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FEMTOCELLS AND MOBILE DATA

6/14/2010 4:43 AM Eastern

LAST TIME, WE LOOKED INTO THE BIG NUMBERS THAT CHARACTERIZE
the stuff moving over the Internet — Exabytes, Zettabytes,
Yottabytes.

This week, we’ll look at another set of numbers, used
to define things very small. These are numbers to the left
of zero — nano, pico, femto. (And, after that, atto, zepto,
yocto.)

Why care? In data networking, it’s a symbiotic thing
— the larger the volume of data, the greater the need to
break the network into smaller and smaller coverage areas,
to handle the load.

Why care now? Hello, iPhone 4, with the camera on
the front for wireless video calls. Hello, iPad, with your
video splendor! The glut of chatty, bandwidth-assuming
gadgets at the ends of (AT&T’s) mobile network means
challenges in keeping all the bits flowing in the right direction,
at the right time. It’s not for the faint of plant.

Here’s how Apple CEO Steve Jobs put it, at the “D8”
conference hosted by The Wall Street Journal earlier this
month: “I’m convinced that any other network, if you put
this many iPhones on it, would’ve had the same problems.”

That was a week before the launch of the iPhone 4.

It brings to mind the early “video phones.” Remember?
In the 1980s, you could go to an AT&T store to try it. This
was way before broadband as we know it. Engineers at
the time always recommended a feigned sneeze, to test
the capabilities of the connection. Sneezes aren’t an issue
now (pollen notwithstanding).

Traffic congestion is why AT&T in March launched a
“femtocell” product — a $150 box for the home or building,
marketed as a “mini cellular tower in your home.” In
this case, the “femto” in “femtocell” is more marketing than
actual numbers.

In marketing-speak, the “femtocell” is next in the progression
after the pico cell. Either way, it’s an indoor access
point to make sure you still have five bars of signal in
your building, even if you’re deep within it. In short, the
femtocell is more of a personal cell, while picocells are for
an area.

Femtocells are relatively new, mostly because it’s taken
time to cost-reduce them into an affordable state.

For the people who watch over mobile broadband
bandwidth, femtocells are a part of what one wireless pal
calls “the densification” of the plant — adding more access
points, buttressed with DOCSIS-based backhaul.

The cable angle is in the backhaul. It’s about femtocell
(or picocell) access points, hooked to DOCSIS modems, to
offload the traffic. That Wi-Fi federation of cable companies
on the East Coast, hooked up together so that people
can get a good strong broadband signal, wherever they
are? That’s DOCSIS-based backhaul.

September