By
Bob Brewin
As my colleague Katherine McIntire Peters wrote in a prescient article in November 2002, what "oxygen is to life, the radio frequency spectrum is to modern living."
This valuable resource is the lifeblood for gadgets and gizmos that we all take for granted, from the cell phones used incessantly by seemingly every 12-year-old in the country (what happened to band practice?) to microwave ovens to satellite television systems devoted to beaming hundreds of cooking channels to the parents of those 12-year-olds.
But, as Peters pointed out, spectrum is as finite a resource as real estate on the island of Manhattan, and growing demands for it threatened national security. Or, as the debate at the June 2003 International Telecommunication Union's World Radio Conference -- a gathering that decided how spectrum should be allocated globally -- illustrated, what's more important: more channels for Wi-Fi or radars operated by the U.S. military?
The conference compromised on this issue, allocating more channels for Wi-Fi, but with a technical fix that ensured folks could not wirelessly surf the Internet if their signals interfered with radars.
Peter's warning on spectrum was followed by a Government Accountability Office report in April 2003 that emphasized "radio frequency spectrum is critical to the development and operation of a variety of military systems such as radars, radios and satellites."
That report added, "More and more military systems depend on spectrum to guide precision weapons and obtain information superiority. . . . In recent years, demand for spectrum, increased with advances in commercial technology . . . [which] has led to competition between government and nongovernment users, [makes] spectrum management vital to prevent harmful interference and to promote spectrum efficiency."
But, GAO reported, spectrum management seemed almost an afterthought in development of billion-dollar systems that would end up as high-priced boat anchors without access to spectrum, because the architects did the needed work on spectrum in later, rather than earlier, stages of development.
Fast Forward
Despite these warnings, it appears that managers of major weapon systems programs, such as the Army's $160 billion Future Combat Systems project, continue to treat spectrum and frequency requirements as something they could get around to later. But, as the Congressional Research Service reported in May, ignoring spectrum requirements threatens grand ambitions. "There is a near-term concern that spectrum limitations could have a significant operational impact on FCS, which is heavily dependent on continuous and near real-time data from a variety of sources for not only its effectiveness but its survivability on the battlefield," the report noted.
Spectrum challenges have grabbed the attention of the Senate and House Armed Services committees, which told Defense to conduct a review of current and future bandwidth requirements for all systems during the next 10 years.
Spectrum management also has gained new visibility and clout with the Defense Information Systems Agency's Defense Spectrum Organization. Paige Atkins, DSO director, told me that it is "absolutely essential [Defense] consider spectrum management issues" when developing systems.
Atkins added that planning should be done globally, as spectrum rules in other countries determine whether or not a Defense system can operate there. Atkins understands the pressure Defense faces to turn over its spectrum to commercial users and it needs to develop technologies to dynamically share spectrum. Specifically, instead of a device being assigned just one frequency, Defense can find unused frequencies and piggyback on that spectrum, even for a matter of seconds, before another transmission starts.
This sounds like a project that will require a lot of really smart algorithms.
The 15-Year JTIDS Delay
The problems Defense faces in finding frequencies to support systems deployed globally are best illustrated by the Joint Tactical Information Distribution System, which has struggled for 15 years with a bum frequency allocation, according to a briefing by Air Force Lt. Col. Aaron Leong.
The system was intended to serve as the data link to connect a variety of Defense weapons systems, including planes and ships, but JTIDS was developed in an occupied band that aeronautical navigation systems worldwide use, according to Leong's briefing, which he presented at the annual DISA customer partnership conference last month.
Bob Gabel, director of Data Link Solutions, a Rockwell Collins/BAE Systems joint venture that sells JTIDS gear to 40 countries, told me this means using specific frequencies requires approval in any country JTIDs is deployed. As Leong pointed out, any use has to be on a non-interference basis.
Gabel said a frequency remap program would help resolve some of the spectrum conflict problems by reducing the number of frequencies used by JTIDS in the near term. Advanced waveforms such as Tactical Targeting Network Technology eventually will replace the Link 16 frequency hopping technology JTIDS uses, "but that is years or decades away," he said.
The Global Hawk and Predator UAV Problem
Leong's briefing also singled out the Global Hawk unmanned aerial vehicle as another key Defense project suffering from spectrum problems. He said the department cannot certify the Global Hawk satellite communication data link and the Global Hawk must operate in a non-exclusive, commercial fixed satellite service band on a non-interference basis.
Jeff Chiocchio, an engineering director at satellite operator Intelsat General, said the Global Hawk transmits data to Ku-band commercial satellites and causes problems because it has a small antenna (1.2 meters in length), which results in the transmission of a wide aperture signal that can cause interference with other satellites just two degrees removed in geostationary orbit.
The Predator UAV, widely used in Iraq, causes similar problems because it has a smaller antenna -- just 0.76 meters. Chiocchio said this interference has not knocked out a satellite transponder and added Intelsat works with its customers to mitigate the interference.
The $1.2 Billion B-2 Bomber Spectrum Bill
The B-2 bomber originally was designed with a radar system that operated in a portion of the Ku-band that satellite TV companies used. Leong estimated that the cost of shifting the radar operation to another band, which requires extensive redesign work, would cost $1.2 billion, or $60 million for each of the 20 B-2s the Air Force operates.
Atkins told me the programs Leong highlighted in his presentation had a historical precedent; they were all singled out by the GAO in its 2003 spectrum report.
It seems Defense still has some spectrum lessons to learn.