Understanding femtocells

Beth Schultz
06 Jan 2011

A femtocell is a small cellular base station that lets mobile operators extend wireless network coverage into homes, and increasingly to businesses, where signals are weak. A handset automatically registers to the femtocell, which in turn connects to the mobile operator’s network via a wireline broadband link. Users can then make and receive voice calls via this Internet connection -- typically DSL or cable -- and the in-dwelling, femtocell-supported cell link.

Industry watchers anticipate femtocell technology use in the US to explode in 2011. In fact, the number of femtocells now actually outnumbers conventional outdoor cell sites, according to Informa Telecoms & Media study conducted on behalf of the Femto Forum. In the October report, Informa placed the number of femtocells in the U.S. at a conservative 350,000, compared to about 256,000 macrocell base stations. The firm estimates at least twice as many femtocells as macrocells will be in use by March 2011.

Femtocell technology use is expected to grow as mobile operators add in support for packet voice calls, differentiate based on applications and push the technology into the enterprise.

The large US cell providers -- AT&T, Sprint and Verizon -- offer femtocells via the respective MicroCell, Airave and Network Extender offerings they’ve rolled out over the last few years. The providers initially used femtocells to support CDMA2000 (also known as CDMA 1X) for voice calls, and that's still their primary use, despite new support for 3G data speeds.

"This is critical technology for addressing coverage in places where users have a hard time getting a voice signal,” said Ken Rehbehn, principal analyst at Yankee Group Research.

Operators have kept relatively quiet about their femtocells, however, mostly offering them only by request to residential customers and largely ignoring the enterprise, Rehbehn added. “Femtocells are a double-edged sword,” he said. “If carriers go to market talking about improved coverage, they risk being positioned as having a lower-quality and less-desirable service.”

One way to overcome this would be to associate femtocell technology with delivery of value-added services, such as NTT DoCoMo has done in Japan. In essence, the carrier offers a presence service for working parents. When a child arrives home, the femtocell senses the arrival of the registered handset and sends an e-mail notification to the parents, providing them peace of mind, Rehbehn said.

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