T-Mobile Launches Vo-Fi Nationwide

The new Hotspot @Home service allows handoff from cell network to any open Wi-Fi connection without losing the call.

By Eric Griffith | Posted Jun 28, 2007
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Although it may have been overshadowed by this week's iPhone hullabaloo, T-Mobile USA had a very significant announcement—one that fulfills a promise made years ago: Subscribers to the carrier's new Hotspot @Home service—unveiled yesterday—will be able to make inexpensive IP-based calls when in the presence of a Wi-Fi access point, rather than having all mobile calls travel across the cellular access network.

After several months of trials in the Seattle area, the company has taken Hotspot @Home live nationwide. The service, which requires a (relatively inexpensive) dual-mode phone supporting both T-Mobile's GSM/GPRS/EDGE network and Wi-Fi, lets users make unlimited calls for an additional $10 a month over the cellular T-Mobile subscription rate, or $20 a month for up to five lines on a family plan.

The Hotspot @Home network is powered by Unlicensed Mobile Access (UMA) technology, which enables seamless hand-off between Wi-Fi and cellular. The "unlimited" calling policy applies only the VoIP calls made over Wi-Fi, of course—with the exception of calls initiated on the Wi-Fi side that then roam to the cell network, which remain un-metered.

Investor research firm ThinkEquity calls this fixed/mobile convergence (F/MC) launch by T-Mobile "the most important architectural shift in cell phone technology since the introduction of digital GSM in 1992."

To launch the service, phones are needed, and two vendors announced new handsets to support it this week: the Nokia 6086 and the Samsung SGH-t409. Both will retail through T-Mobile for $50 with a two-year contract. In addition to Wi-Fi and GSM, each supports Bluetooth (for headsets only) and has a built-in camera (but you can't connect to a computer to send the pictures — you need a USB cable, which is not included). The Nokia phone records video and takes microSD cards for expansion.

Users are not limited to Wi-Fi calls on their home networks. The phones will work with any open Wi-Fi connection, as well as the T-Mobile HotSpot network of 8,500 locations in the U.S. Calls made at these locations won't cost anything. T-Mobile will also be selling home wireless routers from Linksys and D-Link that it says are optimized for the service by supporting the WMM standard, part of 802.11e with a proprietary method for setting up a secure link. The routers will be free after a mail-in rebate. T-Mobile apparently won't guarantee call quality with other routers, nor at non-T-Mobile hotspots. T-Mobile hotspots all have full T-1 lines for backhaul to the Internet, while typical public hotspots with open access are likely only to have DSL or cable connections in the background.

The iPhone, while carrying Wi-Fi, will not support this kind of hand-off, as its exclusive carrier, AT&T, doesn't use it. Wi-Fi on the iPhone will likely be used for data only, unless Apple introduces a VoIP application in the future—which is unlikely, since AT&T won't want iPhone users to avoid using its voice network. Glenn Fleishman of Wi-Fi Networking News notes that "T-Mobile is focused entirely on voice here; Apple, on a broad 'digital life' experience that includes voice, Internet access, and media, with no network integration among the three."

The Hotspot @Home service and the Nokia and Samsung handsets can be purchased at T-Mobile retail stories or online.

Adapted from Wi-Fi Planet.

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