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FEMTOCELLS
In June 2008, it was reported that SFR would launch
femtocell service within months. Yet in a follow-up
interview, Thierry Berthouloux, SFR's network solutions
director, said: "We have decided to extend that assessment
period and have put this process on hold to give equipment
suppliers time to consolidate roadmaps. There's no point
making a decision today."
COVERAGE? VOICE? OR MORE?
While the
technology and standards issues are being resolved quickly,
there continue to be varying opinions regarding the
underlying drivers for a femtocell-based service. Clearly
the most addressable option is coverage improvement.
Femtocells are simply lower-cost picocells, optimized for
filling in coverage gaps throughout a region.
However, some believe that if femtocells are deployed
simply for coverage, the true potential of the technology
will not be reached.
"From a technological standpoint, [femtocells']
better in-building coverage for technologies such as WCDMA
and HSDPA is an incredibly important aspect of service
delivery," notes ABI Research Principal Analyst Stuart
Carlaw. "On a conceptual basis, femtocells allow carriers to
price cellular data services in the home aggressively, with the
ultimate goal of shaping consumer behavior."
Sprint's Airave offer delivers improved coverage as well
as a `cheap voice' service. A recent survey of European
consumers indicated that 40% of respondents would
`definitely' or `probably' make a femtocell purchase in
the next 12 months to receive benefits such as `improved
coverage' and `lower cost in-home voice charges.'
"This Pent up demand for a femtocell-like product
does not only start and finish with voice services," Carlaw
explains. "The survey clearly outlined that there is significant
opportunity to link the handset into the connected home
concept that leverages rich multimedia services, as well as
voice."
3G OR LTE?
But not everyone is convinced that 3G
femtocells are a significant growth opportunity. Dean
Bubley, principal analyst and founder of Disruptive
Analysis, sees femtocells biding time until LTE, the next
generation all-IP access network.
"We'll see them [3G femtocells] in niche markets first,
such as rural areas with lots of cable and DSL but poor
mobile coverage," says Bubley.
He thinks mass uptake won't happen until the mobile
networks move on. "LTE was designed with femtos
in mind," he said. "With 3G, femtocells have to be
retrofitted, but with LTE things needed by femtocells, like
cell registration and closed user groups, are all built into
standards up-front."
Regardless, it's clear that small femtocells will have a
giant impact on the mobile network.
Figure 1: Network diagram of 3GPP Home Node B Architecture
10
UMA TODAY
FALL 2008
Standard
3G Handset
Macro Radio Access Network
HNB Access Network
lu-b
lu-h
Internet
lu-cs
lu-ps
lu-cs
lu-ps
Home NodeB (HNB)
(a.k.a. Femtocell)
Node Bs
HNB Gateway
(a.k.a. Femto Gateway)
Radio
Network
Controller (RNC)
HNB
Mobile Core
Network
Circuit, Packet, and
IMS-based Services
HNB GW