Can you hear me now? Mobile operators beef up networks for conventions - CNET

"Wireless customers definitely remember if service doesn't work well," said Mark Walker, who runs Sprint's network in the northeast. "It's just expected that your phone will work wherever you are and whenever you want."

Of course, the carriers have plenty of experience preparing for major events. The Super Bowl, the NFL's Christmas in February, attracted more than a million people to the Bay Area for its weeklong pigskin bacchanal. Even regular season games in Cleveland and Philly attract between 65,000 to 70,000 fans, more than the 50,000 attendees each convention is likely to get.

The carriers wouldn't provide estimates of how much they've spent on improvements to their wireless networks for the conventions, but they say the work has been extensive. AT&T executives told CNET sister publication TechRepublic that the company has invested $250 million in wireless and wireline network upgrades in Cleveland alone.

In the same city, Sprint has added support for lower band 800 MHz wireless spectrum, which improves indoor network coverage and call quality. (The carrier has done the same in Philadelphia.)

Verizon has doubled network capacity to links into the Quicken Loans Arena. It's also beefed up small cell coverage in the area around the arena. Small cells let wireless operators shrink the area of cellular coverage so that it can reuse the wireless airwaves to pack in more users. Verizon also added on-the-floor antennas to provide coverage for delegates.

In Philadelphia, the carriers are trying to build on improvements made for the city's last big event, the 2015 visit of Pope Francis. During that two-day event, AT&T's customers used 12.6 terabytes of data, which is equal to 36 million social-media posts with photos, the company said. AT&T also reported that traffic was 12 times greater that weekend than the average weekend usage along the Benjamin Franklin Parkway, where millions watched the pope's motorcade and listened to the papal Mass.

AT&T is doubling capacity for the Wells Fargo Center, where most of the convention action will take place, while T-Mobile is upgrading the cellular antennas inside the arena, as well as at the Pennsylvania Convention Center. The improvements include upgrading the components of its distributed antenna system and adding fiber connections to high-traffic areas.

New Sprint technology accommodates the use of its 2.5 Gbps wireless spectrum, which allows for faster 4G service. Verizon says it has increased capacity at the Wells Fargo Center by an estimated 550 percent.