Femtocell FAQ: Time for a 'personal mobile phone tower'?

Are you one of those unlucky souls who enjoys decent mobile phone reception when you're out and about, but can't get a signal at home or in the office? You're not alone. Indoor phone calls have long been a weak point of cellular coverage.

That's why femtocell technology has created such a stir over the past year or so, as the idea of using a device like a broadband router to boost cellular reception indoors has seemed to be on the verge of materializing. Analysts and the media speculated that consumers would see a flood of such devices, known as femtocells, by the end of 2008.

Now, however, that timeline has shifted to late 2009 or 2010 as a number of questions surrounding femtocells remain unanswered. In fact, only Sprint Nextel is currently offering a commercial femtocell product in the US.

This gap between the initial hype and the eventual introduction of femtocells has one advantage, however: It gives consumers a chance to learn more about the technology, including its benefits and drawbacks.

What are femtocells?

The term "femtocell" refers to the smallest unit of a cellular network and, by extension, the devices and services that make use of them. Other small -- but not quite as small -- cells include Wi-Fi cells (a.k.a. microcells) and Bluetooth cells (picocells). At the other end of the spectrum are macrocells, such as those used in carriers' mobile phone towers.

What do they do?

Femtocells address the problem of poor mobile phone reception indoors by taking advantage of the proliferation of home and small office broadband connections. Like the wireless router that distributes a DSL or cable broadband signal throughout your home, a femtocell device -- sometimes called a miniature cellular base station or a mini-cell tower -- grabs your carrier's cellular signal and boosts it for indoor use, routing your calls through the broadband connection rather than directly through the larger cellular network.

What are the benefits?

Subscribers get a stronger, clearer, more reliable signal at home -- which means more users may finally be able to ditch their landline phone service for good. Carriers benefit by being able to offload traffic from their main networks, saving the substantial cost of building more towers.

How far do they reach?

Femtocells have a range of around 5,000 square feet.

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Femtocells are not like broadband routers, where you can choose from among a number of hardware vendors. Because femtocell devices are tied to wireless carriers using licensed spectrum, you have to wait for your mobile provider to offer femtocell service.

In September 2007, Sprint Nextel became the first US carrier to introduce a femtocell service, called Airave, in the cities of Denver and Indianapolis. The company rolled out the service nationwide in August 2008. A femtocell box plugs into your existing router or modem, sending incoming and outgoing cellular calls through your broadband connection. Up to three callers can use the service at the same time.

Outside the US, femtocell trials are under way in the UK (through the provider O2), Spain (Vodafone) and Japan (Softbank); Softbank plans to roll out a 3G femtocell data service in Japan in January 2009. Analysts such as Stuart Carlaw at ABI Research predict that a million femtocell devices could be sold worldwide this year, with 150 million users by 2012.

How much does it cost?

Cost is one of the questions still without a clear answer. Critics point to the many fees associated with Sprint's Airave femtocell service. First, there's the US$100 cost of the box. Then there's the US$5 monthly service charge, in addition to the fee for your regular calling plan and minutes used. If you don't already have an unlimited plan, you can opt to pay an extra US$10 a month for unlimited Airave minutes; for families, that's an extra US$20 per month. Finally, add the cost of your broadband service.

"If the 'network is everywhere,' it might be a hard sell to tell their customers, 'It's everywhere but in your house, and for that, we want another $100,'" said Allen Nogee, an analyst at In-Stat.

"You really can't sell these as stand-alone boxes," ABI's Carlaw says. Carriers will need to market the service as part of a flat-rate data plan, he says.

What if I switch carriers?

Because femtocells are locked to individual carriers, if you switch wireless providers, you'll need to purchase a new box.

Can I use my existing phone?

Yes. One selling point for femtocells is that they will work with your current mobile phone. Similar services that use Wi-Fi for offloading home calls, such as T-Mobile's HotSpot@Home, require consumers to purchase a dual-mode handset.

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Sprint's Airave, the only femtocell service commercially available in the US today, supports 1xRTT data but does not support high-speed 1xEV-DO data. However, 3G femtocell services will provide high-speed data access in Japan in early 2009 and are likely to appear in Europe soon after, analysts say.

Can I take one on the road with me?

That depends on where you're going. While they're intended for home use, femtocells can be taken on the road (Sprint's Airave box is about the same size as a standard home router) -- provided you're staying in the US and the wireless carrier offers coverage at the new location.

"The Sprint one uses GPS and won't transmit unless its location is within Sprint's territory and Sprint says 'yes,'" Nogee says -- an assertion confirmed by Sprint's Airave documentation (PDF) . Sprint recommends that you check the ZIP code of the area to which you're traveling to confirm that the service is available there.

What's required for setup?

Femtocell devices require you to have a wired broadband Internet connection, such as DSL or cable; they won't work with satellite or dial-up connections. In addition, you must have an available power outlet and a free Ethernet port on your modem or router. And, of course, you'll need a mobile phone and calling plan with the carrier offering the femtocell service.

Sprint's Airave box requires little setup or configuration; however, it must be located near a window for the GPS feature to work, according to Sprint's Airave documentation (PDF) . The global positioning service "can take up to an hour to locate a satellite," according to Ovum analyst Steven Hartley .

Once set up, how well do they work?

Femtocells repeatedly scan the environment, seeking out the strongest signal to optimize the connection. Independent tests of Sprint's Airave from the likes of Engadget and Slashgear found the signal to be strong and clear in areas that were weak or nonfunctional without Airave. BusinessWeek , on the other hand, found the coverage to be spotty.

Once a connection is established, it won't exceed the maximum data rate of your broadband network, experts say -- something to keep in mind if you plan to have multiple callers using the service simultaneously.

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Femtocells use proprietary security, with a firewall that sits between the caller and the carrier.

Critics of Sprint's Airave have pointed out that the device ships "unlocked" to all Sprint customers -- in other words, anyone with a Sprint phone in range of your femtocell can use your connection. However, the company points out that in most cases, other users would have to be inside your home to be in range of the femtocell. You can also choose to restrict access to the service to up to 50 select phone numbers.

Whether other carriers will make their femtocell devices open to other customers by default remains to be seen.

Will my carrier offer femtocells soon?

Whether we'll see more US carriers join Sprint in offering femtocell service in 2009 remains unclear. Verizon Wireless is "exploring [femtocells'] use but have not committed to rollout plans yet," says Tom Pica, a company spokesman.

AT&T, the nation's largest wireless carrier, remains mum on its vision for femtocells. However, recent reports suggest that the carrier is asking suppliers to submit proposals for developing such a service. Additionally, AT&T is part owner of 2Wire, maker of DSL home gateways. 2Wire recently announced plans to make gateways with femtocell functionality.

If true, the reports wouldn't surprise In-Stat's Nogee, who says AT&T's entrance into femtocells is likely.

As for T-Mobile, although the international venture arm of the company has invested in femtocell manufacturer Ubiquisys, industry watchers say T-Mobile USA is sticking with its Hotspot@Home service , based on Wi-Fi rather than femtocell technology.

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Although femtocells are still in their infancy, a number of manufacturers have announced products supporting the new technology. Samsung Telecommunications America is the manufacturer of Sprint's Airave femtocell, released in 2007. In September 2008, UK-based Ubiquisys was chosen to provide femtocell access points to the first 3G femtocell deployment by Japan's carrier Softbank.

And earlier this year, the US equipment makers Motorola and Netgear unveiled Ethernet gateways that include both femtocell access points and Wi-Fi routers. These devices won't be sold directly to consumers, but to carriers, who will in turn sell them to their subscribers when they roll out femtocell services.

Will femtocells reduce the demand for Wi-Fi?

Not likely, say analysts. Wi-Fi is already well ingrained in home and office networking, and femtocells are becoming part of Wi-Fi routers, not alternatives to them.

"Femtocells and Wi-Fi are complementary," Carlaw says. The analyst sees carriers bundling the two technologies together, with one offering voice support and the other data networking.

What about WiMax?

Femtocells are likely to help, not hurt, WiMax. Players such as Sprint and Clearwire are looking at femtocells as a potential way to avoid costly WiMax buildouts in urban areas. Instead of a larger "macro network" delivering the faster and longer-range wireless signal, home broadband networks could be employed.

Comcast is one of those companies interested in seeing the development of WiMax femtocell base stations. The cable giant is an investor in Clearwire, which along with Sprint is creating the nationwide Xohm WiMax network in the US.

Earlier this month, an Unstrung report speculated that the cable giant will introduce WiMax femtocells during the second half of 2009. Although Comcast hasn't commented on the news, Clearwire has set aside 5 MHz of spectrum solely for femtocells, according to ABI's Carlaw.

What else do I need to know about femtocells?

A number of questions persist, including ownership of the devices, potential interference as femtocells become more common and how carriers will market the technology. The answers could unlock US$70 billion in savings for operators and put an end to the most nagging problem for mobile consumers: making indoor calls.

Ed Sutherland is a freelance writer who has followed the rise and fall of countless technologies over the years.