What about security?
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 U.S. 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.
Who else is on board the femtocell train?
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, U.K.-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 U.S. 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 U.S.
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 $70 billion in savings for operators and put an end to the most nagging problem for cellular consumers: making indoor calls.
Ed Sutherland is a freelance writer who has followed the rise and fall of countless technologies over the years.