T-Mobile’s WiFi-Cellular Summer


http://online.wsj.com/public/article/SB117815938377190497-DngF5xT5ggq9fyTC_rJOQvttONk_20080502.htmlT-Mobile’s Wi-Fi cellular converged phone service is supposedly breaking out of its Seattle trial and going nationwide this summer, according to the Wall Street Journal. The article says that some time in mid-June T-Mobile is going to do a national launch of its ‘Hotspot at Home’ service along with the dual mode phones that are based on a standard called Unlicensed Mobile Access, popularly known by its acronym, UMA.

When we wrote about T-Mobile’s Seattle trial last August, it wasn’t clear then if T-Mobile had already provisioned the service to be used outside of the home, at public hotpots in Seattle. Though, this morning’s article says the national service can be used at coffee shops.

It’s a natural move and the public hotpots are T-Mobile’s trump card. More than any other carrier, T-Mobile’s Wi-Fi real estate gives the fourth largest carrier the incentive to use UMA and Wi-Fi cellular convergence.

The service is by no means a sure bet of commercial success. T-Mobile parent Deutsche Telekom actually cancelled its fixed/mobile convergence service called T-One in Germany. That service was based on a protocol called SIP over Wi-Fi and cellular. Light Reading says the service was thought to be too expensive, poorly marketed, and lacked compelling features.”

UMA is also a controversial topic in some telecom circles. ‘UMA is dead,’ is a common sentiment from startups and our readers have fiercely debated the technology’s technical merits. The WSJ article says:

T-Mobile has had some technological problems with the project, such as making a smooth handoff between the cellphone and Wi-Fi networks and maintaining battery life, people familiar with the trials say. Many of those issues have been ironed out in the latest versions of the Wi-Fi phones, those people say.

UMA is basically an international standard that has been in development for years by a consortium of carriers and companies. The technology works with both Wi-Fi and bluetooth and uses dual-mode phones to roam between Wi-Fi and cellular networks.

Deployment of wide-reaching UMA services require UMA infrastructure in the network that companies like Alcatel, Nokia, Kineto Wireless, Motorola and Ericsson provide, as well as UMA software on dual-mode handsets developed by Motorola, Nokia, and Kineto.

As voice becomes even more of a commodity service and use of data services grows, the carriers all know that they need to adopt converged network services and offer easier ways to roam across networks. Most carriers are terrified of losing some of the revenues from cellular voice calls to cheaper Wi-Fi voice calls.

But as Wi-Fi and other wireless networks grow, there is really no way around it, and UMA offers some level of control. Because T-Mobile has been working on Wi-Fi hotspots for years, it has a head start in this market in the U.S.



“What they lack is a WiFi network where all of these elements could be put into play”

I agree, they should provide a service for hotspot operators, just like they provide Google Analytics etc. That way they can let operators build hotspots/wifi networks on their software infrastructure..I’d say it sounds much better than actually setting up hotspots which is what T-Mobile has done at starbucks.

Katie says ‘Public hotspots are t-mobs trump card’. So for GooG to have a hotspot network may not be a bad idea??


Google might be in this game too…They have the Google Phone said to be coming out, Muni WiFi plans, Google talk etc…What they lack is a WiFi network where all of these elements could be put into play.


I dont see anything mentioned about the ability to use 4G WIFI strapless side loading MM for free.


I’ve seen more reference to the fact that the T-One service in Germany used UMA rather than VCC (SIP-based), but perhaps it was both. Does anyone have more complete information?


Mike Puchol

This could mean an open door to liberate Starbucks and others from the contracts that restrict their offer to T-Mobile’s for-pay WiFi. I don’t have usage data, but I bet T-Mobile could make a lot more money from the voice traffic at Starbucks WiFi, while also giving a portion of said WiFi bandwidth for free to customers and their laptops. You’d get free surfing plus cheap calls, and nice but expensive coffee – bliss!

Jesse Kopelman

Jeb asked, “Can’t T-Mobile just pick the 2100 band to use for 3G?”

The 2100 band in the US does not line up very well with the the 2100 band in Europe. A major reason for that is because in the US the spectrum is actually paired channels split between 1700 and 2100 MHz. So, this means yet another new RF module inside the phones to support it. Just as today’s GSM phones usually support 850/900/1800/1900, I’d imagine future phones will support 850/900/1700/1800/1900/2100. US 1700/2100 licenses (AWS) have just recently been won, so I wouldn’t expect to see vendors including this support in their devices before 2H08. By the way, Cingular has AWS spectrum as well, so this would not be a differentiator for T-Mobile.

Jesse Kopelman

The way UMA works is a tunneling concept similar to VPN and as such will work with any WiFi network your device can connect to. That said, your usage can be metered an T-Mobile may very well charge you air time for connecting through an “unofficial network”. This is a key concept that people miss about UMA — it is just as much about enabling carriers to charge you for WiFi connections as it is about cellular/WiFi roaming. UMA requires a specific device support, it will not work on just any phone that has both WiFi and GSM radios.

Libran Lover

I think the service will be restricted to their own WiFi networks or a network which is registered with them in some way. I simply can’t imagine a telco today being so open as to allow usage on any Wi-Fi network – ‘today’ being the operative word.

What I want to know is, if they will allow using two different phones? For example, can I take my cell phone with me when I am outside the house to use on a cellular network, while leaving a dual phone at home for my family to use over Wi-Fi?



I agree, as long as you have access to a network it probably will work. So if your mobile device is an authorized entity of a wireless network (such as the corporate scenario you pointed out -OR- any free wifi network) it might be able to do the handoff.

But most relevant commercial hotspot locations such as airports, hotels etc do not fall under this category. For example Boingo probably has the most widespread access to airports (if I’m not wrong it came with the concourse acquisition), so the question is – will T-Mobile have a roaming agreement with those guys (who operate large commercial wifi networks) to allow their subscribers to access all or most of the relevant public networks? i.e. locations where the case for UMA do make some sense.


I do not think it will be restricted. You do not need t-mobiles router to use it at home. So I cant see them really restricting it. Plus this could be huge for corporate cusotmers who get bad cell reception and or want a cheap unlimited plan plus cell access for their employees.


My assumption is that it will be restricted to Starbucks.

On one hand the service might become very popular because of the ability to roam aross any commercial network (if they allow that) and that might bring in a lot more subscribers, albeit less ARPU. So I guess they will have to find that point in the graph where things makes sense from a moolah perspective.

But then since UMA isn’t really proven in the market place yet (at least in a big scale), it might just be a fad afterall.

Katie Fehrenbacher

Sanjay, Sam, I agree that open Wi-Fi roaming would be nice. T-Mobile hasnt gotten back to me yet on how restrictive its access to Wi-Fi networks will be. From talking to other sources I think they will likely try to limit users to the home and their own hotspots for the time being. I imagine they are pretty nervous about cities like Mountain View with muniFi.


Must we use the 2 phones T-Mobile was testing with or can we use our own duel band phones, like my Nokia E61?
Side Note: Can’t T-Mobile just pick the 2100 band to use for 3G? Then our phones with 3G from Europe would work on T-Mobile. Cingular uses a different band so people like myself would most likely switch to T-Mobile.

sam gonzales

I concur..it would be super nice if you can hop on any hotspot you have acess too such as the office, girlfriends home, etc.. with this and myfave and their 3G plans..tmobile will gain some nice market share


Wondering whether the ability to move between wifi-cellular is restricted to only Starbucks locations? (apart from the subscribers home). Would be nice if they allow it to happen over any commerical network

T-Mobile tester

I’ve been testing the service in Boston for the past 2 weeks. Works pretty well.

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