After more than a year of 5G, this chilly week in the US has brought a cold blast of reality to the early deployments of the next-generation of high-band wireless by AT&T Inc. (NYSE: T) and Verizon Communications Inc. (NYSE: VZ)

Verizon is slowing its roll on any more of its residential 5G launches until mobile 5G arrives with 3GPP-compatible 28GHz smartphones, set to appear later this year. Verizon CEO Hans Vestberg expects the devices to arrive in the first half of 2019. (See Verizon CEO Expects Standard 5G Phones First, '5G Home' CPE to Follow in 2019 and A 5G Device Timeline for 2019.)

Verizon is using the 28GHz millimeter wave band for both the fixed 5G Home service it offers in parts of US four cities -- in limited areas of Houston, Indianapolis, Los Angeles and Sacramento. The operator intends to use the same frequency for its standard mobile service. (See 5G in the USA: A Post-CES Update.)

"What we're waiting for right now is the [3GPP-compatible] CPE equipment for 5G Home," Vestberg said on Verizon's fourth-quarter earnings call. "We definitely believe that this year we will get CPEs on the NR standard in the second half of 2019." (See Analyst: Verizon's Fixed 5G Is a Loss Leader for Mobile.)

This won't mean that Verizon can stop deploying 5G in the US; it just won't use its home-grown 5G Technology Forum (5GTF) specification anymore. Instead, the network it deploys will be a 3GPP 5G New Radio (5G NR) "multi-use" fixed and mobile network.

"We're building the network as we're speaking," Vestberg noted.

So, the big question coming now for potential Verizon mobile 5G customers is: What kind of coverage will its standard mobile network offer? There's no solid data on this yet from Verizon, but remember that that the fixed option offered coverage in the range of around 2,000 feet. In a city environment, such as New York, that could mean installing 5G small cells every city block to provide good coverage! (See Millimeter Wave 5G: The Usain Bolt of Wireless? and 5G Demos Show the Tech's Spectrum Achilles Heel.)

Meanwhile, on the 5G device side, millimeter waves antennas use such tiny signals that they can be blocked by the human hand. Fun, right? (See 5G Phone Designers Coping With 'Human Blockage'.)

Rival AT&T Inc. (NYSE: T), meanwhile, appears to have concluded this week that its millimeter wave standard 3GPP mobile 5G efforts will be similarly limited in the US. The operator has parts of 12 markets up and running now and plans seven more this year. After that, AT&T promises, with low-band, to bring 3GPP 5G nationwide through the last half of 2019 and into 2020.(See AT&T's 5G Switches On in 12 US Cities, but Only for 'Early Adopters' and AT&T Low-Band 5G to Arrive With Samsung Phone in 2H19.)

In fact, AT&T CEO Randall Stephenson said this week that he sees millimeter wave 5G becoming a wired broadband alternative "over a three-to-five-year timeframe," serving as "a true replacement opportunity" to take on cable broadband. That gives the impression that AT&T is becoming realistic about the capabilities of millimeter wave technology. (See AT&T CEO: mmWave 5G Will Be Fixed Broadband Alternative in '3 to 5 Years'.)

The timeframe suggests far more network buildout is required to support services that can offer cable-like broadband performance (or better) from millimeter waves. Of course, the CEO didn't provide much additional information about that beyond his comments on the earnings call.

Nonetheless, the AT&T and Verizon statements start the year off with a more realistic approach to millimeter wave 5G in 2019 (and beyond). Let's see what happens next...

— Dan Jones, Mobile Editor, Light Reading