scale solutions, and we constrain what each network can do to
optimize its performance,” he adds. Over the past two decades,
efforts to overcome this limit using current mobile networking
technology have been largely unsuccessful.
By comparison, Rich says, commercial Internet service
providers (ISPs) can deliver mobile broadband connectiv-
ity to thousands upon thousands of users. “When Verizon
adds a new customer, it doesn’t impact a user in Kansas,” he
explains. To accomplish this task, ISPs use a pre-installed
infrastructure that primarily is based on high-speed fiber
optic cable networks combined with clusters of digital wire-
less radio transceivers that employ cellular spread-spectrum
technology. The cellular telephone industry acknowledges
that aspects of this infrastructure are reaching their own
limits in terms of the number of users that can be supported
with current digital cellular technology, and research is
underway to overcome those limitations (SIGNAL Magazine,
“MultiAntenna Research...,” December 2012, page 49).
The DARPA RFI seeks input from researchers in the mili-
tary, government, academic and private research lab sectors in
three primary areas: fundamental understanding of the limits
of current networking technology; ways to modify the use of
MANETs to improve service to warfighters; and improved
methods of delivering networking technology.
For a look back at the future,
visit SIGNAL’s searchable
online archives at
All articles published in SIGNAL since
January 1999 are available for viewing and
can be e-mailed directly from the site.
“We’re trying not to do a
program that builds upon
an existing capability,
whether that’s military of
commercial. We’re trying to
find what may be new and
different, a new approach.”
—Mark Rich, program manager,
DARPA Strategic Technology Office.
The RFI is a clean-slate approach to finding innova-
tive technologies and techniques to overcome limits on
MANETs. “Are there things we could do differently?” asks
Rich. “What are the fundamental limitations on what we
deliver, and who we could deliver it to?” He adds that
DARPA wants to go beyond the status quo and make it pos-
sible to build MANETs around ground-breaking technolo-
gies that could expand capacity by a factor of as much as 20.
“We really want to get a discussion going,” Rich says. “We’re
looking for a breadth of capability and unique insight that
can be used to get the creative juices flowing.”
Rich acknowledges that the RFI might yield a more effective
mobile networking technology developed for commercial ISPs
that could be adapted to the military MANET. “If there is truly
something out there that we haven’t taken advantage of, then
yes, we’d definitely be open to that,” he says. But Rich goes on
to stress that ultimately, the RFI is all about new ways of facili-
tating the use of mobile networking. “We’re trying not to do a
program that builds upon an existing capability, whether that’s
military or commercial. We’re trying to find what may be new
and different, a new approach,” he adds.
Much of the reason MANETs are unable to scale beyond
supporting 50 nodes at a time can be traced to the fact that
so much of the technology is based on technical protocols
developed during the early days of the Internet, or what Rich
calls the wired world. The capabilities are fundamentally dif-
ferent. Wires have much more capacity and less interference.
Compare that, he says, with a military MANET system that is
“We have to deal with a great deal of interference from
ground systems, as well as other [electronic] noise sources in
the local area. And fundamentally, we’re trying to eke out as
much of the fundamental radio capacity as possible for the
delivery of service,” Rich explains. He adds that over the last
several decades, most of those protocols have been fine-tuned
and adapted to MANETs, but they have never been modified
to deal with the realities of wireless data transmission.
DARPA is open to whatever might be proposed, Rich says.
For example, if someone has insights into the basic physics that
govern data transmission over a mobile network and has ideas
that could overcome the current scaling limitations, he would
welcome the opportunity to have authors present their ideas.
He also would like to see papers in the realm of compression,