Home' Technology Review : March April 2014 Contents 21
MIT TECHNOLOGY REVIEW
At a military contest in
Miami, a Google scientist
discusses the future of
What can you tell me about why
Google bought Boston Dynamics and
several other robotics companies?
Nothing right now.
Well, what do you find exciting about
I think setting up these challenges
is a good way to motivate people to
work on hard problems and bring
together the best hardware and soft-
ware to make these machines do
useful tasks. It’s going to take a lot
of hard work to make these robots
achieve the same level of perfor-
mance and agility that humans and
animals have. I think that’s some-
thing to motivate everyone.
Is this technology at an earlier stage
than the self-driving cars at previous
The original DARPA challenge for
autonomous vehicles basically came
down to waypoint following and
GPS, and then of course as it pro-
gressed to the Urban Challenge it
became much more complicated.
[At this challenge], these tasks cer-
tainly may look easy, especially for
a human, but they’re very, very dif-
ficult. You can’t yet buy these robots,
so they’re very much research pro-
totypes. But I feel like in the last 20
years there’s been incredible accel-
eration, and I’m really excited to see
this much effort and attention being
paid to try and make the robots do
— Will Knight
Smart Radios Reduce
Smartphone Battery Drain
The battle between device
makers is moving from software
By David Talbot
The wireless industry faces a fun-
damental problem: more features
and faster data transmission are
draining phone batteries faster than ever.
Fortunately, there’s room for improve-
ment inside the devices, in parts known
as power amplifiers that turn electricity
into radio energy. In phones, these parts
typically consume more power than any
other component and waste
half of it along the way.
Now an effort is under
way to develop power ampli-
fiers that significantly reduce
waste. Eta Devices, an MIT
spinoff based in Cambridge,
Massachusetts, is preparing
a base station module and a
chip that it says not only
decrease battery drain
but work well in high-
for ultrafast technologies.
Existing power ampli-
fiers maintain their voltage at
a fairly high level at all times to
be prepared for peak needs—but this is
wasteful. Newer approaches adjust that
level on the fly, following the “envelope”
of the actual radio signal.
Such “envelope tracking,” or ET, tech-
nologies are the hottest hardware devel-
opment in the mobile-phone industry.
Last fall Qualcomm became the first com-
pany to ship a chip with such technology.
The company says the chip helps lower
electricity consumption by 20 percent
and helps reduce a related problem—
heat generation—by up to 30 percent,
“allowing for longer battery life for end
users, as well as enabling manufacturers
to shrink the size of their devices,” says
Peter Carson, Qualcomm’s senior direc-
tor of marketing.
The difficulty with ET, though, is that
its efficiency plunges at higher data rates.
Envelope trackers often require a rela-
tively large capacitor to store and release
bursts of energy while maintaining
smooth and continuous voltage changes.
Eta Devices takes a radically differ-
ent approach, favoring fast,
abrupt changes with a
smaller capacitor. Mattias
Åström, the company presi-
dent, reaches for an auto-
motive analogy to compare
the two approaches.
is basically a con-
compared to our
he says. “Fuel con-
sumption is always
better when you have a
The chip is now being fabricated for
the first time, but the concept has been
built out for base stations and may be
commercialized this year. The Eta mod-
ule, a little smaller than a shoebox, is the
first 4G LTE transmitter in the world to
achieve average efficiency greater than
70 percent, a big jump from the 45 to 55
percent in currently available technology,
says Eta cofounder Joel Dawson.
2/5/14 5:14 PM
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