Spectrum Engineering Reports

The availability of the radio spectrum in the United States is critical to over 40 radio services that provide functions ranging from air traffic control to amateur radio operations. Although the radio frequency spectrum is not a consumable resource, the use of a frequency at a given location usually prevents that frequency from being used by others in the same geographic area. This need for exclusive geographic use to preclude harmful interference has led to current spectrum regulations that establish spectrum use rules, such as granting licenses for spectrum use, and partitioning the spectrum for shared use between radio services.

Dedicated short-range communication (DSRC) systems have been proposed for operation at locations across the United States in the 5850- to 5925-MHz band. To establish electromagnetic compatibility between DSRC and other 5-GHz systems, it is necessary to understand current and future occupancy of this spectrum. This report summarizes results of measurements made in 5-GHz spectrum for the Federal Highway Administration (FHWA) of emissions from high-power radars and a fixed satellite service (FSS) earth station.

The Coast Guard plans to operate an Automatic Identification System (AIS) Digital Selective Calling (DSC) based transponder system as part of the Ports and Waterways Safety System (PAWSS) in the lower Mississippi River. The AIS uses two duplex channels for ship-to-shore and shore-to-ship digital data transmissions and a simplex channel for channel management. The duplex channels are identified as AIS working channels. The PAWSS relies on a combination of voice and AIS working channels in the VHF maritime mobile band to provide signal coverage in the vessel traffic service area (VTSA). The proposed coverage area for the VTSA encompasses the Mississippi river starting at river mile 255 to the sea buoy located at Southwest Pass and also includes an area in the Gulf of Mexico for ships approaching the sea buoy. Other waterways such as the Mississippi River Gulf Outlet and the Industrial Canal are also included in the proposed VTSA. A contractor has installed government owned equipment at five tower sites along the river to provide the coverage for both the voice and AIS working channels. Each tower provides coverage for part of the VTSA. Before the system can reach operational status, the coverage of the RF portion of the system must be measured and documented. The Coast Guard funded NTIA to perform coverage tests on the system to examine and evaluate the adequacy of the RF coverage of the channels used for voice and AIS data transmissions. The tests were performed August 4-10, 1999. The results of these tests are given in the following sections of this report.

The Coast Guard funded the National Telecommunications and Information Administration (NTIA) to perform electromagnetic compatibility (EMC) tests between an ITU-R M. 825-3 (Characteristics Of a Transponder System Using Digital Selective Calling Techniques for Use with Vessel Traffic Services and Ship-to Ship Identification) based Automatic Identification System (AIS) operating on 12.5 kHz channels and Public Correspondence (PC) Systems operating on 25 kHz channels. The tests were performed between January 17-28, 2000 in and around an AIS base station communications tower located at Point Ala Hache, La. by NTIA, SETA Corporation, and Coast Guard personnel.

The National Telecommunications and Information Administration (NTIA) is the Executive Branch agency principally responsible for developing and articulating domestic and international telecommunications policy. Accordingly, NTIA conducts studies and makes recommendations regarding telecommunications policies and presents Executive Branch views on telecommunications matters to the Congress, the Federal Communications Commission (FCC), and the public. NTIA also serves as manager of the Federal Government's use of the radio frequency spectrum. President Clinton signed an executive memorandum dated October 13, 2000, that stated the need and urgency for the United States to select radio frequency spectrum to satisfy the future needs of the citizens and businesses for mobile voice, high speed data, and Internet-accessible wireless capability; the guiding principles to be used for the development of third generation (3G) wireless systems; and the direction to the Federal agencies to carry out the selection of spectrum. The President directed the Secretary of Commerce, in cooperation with the FCC, to issue interim reports by November 15, 2000 describing the current spectrum uses and the potential for reallocating or sharing the bands identified at the International Telecommunication Union (ITU) 2000 World Radiocommunication Conference (WRC–2000) for 3G wireless systems. The FCC, in conjunction with NTIA, is expected to identify spectrum by July 2001, and auction licenses to competing applicants by September 30, 2002. In response to the President’s memorandum, this interim report provides an examination of Federal operations in the1755–1850 MHz band, and a discussion of the potential for accommodating 3G, advanced mobile telecommunications systems in the band.

Recent advances in microcircuit and other technologies have allowed the use of very narrow pulses (typically less than a nanosecond) with very wide bandwidths in new applications in both radar and communication devices. These devices, called Ultrawideband (UWB) devices, may have instantaneous bandwidths of 25 percent or more of their center frequency. They are capable of locating nearby objects and can use processing technology to “see through walls” and communicate in multipath propagation environments, which makes them useful in many commercial and government applications. The developers of UWB devices, because of their low output power, low manufacturing cost, and anticipated wide marketability are seeking authorization from the National Telecommunications and Information Administration (NTIA) and the Federal Communications Commission (FCC) to operate UWB systems on an unlicensed basis.

On behalf of the Secretary of Commerce, the National Telecommunications and Information Administration (NTIA) has prepared this report to the President and the Congress as required by Title X of the National Defense Authorization Act for Fiscal Year 2000 (NDAA-2000). NDAA-2000 requires NTIA to convene an interagency review and assessment of certain spectrum reallocation issues in coordination with the Chairman of the Federal Communications Commission (FCC) and with Federal executive agencies via the Interdepartment Radio Advisory Committee (IRAC). The review includes: 1) Progress made in implementation of national spectrum planning; and 2) The spectrum reallocations made in accordance with the Omnibus Budget Reconciliation Act of 1993 (OBRA-93) and the Balanced Budget Act of 1997 (BBA-97), and the resulting implications to Federal executive agencies.

This report provides an assessment of electromagnetic spectrum reallocation from Federal to private-sector use in accordance with requirements of Title VI of OBRA-93 and Title III of BBA-97. The report, addressing progress in national spectrum planning, implications of past spectrum reallocation actions, and anticipated impact of future potential reallocations, was prepared in coordination with affected Federal agencies, and the FCC. As directed by NDAA-2000, the assessment focused particular attention on impacts of such reallocations on military capabilities, civil space programs, and Federal public safety systems.

The study described in this report was undertaken by the National Telecommunications and Information Administration (NTIA) in response to a Federal Communications Commission (FCC) Notice of Proposed Rule Making (NPRM) concerning the operation of a new class of spectrum dependent devices, designated as ultrawideband (UWB) devices under the FCC’s rules and regulations in Part 15 of Title 47 of the Code of Federal Regulations (CFR). This NPRM raises a number of questions and concerns regarding the electromagnetic compatibility (EMC) of the proposed UWB transmitting devices to those spectrum-dependent systems currently in operation. The NTIA, as the Executive Branch agency principally responsible for developing and articulating domestic and international telecommunications policy affecting Federal Government spectrum users, is particularly interested in the potential for interference to telecommunications infrastructure utilizing Federal Government spectrum for critical and/or safety-of-life functions, many of which operate in spectrum designated as the “restricted frequency bands.” These frequency bands have been designated as restricted because the systems operating in them provide critical safety functions. Before NTIA can agree to emissions from UWB devices in restricted frequency bands used by critical Federal Government radiocommunication systems, it must ensure that there is no potential interference introduced from their proposed operations. The Global Positioning System (GPS) is an example of a critical radio navigation system that operates in several of the restricted frequency bands.

The President signed an executive memorandum dated October 13, 2000, that stated the need and urgency for the United States to select radio frequency spectrum to satisfy the future needs of the citizens and businesses for mobile voice, high-speed data, and Internet-accessible wireless capability; the guiding principles to be used for the development of third generation (3G) wireless systems; and the direction to the Federal agencies to carry out the selection of spectrum. The President directed the Secretary of Commerce to work cooperatively with the FCC to develop a plan to select spectrum for 3G wireless systems, and to report on the current spectrum uses and the potential for reallocation or sharing of the bands identified at the International Telecommunication Union (ITU) 2000 World Radiocommunication Conference (WRC-2000) that could be used for 3G systems.