The U.S. Defense Advanced Projects Agency (DARPA) and an industry partner are preparing for what is being touted as the largest test yet of technology that would greatly expand the radio spectrum available to military users by rapidly identifying and switching to temporarily idle frequencies.

Radios featuring this technology could begin to appear in military operations later this year, according to Marc McHenry, founder and chief executive officer of

Shared Spectrum Co. of Vienna, Va.

The technology to make better use of radio frequency spectrum is being developed under



Generation, or XG,

communications program. DARPA chose Shared Spectrum in 2005 over Raytheon Co. and Lockheed Martin Corp. to continue working on

the technology under a $19 million contract that wraps up in April.

DARPA Director Tony Tether told the House Armed Services terrorism, unconventional threats and capabilities subcommittee

March 21 that while the radio frequency spectrum is generally cluttered, large swaths of bandwidth

often go unused at different times and places.

The XG effort is intended to take

advantage of that unused spectrum, which could lead to a 10-fold increase in spectrum availability, Tether said.

The program features software

that analyzes spectrum and uses

algorithms to determine if troops can broadcast in frequencies

in a particular area without interfering with those

already assigned to the band. The radios can sense interference and then leap to

a new frequency, where they will communicate for as long as it is


according to McHenry, who

led DARPA’s research in this area prior to founding Shared Spectrum.

In addition to making more spectrum available, the XG effort could help address the problem of enemy jamming, Tether said in his testimony. The radios’ ability to determine which frequencies are

in use and hop

to unused bands also could cut down on what some Pentagon officials say is the bigger problem of

unintentional interference by

friendly forces


McHenry said.


still are being developed, but the upcoming test

likely will involve

up to 25 radios, McHenry said during a Dec. 20 interview. Prior demonstrations


transmissions from an unmanned aerial vehicle to the ground this past fall at the Loring Commerce Center, a former U.S. Air Force

base in Maine, and from a U.S. Navy ship to shore during the Trident Warrior exercise off

Virginia this past March, he said.

As part of the DARPA contract, Shared Spectrum is

working to incorporate its technology into radios supplied by

Harris Corp. of Melbourne, Fla., and Thales Communications

Inc. of Clarksburg, Md., for the experiment.

The company envisions

licensing its technology to those firms and other radio manufacturers, McHenry said.

Shared Spectrum also is

talking with

the U.S. Army and U.S. Marine Corps about the possibility of a follow-on contract to equip Thales and Harris radios with the software for operational use, according to Sal D’Itri, director of sales and marketing for Shared Spectrum.

Shared Spectrum might build radios in-house for niche applications like small unmanned aerial vehicles and ground-based robots used

for purposes including bomb inspection and disposal

, D’Itri said. Operators of these vehicles are struggling to get the necessary radio frequency assignments, he said.

For hazardous missions such as bomb disposal, overcoming jamming is especially critical because the inability to communicate with robotic vehicles would force people to put themselves in harm’s way, D’Itri said.


currently focused on the

military market

, Shared Spectrum


the XG technology could have civil or commercial

uses as well, McHenry said. The company

already is working with the National Institute of Justice, the research and development arm of the U.S. Justice Department, on applying the technology to radios used by public safety officials, he said.

Satellite applications also are envisioned for the technology. McHenry said

Shared Spectrum is

working with another company, which he declined to identify, that has offered to host its technology on a satellite

. Space-based applications include expanding the frequencies available for satellite-to-ground communications as well as identifying zones of available spectrum for radio operators on the ground, he said.