can operate its massive MIMO sites in split-mode, with 60 gigahertz of spectrum each dedicated to LTE and 5G New Radio, Saw said. Sprint also has testing underway for intra-band carrier aggregation at Band 41, Saw added, and for inter-band carrier aggregation it will combine 2.5 GHz spectrum with its 1.9 GHz spectrum.

Sprint’s TDD spectrum offers it a unique advantage for leveraging massive multiple-input multiple-output, Saw noted — and the company doesn’t have to wait for 5G devices to penetrate its customer base to offer an improved customer experience.

“All the phones that support 2.5 GHz in Band 41 will benefit, the first time you turn on massive MIMO,” Saw said. “You cannot say the same for FDD [spectrum].”

As far as the possibilities that 5G opens up, Saw mused about the advances and disruption that LTE has enabled and how much more 5G will be able to support.

“Companies like Apple, Facebook and Uber took their business up a whole new level when they went mobile-first,” Saw said. “Now think about, who is going to be the next Uber, in a 5G world?” Disruption to healthcare, industry and other verticals is the promise of 5G, Saw continued, although he added that “we are a long way from realizing all the dreams of 5G. But we have to start somewhere.”

ABOUT AUTHOR

Kelly Hill
Kelly Hill
Kelly reports on network test and measurement, as well as the use of big data and analytics. She first covered the wireless industry for RCR Wireless News in 2005, focusing on carriers and mobile virtual network operators, then took a few years’ hiatus and returned to RCR Wireless News to write about heterogeneous networks and network infrastructure. Kelly is an Ohio native with a masters degree in journalism from the University of California, Berkeley, where she focused on science writing and multimedia. She has written for the San Francisco Chronicle, The Oregonian and The Canton Repository. Follow her on Twitter: @khillrcr