The CTOs of T-Mobile US and Sprint poured scorn on rival AT&T’s plan to push ahead with a mobile 5G launch in late 2018 before compatible handsets are available.

In separate briefings during Mobile World Congress, T-Mobile’s Neville Ray and Sprint’s John Saw said their companies preferred to wait until 2019 to launch 5G services, when the first mobile devices are expected to be available.

Ray said he would rather “commit our effort to something way more meaningful for the consumer” than launch a service using routers: a thinly-veiled attack on AT&T’s plan to launch mobile 5G services in late 2018 using a device it calls a puck.

Sprint’s Saw was bolder, directly referencing AT&T’s approach and its CEO Randall Stephenson: “The first application we’re driving for is mobile 5G,” he said, adding the operator is “determined to launch the first device as a phone, not a puck, as Randall calls it.”

Deployment plans
Ray made the comments as he revealed T-Mobile plans to build a 5G network in 30 US cities this year spanning its 600MHz, 28GHz and 39GHz airwaves using equipment from Ericsson and Nokia.

The operator’s rollout will start in “places that matter”, including New York City, Los Angeles, Las Vegas and Dallas. Work deploying “5G-ready” radios on 600MHz has already begun, and Ray said standards-based mmWave radios will become available in the fourth quarter.

The CTO noted T-Mobile has 200MHz of mmWave spectrum to play with in urban areas across the country. He said the operator expects mmWave radios to have a range of up to 200 metres, but added there’s still “a lot to learn” about how mmWave works.

“I think as an industry we have to be honest with ourselves, we have to understand how well is that millimetre wave going to work. How well is it going to propagate in some of these dense urban environments, how well is multi-path and massive MIMO going to work? [There’s] a lot of complexity both in the radio and handset to figure out.”

Massive MIMO to 5G
In a separate briefing, Saw elaborated on the operator’s plans to lay the groundwork for 5G with Massive MIMO deployments in six cities this year.

The CTO said the technology will be installed across Sprint’s 2.5GHz footprint, starting with thousands of sites this year and building toward tens of thousands of sites in 2019. He added Sprint’s use of its 2.5GHz footprint will allow for a more consistent geographic 5G experience, unlike the urban mmWave hotspots competitors are deploying.

Saw noted the Massive MIMO radios will be software upgradable to 5G through the installation of a new channel card at the base of the tower and feature a split mode capability that allows for simultaneous deployment of 60MHz of 2.5GHz spectrum for LTE and an additional 60MHz for 5G. Saw said the phones Sprint will be releasing in 2019 will include dual connectivity, enabling access to the full 120MHz of spectrum.

“That’s how I’m going to drive more than 2Gb/s of speed natively. When I say natively I mean not using tricks like unlicensed or LAA where there are concerns about whether you can get LAA all the time.”

T-Mobile’s Ray said any 5G layer built on top of an operator’s LTE network will boost handset performance but was careful to note multi-gigabit speeds won’t be an immediate reality.

“We would love to see average speeds triple or move to 100Mb/s but that’s a journey that’s going to take time in the industry.” He continued: “We have to be careful about saying we’re going to have multi-gigabit experiences across all swaths of geography in the US or anywhere in the world. It’s going to take a long, long time and a lot of spectrum for us to get to those types of capabilities.”