LAS VEGAS—Listen to this. T-Mobile just beat every other U.S. carrier bringing HD Voice to market, delivering a radical improvement in call quality for everyone carrying an HTC One S, Samsung Galaxy S III, or Nokia Astound phone. And wait, it gets better—it might work with iPhones.
"It's a very noticeable enhancement to the voice call," said Neville Ray, T-Mobile's CTO.
He's right. T-Mobile gave me a quick demo of the new system, and it's definitely an improvement. The demo compared two calls from a noisy coffee-shop-like location. In the HD Voice call, the background noise receded, although it didn't vanish. Very noticeably, though, the caller's voice really jumped forward, and the caller's tone became much richer and more well-rounded.
"I would challenge the assertion that one is better than the other," Ray said in response.
The three phones T-Mobile is launching with don't need any upgrades to use HD Voice, and more HD Voice-compatible phones will come soon, Ray said.
So Many HD Voices
T-Mobile's HD Voice is the most established version of the several technologies which use that name. HD Voice calls on T-Mobile run over the carrier's existing 3G network, but switch voice encoders to AMR-WB (adaptive multi-rate, wideband), which has better sound quality than the existing AMR codec.
There are at least two other ways to make that call, though. Sprint is using a different codec, EVRC-NW, over its CDMA 1X Advanced network. AT&T and Verizon both intend to implement HD Voice over voice-over-LTE (VoLTE) networks. For now, all of those approaches are incompatible.
So you'll only get HD Voice quality when both people on a call are using T-Mobile HD Voice phones. And while carriers are working on interoperability, we may never have HD Voice calls to landlines, Ray said.
What About the iPhone?
T-Mobile might be the first carrier to bring an HD Voice iPhone to the US—but we don't quite know.
The current iPhone 5 supports AMR-WB, the HD Voice codec T-Mobile uses. While T-Mobile doesn't sell the iPhone yet (it's coming "in 2013," according to Ray), it's hosting a lot of iPhones pulled over from AT&T: 1.9 million right now, with 100,000 more coming per month, he said.
iPhone users have increased their pace of movement over to T-Mobile as T-Mobile has improved its iPhone-compatible 4G network, Ray said. Today the carrier announced Denver, Los Angeles, San Diego, and Virginia Beach now have iPhone-compatible HSPA networks, with 126 million people now able to use AT&T's 1900Mhz HSPA phones at full speed on T-Mobile's network.
"I don't know if iPhone 5s will work. It depends on how Apple has configured the setup," Ray said. That's certainly something for iPhone 5 users on T-Mobile to check out. AT&T doesn't support, and has said it will never support, AMR-WB on the iPhone.
T-Mobile HD Voice is live now.