Verizon relies on dynamic spectrum sharing more widely than AT&T – report

All eyes may be on U.S. carriers’ current and upcoming upper mid-band spectrum deployments, but for the time being 5G is largely still being delivered with spectrum in lower bands and using a technology that shares spectrum with 4G LTE.

Verizon continues to use dynamic spectrum sharing (DSS) technology for 5G more widely than its rivals, according to network testing by Global Wireless Solutions.

In a report released Wednesday, GWS said it observed DSS deployed by Verizon in 229 of the 498 markets tested. Of those, DSS was used in 23% of 5G tasks initiated by GWS on the carrier’s network.

AT&T also taps DSS for 5G, though the GWS report observed deployments in just 22 of the nearly 500 markets. And of that, DSS was used in 5% of GWS-initiated 5G tasks on the carrier’s network.

T-Mobile (which early on had been a more vocal critic of DSS shortcomings) had it deployed in three markets tested and utilized DSS in just 2% of 5G tasks. T-Mobile has dedicated low-band 600 MHz, as well as mid-band 2.5 GHz deployed for 5G.

Tasks included a network capacity stress test, both large and small file uploads and downloads, and video tests, according to GWS CEO Paul Carter.

Verizon first rolled out dynamic spectrum sharing roughly one year ago when it debuted broad 5G coverage, versus earlier limited deployments strictly using high-band millimeter wave spectrum dedicated to 5G. The technology enables sharing of a spectrum channel, dynamically allocating resources to either New Radio (NR) or LTE technology based on usage.

Verizon says it has DSS deployed in 2,700 cities for 5G Nationwide coverage. That lines up with GWS tests, Carter explained, as the company presents data in terms of “markets” which typically include multiple cities. The U.S. has around 20,000 cities in total – and about 15,000 of those have populations under 5,000, he noted.

GWS’ method uses drive tests, testing 92% of the population across just under 500 markets.

“When we compared Verizon’s online 5G coverage map to the markets where we saw DSS, the two matched very closely,” Carter told Fierce.

Overall, in the combined markets where GWS detected Verizon 5G coverage, a signal was actively available 22% of the time. For an AT&T 5G signal, it was 45% and for T-Mobile 35%.

“GWS observed Verizon’s 5G coverage (which is mostly DSS) starting in the urban areas and covering most of the suburban areas,” Carter said via email. “There appeared to be little reach in the rural markets at this point.”

DSS has been hailed as a way to quickly deliver 5G coverage without having to refarm and dedicate spectrum to a particular technology. As spectrum is a scarce resource, it means operators don’t have to take away from 4G LTE users for what, at the early stage, are fairly uncongested and unburdened 5G networks. However, DSS received some criticism, including by competitor T-Mobile last year. And previous tests by Signals Research Group categorized performance of Verizon’s DSS as disappointing.

Still, without chunks of available spectrum to set aside strictly for 5G (that is before Verizon acquired 180-megahertz of mid-band 3.7 GHz C-band spectrum, including 60-megahertz that will start rolling out in December across 46 markets), DSS is a way to share bandwidth and claim nationwide 5G.

And when it comes to low and mid-band spectrum (below 2.5 GHz) – Verizon has less than its peers. A recent post by LightShed Partners showed Verizon holding about 117 megahertz of low and mid-band (not including C-band), compared to 185 megahertz for AT&T and 152 megahertz for T-Mobile.

AT&T set aside dedicated spectrum in the 850 MHz band for 5G in most of its markets, but sometimes utilizes a channel in the 1900 MHz or 2100 MHz bands, Carter said. In markets where GWS found DSS deployed, AT&T usually used the 850 MHz band, except for a couple of markets using 2100 MHz.

Similarly, Verizon is mostly tapping 850 MHz spectrum for DSS using 10-megahertz bandwidth channels, according to Carter. He said there’s also some 1900 MHz band DSS in Southeastern markets using 10-15 megahertz channels.

For the recent GWS results, Carter said they measured “very little performance difference” between Verizon 5G using DSS and similar standalone 4G LTE channel.

“5G is supposed to be a little more efficient, however, DSS requires a small amount of overhead that is not needed for a standalone 5G or 4G channel. As such, the performance ends up being similar.”

The updated conclusion is in line with previous network results – multiple third-party tests have shown early 5G performance for carriers isn’t blowing 4G out of the water.

And combined results of 4G and 5G data points GWS still found Verizon had the fastest download speeds for small tasks like web browsing and app data. It was second behind AT&T when it came to large downloads like receiving video and photos. Verizon had the fastest uploads on both big and small tasks when 4G and 5G were combined.

Verizon placed second (behind T-Mobile) for highest average throughput in network capacity stress tests. Same goes for strictly 5G where T-Mobile’s speediest average throughput in the stress test was 95 Mbps, Verizon was 80 Mbps and AT&T was 58 Mbps. Overall, across data points as well as consumer survey results GWS ranked AT&T first for best network, Verizon second, and T-Mobile third.