U.S. moves to protect spectrum
- By Bob Brewin
- Dec 05, 2006
Spectrum management in a global environment and its implication for the Defense Department and national security are key themes of this week's DOD Spectrum Summit in Annapolis, Md. The United States is developing positions and policies for an international conference that will determine spectrum issues and uses.
The International Telecommunications Union (ITU), a United Nations agency, holds a World Radiocommunication Conference (WRC) about every four years to coordinate global frequency allocations and uses with the U.N.'s 191 member countries. The United States has already started to develop preliminary positions and policies for the 2007 WRC, planned for Oct. 22 to Nov. 16, 2007, in Geneva.
The Federal Communications Commission has developed draft recommendations designed to protect portions of spectrum used by DOD and other federal agencies against encroachment from next-generation mobile wireless services.
The FCC WRC-07 Advisory Committee developed the preliminary recommendations in consultation with industry and the National Telecommunications and Information Administration (NTIA), which represents federal agencies' spectrum needs. The recommendations strongly oppose allocation of most of the spectrum bands ITU will consider for next-generation mobile wireless systems, called International Mobile Telecommunications-2000 (IMT-2000).
The WRC-07 agenda includes consideration of the 3700 to 4200 frequency band for IMT-2000 systems. But the FCC advisory committee said that band is widely used by fixed satellite earth stations that could not tolerate interference from IMT-2000 base stations within a range of from 18 to 43 miles.
The Navy uses fixed satellite systems on aircraft carriers and flat-deck amphibious ships to receive wide-band data. The service also uses the systems to distribute weather data to airline pilots and to provide position and location status for truck fleets, the committee's preliminary report states. It recommends that ITU remove consideration of the 3700 to 4200 frequency band for use by IMT-2000 systems.
The committee also recommended against the use of the 410 to 430 MHz band for IMT-2000 systems because this spectrum is extensively used for national security and public safety purposes. The United States uses the 2700 to 2900 MHz frequency band to support aircraft radio navigation, and the committee rejected the use of this band under consideration by the ITU for advanced mobile services because of potential interference problems.
The United States and other countries have deployed a range of land-based, shipboard and aircraft systems in the 3300 to 3650 band, which ITU is eyeing for IMT-2000 systems. But the FCC committee said it is a poor band for such service because of potentially significant levels of interference. The committee also opposed the use of the 4400 to 4940 MHz band for IMT-2000 systems for similar reasons.
In its proposals to the committee, NTIA pushed consideration of the use of high-frequency maritime bands in the 4000 to 9995 KHz range to support advanced digital data systems. The agency said these frequencies can form the spectrum backbone of enhanced maritime and port security systems, which will use the frequencies for ships' automatic identification systems.
Besides dealing with global spectrum allocation issues, DOD also faces the complex issue of developing jammers to counteract radio-activated improvised explosive devices, which continue to plague U.S forces operating in Iraq, without shutting down tactical communications systems. Classified sessions at the spectrum summit Dec. 6 will deal with counter-IED efforts.
The list of speakers and attendees at the summit highlights the importance of spectrum resources to a DOD that increasingly relies on a wide range of this invisible but valuable resource in a network-centric warfare world.
John Grimes, DOD's chief information officer and assistant secretary of Defense for networks and information integration, kicks off the summit with a keynote speech at the first public session Dec. 6. The summit 'will underscore the importance of our community working together to identify and manage the critical spectrum requirements both within the military community as well as those within the broader domestic and international arenas,' Grimes said.
Vice Adm. Nancy Brown, director of command, control, communications and computer systems for the Joint Chiefs of Staff, will follow Grimes' speech with a lunchtime keynote address. Air Force Lt. Gen. Charles Croom, director of the Defense Information Systems Agency, is slated to deliver a wrap-up keynote at a dinner Dec. 7.