The Battle for Bandwidth

Oct. 1, 1999

Pentagon officials call it “the lifeblood of the battlefield,” but they are not referring to fuel, water, food, or any other traditional commodity. Rather, they are talking about the electromagnetic spectrum-the range of natural radiation used by radios, radars, televisions, and the like to send signals over vast distances at lightning speed.

Information systems undergird today’s dominant American military, and anything that threatens access to the spectrum generates immediate and serious concern.

However, the electronic spectrum is a finite resource, and it has become precious. The United States military, as one of the world’s most voracious consumers of the spectrum, increasingly finds itself battling a formidable foe-a spectrum-hungry commercial telecommunications industry eager to expand its range of services and increase profits.

In this war for the spectrum, the stakes are high. The civilian economy has been pitted against the needs of US national security, with the Defense Department fighting on the political and regulatory front to assert its rights to large swaths of the spectrum. Asserting its own claim is a coalition of business interests comprising major satellite, broadcasting, and cellular telephone associations in Washington, D.C.

The commercial sector argues, with considerable success, that its claim to spectrum access is as compelling as that asserted by the armed forces. Its spokesmen maintain that US firms need access to greater and greater portions of the spectrum to foster telecommunications growth and indirectly fuel the modern global economy.

A Crowded Arena

Spectrum issues are complex, involving federal auctions, international regulators, and technical coordination of hundreds of systems operated by users of every imaginable sort. DoD has been forced to square off against social and economic interests as diverse as the American Indian lobby, emergency 911 services, and Africans who want satellite-delivered radio programming.

Few are more familiar with the problem than Col. Richard Skinner, a USAF officer serving in the office of Arthur L. Money, the senior civilian official named to be assistant secretary of defense for command, control, communications, and intelligence. “DoD [realizes] the importance of access to spectrum,” said Skinner. “People want wireless technology. They want multiple phones, [and] wireless computers that operate at high speeds. It is generating tremendous demand for spectrum.”

To no one’s surprise, Congress has become deeply involved in the dispute, with some members lining up behind the Pentagon and others taking the side of commercial business interests.

Hear the words of one senior Congressional staffer who is sympathetic to the DoD cause and involved in spectrum issues on a daily basis: “It’s essential to protect military access to frequencies. … The current process has resulted in short-term fiscal considerations taking priority over national security and led to the long-term loss of taxpayer investment.”

This person warns that, if industry aggressively expands into spectrum bands that are to be shared with the military, then commercial users eventually will complain about interference from the military systems, and the Pentagon will be ordered to stop operating those systems. He pointed out that, in California, civilians forced the Navy to stop using some radars close to the coast. Reason? Aircraft radar signals had the unintended effect of opening garage doors and messing up cordless telephones. Residents complained.

DoD and commercial interests share the spectrum in countless areas. Civilian cellular phones share bandwidth with DoD radar and satellites. Commercial satellites in virtually all bands, in current use and planned for the future, share the spectrum with DoD satellites and military radar. Satellite home television services use the same band as the Pentagon’s new Global Broadcast System.

The Defense Department has “nearly 900,000 spectrum dependent systems,” according to a DoD report to Congress setting out the military’s spectrum requirements. Although many of the details of DoD spectrum usage are classified, systems generally include communications, radar, electronic combat, and navigation. Additionally, spectrum access is needed for training, testing, security, and fire control at military installations.

A single military fighter aircraft will carry many systems dependent on the spectrum. The list could include:

  • Radar altimeter
  • Joint Tactical Information Distribution System
  • Global Positioning System
  • Instrument landing system
  • Fire-control radar
  • Electronic warfare systems for jamming or detection of enemy radars

The range of the spectrum required for one platform is broad. The more systems carried, the more intense the need for the spectrum. As DoD platforms have become more complex to support the need for more mobility and precision in operations, the chance for radio interference with systems has gone up, further complicating the problem of sharing or agreeing to reallocation of the spectrum to commercial users.

Keeping a Distance

As DoD’s report to Congress stated, “Our forces must have enough spectrum to allow multiple systems on multiple platforms to operate on frequencies far enough away from each other to prevent mutual interference.”

More advanced military systems have even higher spectrum requirements. Designing new systems with technological advances to use the spectrum more efficiently, and thereby reduce the need for the spectrum, or to share the spectrum, raises design costs, causing another problem for DoD planners.

DoD’s dependence on the spectrum became clear during the Gulf War in 1991 and in operations in Bosnia in 1995.

“The massive military machine that won the Gulf War could not have functioned without unfettered access to the RF [Radio Frequency] spectrum,” noted DoD’s report to Congress. “Gulf War operations used nearly every major military RF system in the US arsenal.” The report implied that the US moved right away to destroy Iraqi systems that might impede or compete with US use of the spectrum.

Operations like the rescue of downed USAF pilot Capt. Scott F. O’Grady in Bosnia, and subsequent sustained military airstrikes against Bosnian Serb positions, resulted in a sharp upswing in the intensity of US spectrum usage. “The success of [the O’Grady] rescue mission might very well have been [thwarted] without ready access to the spectrum required,” said the Pentagon report. “Future rescue missions will require similar resources.”

More recently, effective spectrum management turned out to be a major challenge in NATO’s military operation in the Balkans. In the view of Skinner, the problem was the sheer number of systems expected to work together. “There are all sorts of opportunities for interference that is unintentional,” he explained, noting that there could be conflicts between two military systems or between a military and a commercial system. Interference occurred during the Kosovo operation, but it was resolved without any serious damage, according to Skinner.

The Pentagon’s attempts to assert dominance on spectrum matters coincide with a boom in the wireless telecommunications industry. Cellular telephones, satellites, and terrestrial wireless services for broadband, Internet, and other uses all are growing at astounding rates. These powerful commercial interests also require new spectrum access to expand, with future growth having a direct impact on the US economy.

What DoD Won’t Say

Industry officials complain that the Pentagon refuses to spell out what it needs in terms of future spectrum assignments. “DoD either won’t tell people, or they don’t know what they need the spectrum for,” said an experienced consultant to several major satellite firms. “It’s problematic for commercial operators to not interfere with them on shared bands.”

GPS and its spectrum assignments are frequently at the center of controversy. In 1997, a block of European countries led by Britain made an attempt to change GPS spectrum allocations, with London proposing to international regulators that some spectrum used by GPS be turned over to commercial use. The move caught Washington off guard, and ultimately Secretary of State Madeleine Albright had to personally intervene to convince the Europeans to back off, according to industry sources.

DoD first became seriously concerned about commercial encroachment on its spectrum in 1993. In that year, Congress decided to auction off spectrum access to commercial users to bring billions of dollars into government coffers. Much of the spectrum made available for auction to the private sector had formerly been allocated to DoD, and the military was forced to move out of some bandwidths.

Doing so has a high cost, said Money. Precisely how much, he could not say. In 1993, it cost the Pentagon between $247 million and $1.2 billion to carry out the spectrum reallocation in the 235 megaHertz area. In another case, a 1997 Congressional reallocation smacked the Pentagon with $436 million to $2.5 billion in unanticipated costs.

Money said DoD and US taxpayers should not have to bear those costs. “There is an essential need to balance the national security needs of the nation with commercial interests when considering spectrum reallocation,” Money contended to Congress. “A national blueprint for future spectrum reallocations could mitigate impacts to the department. For example, if reimbursements of displacement costs were mandated, commercial entities gaining spectrum access would incur the reallocation costs instead of the department and the American taxpayers.”

In testimony to the Senate Armed Services Committee, Money pointed out that spectrum access is essential to gaining the kind of information superiority that wins wars. “Furthermore, there are future threats. Physical threats to the United States are probably going to be more and more low observable. … As the low observable ability of [an] object gets lower and lower, you need more bandwidth to, in fact, detect it.”

Money conceded that new modulation techniques and other technology advances would allow more sharing of the spectrum, but he said that “the department desperately needs [the spectrum allocated to it],” or DoD will incur higher costs and degradation of weapon system performance.

Warner’s Gambit

The issue of sharing, and who would have priority, came to center stage this spring. Sen. John Warner (R-Va.), chairman of the Senate Armed Services Committee, proposed a measure to give DoD priority access to frequency bands in the United States. If approved, the bill would have changed the way the spectrum has been allocated in the US for decades. Today, spectrum allocation is handled by the Federal Communications Commission and the National Telecommunications and Information Administration, with 93 percent of the spectrum between 30 mHz and 300 gigaHertz shared by federal and nonfederal users.

A chorus of loud protests ensued, with opponents charging that Warner’s provision would give DoD a superprimary status in all shared bands where they operate. The commercial companies would have been denied access to some frequencies. For others, the uncertainties about sharing would have discouraged commercial usage. DoD was portrayed as using heavy-handed tactics against the telecommunications industry.

In August, a Congressional conference committee changed the provisions to try to get more cooperation among defense and nondefense spectrum users and eliminated provisions like the one that would have forced commercial firms to pay for interference with military systems. Spectrum sharing and reallocation promises to remain a controversial issue.

“In a lot of bands, DoD is a secondary user,” said Clayton Mowry, executive director of the Satellite Industry Association, part of a coalition of seven commercial associations that protested the move to give DoD favored status. “We think it is critical for any new law to encourage sharing. Legislation that takes away any incentive for DoD to share spectrum or work out interference problems will hurt the development of new commercial satellite systems. Ultimately, we think the Pentagon will become a major user of those commercial satellite systems.”

In the meantime, conflict between military and commercial spectrum users continues to grow. In June, FCC Chairman William E. Kennard wrote to members of Congress opposing the Warner provision that would give DoD more spectrum power. The White House also sent letters establishing the official Administration position as maintaining the status quo in how allocation is managed; it would not give DoD an elevated status.

In the Balanced Budget Act of 1997, Congress called for slicing out and making available at auction another 15 mHz of the federal government’s spectrum. DoD has been asked to give much of the blood in this effort. (A more recent version calls for 12 mHz to be reallocated.)

Actual interference cases also are on the rise.

Overlapping Signals

A dispute has run for many months between WorldSpace, a commercial satellite operator, and the Defense Department. WorldSpace wants to use a three-satellite constellation to broadcast radio programming to billions of people living in poor, remote parts of Africa, Asia, and the Americas. The frequencies chosen by WorldSpace for its broadcasts are essentially identical to those that the Defense Department uses for range telemetry.

WorldSpace has raised more than $1 billion to pay for its fleet of three satellites. One of them, called AmeriStar, would hover in a fixed position above the Western hemisphere and cover the Americas. Some of its beams would cover the US, posing what DoD has deemed as a serious risk to telemetry collection.

WorldSpace operates in the L-band, in frequencies 1467 through 1492 mHz. According to the Pentagon, 86 important flight test centers use the same frequencies to collect data on military and civil aircraft, missiles, and Unmanned Aerial Vehicles. Some 50 programs, including the B-2 bomber, C-17 airlifter, F-22 fighter, Joint Strike Fighter, and Global Hawk UAV would be affected.

“Billions of dollars in delays are likely as programs reconfigure and reschedule telemetry use,” charges a Pentagon assessment of the problem.

DoD has broken off negotiations with WorldSpace after failing to reach an agreement to “deconflict” the spectrum usage, and WorldSpace’s AmeriStar satellite has been placed in storage until a technical solution can be reached that will not interfere with the military operations.

Kennard, the FCC chairman, and the Defense Department also clashed over spectrum access that Kennard wanted to use to bring better telecommunications service to Indian reservations in the American southwest. In pursuit of that goal, Kennard wanted to use a fixed wireless spectrum band, 3400-3700 mHz, but it is already used by the Air Force’s E-3 Airborne Warning and Control System aircraft radar and various Navy radars.

Kennard wanted DoD to share the spectrum. Skinner, the Pentagon official, said DoD agreed to an experimental license to demonstrate a system to a limited number of terminals. However, Nortel, a big telecom firm, has asked for frequency allocation to serve far more than the initial 200 terminals. The service no longer looks temporary or experimental to the Pentagon, and DoD, according to Skinner, “has to go back, analyze this, make a judgment, and decide based on technology and policy whether the license ought to be granted.”

The concern is simple enough. “Eventually,” said Skinner, “you get pushed out of the bandwidth. Every time AWACS flies and someone’s telephone doesn’t work, it will generate a lot of complaints, even though we are primary users [of that particular frequency].”

A new emergency service called E911, which lets the rescue personnel know where a caller is, would incorporate Mobile Satellite System and GPS satellite receivers into the same equipment. Skinner said as long as the low-powered GPS signals aren’t overpowered by noise from the nearby MSS bands, this initiative would be great. Commercial global mobile telephone handsets from Iridium and Globalstar will operate at a frequency just above GPS, which did bring up military concerns of interference, but they seem manageable.

Ultrawideband Radar

More recently, a technology called ultrawideband radar, a low-powered radar that has found a use in commercial systems, has raised concerns about interference with GPS signals. Ultrawideband radar is used for detection and ranging, but in the most simple terms, it has found its way into a stud finder device to help carpenters and homeowners to determine the precise location of two-by-four studs in walls by locating nails hidden in covering wallboard.

Skinner said the technology and devices are new and unlicensed, and a debate has begun about what might happen to GPS signals when a large number of them are being used, covering a lot of the bandwidth.

The loss of spectrum access and the lack of standards are some of the most pressing issues facing DoD as it prepares to fight in a modern day digitized military engagement, said Mary Ann Elliott, president and CEO of Arrowhead Space and Telecommunications, Inc., of Falls Church, Va. “The loss of spectrum impacts [DoD] investment in equipment and technology which they have today and will have a major impact on future budgets which must meet the costs of replacement telecommunications equipment. The lack of standards and interoperability between the numerous proposed broadband systems will create havoc in the future.”

Skinner said that he expects to see additional commercial attempts to raid the areas of the spectrum currently used by DoD. Notably, the next-generation cellular telephone, being developed under an initiative known as IMT-2000, needs a large chunk of continuous spectrum on a worldwide basis, and either broadcast or military radar frequencies could be targeted for use.

Skinner warned, “The competition for spectrum will be keen, and we need to figure out how to protect national security and critical services. We will have to migrate some services to a higher frequency, but that is not a panacea. … We will try to cooperate, but in cases where we don’t have an alternative, where the cost is high to move to another part of the spectrum, or where there’s a high impact on users, we will make clear … the kind of damage spectrum allocation will do.”

The Spectrum, in Brief

Visible light is one form of electromagnetic radiation. Others types include radio waves, microwaves, infrared radiation, ultraviolet rays, X-rays, and gamma rays. Collectively, these forms of radiation make up what is known as the electromagnetic spectrum.

These components of the spectrum have a basic similarity: All travel at 186,000 miles per second-the speed of light. What makes each unique is its wavelength, which is directly related to the amount of energy that the waves carry. The shorter the wavelength, the higher the energy.

The colors in visible light represent only a very small portion of the total spectrum. On one end are radio waves whose lengths are billions of times longer than those of visible light radiation. On the other end of the spectrum are gamma rays. These have wavelengths millions of times shorter than those found in visible light.

Conflict on the Electromagnetic Spectrum

Military Uses Competing Uses
4400-­4990 mHz
fixed wideband communications

mobile wideband communications

command links

data links

fixed satellite service

general wireless communications

public safety

3100-3650 mHz
high-power mobile radars

shipboard air traffic control

missile links

airborne station keeping

multipoint distribution system

wireless local loop

fixed satellite service

2200-2290 mHz
guided missile telemetry

DoD satellite tracking, telemetry, command

point-to-point microwave

personal communications system

wireless local loop

multipoint distribution system

1755-1850 mHz
point-to-point microwave

DoD satellite tracking, telemetry, command

air combat training systems

tactical communications

tactical data links

personal communications system

multipoint distribution system

1435-1525 mHz
telemetry supporting aerospace industry digital audio broadcast, land

digital audio broadcast, satellite

Mobile Satellite System

1215-1390 mHz
long-range air defense

medium-range air defense

radio navigation

air route surveillance radars

tactical communications

test-range support

air and fleet defense

drug interdiction

Global Positioning System

remote satellite sensors

nuclear detection

Mobile Satellite System

Global Positioning System

general wireless communications

wind profiler radars

420-450 mHz
ballistic missile surveillance radars

ballistic missile early warning radars

shipboard early warning radars

airborne early warning radars

missile flight termination

air vehicle flight termination

air vehicle command links

troop position location

anti-stealth radar

foliage penetration radar

auxiliary broadcast

commercial mobile radio service

biomedical telemetry

wireless local loop

400.15-401 mHz
Defense Meteorological Satellite Program Mobile Satellite System
225-400 mHz
tactical air data links

tactical air/ground data links

satellite communications

military air traffic control

search and rescue

executive communications

tactical communications

little Low Earth Orbit satellites

public safety

digital audio broadcast, land

commercial mobile radio service

138-144 mHz
tactical air data links

tactical air/ground data links

land mobile radio

little LEO satellites

public safety

Theresa Foley, a freelance writer living in Florida, is a former editor of Space News. Her most recent article for Air Force Magazine, “Commercial Spacefarers,” appeared in the December 1998 issue.