T-Mobile Launches Dual-Mode Service in Seattle

The big wireless news so far this week is T-Mobile’s launch of its dual-mode WiFi/Cellular service in Seattle.

TMCnet Associate Editor Patrick Barnard reported yesterday that the new service “lets T-Mobile’s subscribers make free phone calls using their at-home WiFi network or from any number of public WiFi hot spots which have been set up throughout the city. For now, only subscribers using the Nokia 6136 and the Samsung T709 dual mode phones can place free calls over WiFi.”

The new service uses Unlicensed Mobile Access (UMA) technology, which was developed by Kineto Wireless and is now part of 3rd Generation Partnership Project’s (3GPP) standards. (T-Mobile also is using femtocell technology to enhance wireless network coverage, according to TMCnet Executive Editor Robert Liu.)

Liu, who reported last month on T-Mobile’s service ahead of its official deployment in Seattle, corresponded today by e-mail with Kineto Director of Marketing Steve Shaw, to get some additional details about how the service functions.

In an e-mail correspondence, Shaw told Liu that UMA enables true seamless handover between WiFi and cellular networks, “without any noticeable (sub 50 msec) service interruption.”

UMA enables this functionality, Shaw explained, because it works in the same way as a base station  controller in a cellular network.

“When you drive across town, your GSM call is seamlessly handed between BSCs and radio antennas as you drive,” Shaw said. “UMA uses the exact same technology to accomplish call handovers.”

For subscribers, the benefits are pretty obvious: the ability to conserve cell phone minutes and make calls from any location. Using the service in a WiFi hotspot (T-Mobile says it plans to increase the number of hotspots it already maintains) gives subscribers access to transfer speeds faster than even 3G cellular—making it possible to download content such as music, videos, and games.

T-Mobile wins first prize when it comes to rolling out national, U.S. dual-mode service—but lags somewhat behind in the global race. British Telecom was first to market globally, with the roll-out of its Fusion a year ago June. TeliaSonera’s dual-mode service, Home Free, followed suit earlier this fall, and Orange’s unik was fast on its heels. Telecom Italia also launched a dual-mode service last month.

In his article, Barnard raises some questions about how T-Mobile will handle billing of the service—specifically, whether or not it will be difficult for subscribers to keep track of how many cellular minutes they’ve used. I won’t be a spoiler, though—check out the article yourself to see some of the questions T-Mobile hasn’t yet answered about its new service.

The biggest question I still have is: are consumers actually interested in dual-mode services? I suspect the answer will lie in how easy the new services are to use, and to what extent they help people save money on their phone bills.