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T-Mobile's HotSpot @Home: Wi-Fi VoIP Plus GSM Roam

-August 01, 2007

Truth be told, frankly, I come across very few fundamental technical breakthroughs and very few fundamentally brilliant business strategies in my job. Most of the product pitches I hear are all too predictable; lithography shrinks lead to chips that run faster and cooler than their predecessors (at least this used to be predictably true, before the era of excessive leakage current!), that are more cost-effective than their forerunners on a transistors-per-square inch unit basis, and that squeeze more transistors onto a cost-effective sliver of silicon than did their precursors. And the system evolutions based on those chip evolutions are equally foreseeable. Arguably, much of the technology being implemented today, in both hardware and software forms, comes out of academic and industry research years-to-decades old; Moore’s Law integration trends have just now made its implementation practical.

My longstanding search for rare, truly innovative ideas explains why I was so jazzed when I first heard about T-Mobile’s unique HotSpot @Home service back in early August of last year. I’ve been closely following various wireless VoIP experiments, along with the accompanying infrastructure build-outs (WiMAX, municipal Wi-Fi, etc.) ever since I postulated, in an admittedly controversial post crafted while at the May 2005 NAB Conference, that we were at the foundation stage of an IP-based communications technology that might someday pose a serious competitive threat to cellular providers. This is the first in what will hopefully in the near future be a series of related writeups from me; on wireless Skype handsets, on Skype and other VoIP software running on Wi-Fi-inclusive portable devices, on my experiences with Google’s Wi-Fi network in Mountain View, CA, etc.

HotSpot @Home works in conjunction with otherwise-conventional cellular phones that also embed Wi-Fi capabilities. It employs the UMA (for Unlicensed Mobile Access, also known as GAN, for Generic Access Network) protocol to route voice calls over the Internet, coordinated by T-Mobile servers. For an incremental $10 beyond your normal cellular bill, you’re able to make unlimited-duration U.S. nationwide calls whenever you’re Wi-Fi-connected. And, if you initiate a call over Wi-Fi but, during the call, move beyond 802.11 coverage range, the phone automatically switches to GSM mode and your call continues unabated, without using cellular minutes.

So why was I so impressed with HotSpot @Home? From a big-picture perspective, T-Mobile is the only major U.S. cellular provider without a lucrative in-house landline business that it needs to protect. Therefore, not only does HotSpot @Home potentially keep T-Mobile from losing business to mobile VoIP competitors, it also potentially also enables the company to steal POTS (and-therefore also cellular, by virtue of the HotSpot @Home program’s bundled nature) business from cellular competitors AT&T, Sprint and Verizon. And it also conveniently leverages T-Mobile’s nationwide HotSpot 802.11 network, found in places such as Borders Books, FedEx Kinkos, Starbucks, and a variety of airports and hotels.

From reading my past writeups, you may also already remember that I’m a T-Mobile cellular and HotSpot subscriber, and that I have lousy GSM coverage within my home….both factors thereby explaining why I was intrigued by Hotspot @Home from a personal standpoint. Unfortunately, T-Mobile’s PR contacts claim there’s no plan (at least yet….although this long-time Windows Mobile user remains hopeful) to add UMA capabilities to the T-Mobile SDA I own as a backup to its near-clone and my primary phone, an iMate SP5m. But last week the company sent me a Samsung SGH-t409 handset (the Nokia 6068 also supports HotSpot @Home) and a Linksys WRT54G-TM router (ditto for D-Link’s TM-G5240 router) to test-drive.

As I reminded you a paragraph ago, my GSM coverage at the Sacramento, CA home office is sketchy. I was concerned that Wi-Fi-to-GSM handoffs would unfairly suffer and was therefore resistant to doing a full-blown HotSpot @Home test there. This week, however, I’m up at our mountain dome abode, which has excellent T-Mobile coverage, especially when enhanced by Spotwave’s cellular booster. T-Mobile’s literature claims that you can use a HotSpot @Home-capable phone with any Wi-Fi network, so instead of firing up the Linksys WRT54G-TM, I instead paired the Samsung SGH-t409 with my existing Linksys WRT54GC.

Continue reading with ‘T-Mobile’s HotSpot @Home: Hot Or Not, From My Geodesic Dome?‘….

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