T-Mobile quietly testing Cel-Fi femtocell alternative for customers in signal-challenged areas

T-Mobile could be the first U.S. carrier to offer 3G signal boosting devices that don't require broadband.

Most mobile phone subscribers probably have decent overall coverage for both voice and data, particularly in cities and suburbs. But, whether it's AT&T's network being strained by iPhone users (a problem that the rapid influx of smartphones is likely to pose for all carriers, as I talked about yesterday), living in a rural part of the country, or for other reasons, a lot of users still have trouble getting a strong signal at home or in the office (in may case, it's caused by living in a very solidly built 150 year-old brick brownstone as well as AT&T's network).

There are plenty of conventional ways to mitigate the problem – use a landline phone and wired Internet connection, stand closer to a window, or wander around looking like an extra from Star Trek trying to find the spot with the best signal.

More recently, mobile carriers have begun to step in to help subscribers combat the problem more effectively. In some cases, like AT&T's Mark the Spot app for the iPhone, this is in the form of letting users simply report areas where they experience problems (and yes, AT&T does respond to reports some of the time and does inform users that made the reports if they do).

In other cases, carriers have begun relying on devices to help users out. The most well-known of these devices are femtocells, essentially Voice over IP (VOIP) routers that use a subscriber's broadband connection to offload both voice and data service. AT&T began offer the Microcell this year for users suffering from connectivity issues related to network congestion as well as users in more remote areas where coverage is weak, spotty, or non-existent. Other carriers also offer femtocell products as well – unfortunately femtocell devices, which typically support up to four devices each) are often purchases subscribers must make out of their own pocket (often in the $150 to $250 price range) and even with off-loading, they're use for calls still subtracts from a user's minutes because the carrier network must still be involved in the call.

Recently, T-Mobile has quietly begun testing and alternative to femtocells. The Cel-Fi device is actually a signal booster. Unlike a femtocell, it doesn't rely on a broadband connection (good for locations where broadband access or speeds may be limited). Instead, it allows a user to place a receiver in the location in a building where there is the strongest signal (yes, more walking around like a Star Trek character) and a broadcasting device where the signal is weakest of non-existent. The result is that, other than electricity, the user doesn't need to provide anything of their own (as this is still in early testing, it's unclear if the device will be provided free or not).

If the trials are successful, this could be a much better approach than the traditional femtocell. However, even if the Cel-Fi trials pan out, it won't be a perfect solution for everyone. While the Cel-Fi can boost a signal (providing better voice quality and data throughput as well as battery life because a phone's radio doesn't need to work as hard), it does require a signal, even a fairly weak one.

While it isn't a panacea, the Cel-Fi trials show T-Mobile (and possibly other carriers) are still working to develop ways to provide better service to customers and that femtocell's may not be the only option. In fact, if the Cel-Fi is successful, it may have broader appeal because of the lower cost and because the approach might scale better, allowing for models that can accommodate whole office with a number of devices instead of just a handful in a home.

Ryan Faas writes about personal technology for ITworld. Learn more about Faas' published works and training and consulting services at www.ryanfass.com. Follow him on Twitter @ryanfaas.

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