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.
The 1710-1885 MHz and 2500-2690 MHz bands were two bands, among others, identified by the WRC-2000 as additional bands for 3G mobile systems, also called International Mobile Telecommunications-2000 (IMT-2000). The United States is planning for the introduction of IMT-2000 services by commercial providers, but unused spectrum to accommodate such services is currently not available. Both NTIA and the FCC are examining these candidate frequency bands (1755-1850 MHz and 2500-2690 MHz, respectively) identified by the conference that are under their respective jurisdictions, with a view towards accommodating IMT-2000 systems. NTIA and the FCC are issuing separate interim reports addressing the accommodation issues in the bands identified, and will issue final reports at a later date. Since the WRC-2000 identified these candidate bands for IMT-2000 operations, promoting worldwide harmonization of spectrum is a desired long-term goal.
In addition to the above two bands identified by the conference, other bands that could be considered in the United States are: 698-746 MHz, 747-762 MHz, 777-792 MHz, 806-960 MHz, 1850-1990 MHz, and 2110-2150 MHz.
The 1710-1755 MHz band will be transferred to the FCC in 2004 on a mixed use basis pursuant to the requirement of the Omnibus Budget Reconciliation Act of 1993, but Federal operations can remain in 17 protected areas. The 1850-1885 MHz band is under FCC regulatory jurisdiction and is currently used for personal communications services (PCS). The remaining 1755-1850 MHz band, which is the focus of this study, is under the jurisdiction of NTIA. Within the United States, the 1755-1850 MHz band is allocated on an exclusive basis to the Federal Government for fixed and mobile services. Footnote G42 to the National Table of Frequency Allocations provides for the co-equal accommodation of Federal space command, control, and range and range-rate systems for earth station transmission in the 1761-1842 MHz band. The Department of Defense (DOD) is the predominant user of the 1755-1850 MHz band. However, other Federal agencies operate extensive fixed and mobile systems in this band throughout the United States.
The Federal use of the 1755-1850 MHz band can be categorized into several broad classes of systems, 1) tracking, telemetry, and control for Federal space systems, 2) medium-capacity, conventional fixed microwave communications systems, 3) military tactical radio relay radios, 4) air combat training systems, 5) precision guided munitions, 6) high resolution airborne video data links, and various other aeronautical mobile applications, and 7) land mobile video functions such as robotics, surveillance, etc. This interim report specifically addresses the first four classes, but potential accommodation of IMT-2000 systems in the 1755-1850 MHz band must address all classes of systems, each of which involves unique sharing, relocation, reimbursement, and time line issues.
To aid in NTIA's evaluation of accommodating IMT-2000 services in the 1755-1850 MHz band, the DOD provided NTIA an initial report that detailed the electromagnetic compatibility (EMC) between major Federal systems in the 1755-1850 MHz band and IMT-2000 systems.
The EMC analyses showed the most serious challenges in accommodating IMT-2000 systems are related to sharing with the Federal Government uplink satellite control systems, the military radio relay systems, and the air combat training systems. These analyses have shown that the uplink satellite signal margins would be severely degraded by the aggregate IMT-2000 transmissions. Therefore, with regard to possible near- term use of the band for IMT-2000 systems, sharing considerations with the satellite control systems presents a fundamental go/no-go decision, since near-term replacement or changing frequencies in orbiting satellites is not possible. All DOD satellites use receivers that are set to specific channels and cannot be re-tuned after launch. The lifetimes of these satellites can exceed 10 years. Uplink sharing is further complicated by the fact that remote tracking stations must support global coverage of Federal satellite assets in all orbits, and deployable satellite control Earth stations are operated at deployed locations when necessary to accomplish the satellite control mission.
Conventional fixed systems are also a cause for concern because of their widespread use, but NTIA is developing rules for private sector reimbursement for relocating these systems currently operating in the 1710-1755 MHz band to other frequency bands, similar in some respects to the procedures used in clearing the commercial PCS band. These same procedures could also be used as a basis for reimbursement for the relocation of Federal systems, where necessary, from parts of the 1755-1850 MHz band.
The EMC analyses further indicated that the extensive use of the 1755-1850 MHz band by Federal entities, coupled with the projected build out of IMT-2000 systems, would make uncoordinated sharing with IMT-2000 systems infeasible. However, if restrictions on IMT- 2000 operations in space or time prove feasible and under the conditions that (1) IMT-2000 operators reimburse Federal operators to relocate or retune convention fixed and various other systems prior to IMT-2000 operations commencing in the vicinity of the affected Federal operations, and (2) major Federal functions are not impacted, sharing might be possible. One such sharing approach would be to segment the 1710-1850 MHz band into three segments, 1710-1755 MHz, 1755-1805 MHz, and 1805-1850 MHz. This segmentation might make up to two, 45 MHz segments available for IMT-2000 services, under certain conditions. In this approach, mobile (handset) IMT-2000 units would share and transmit in the 1710-1755 MHz segment, the Federal Government would retain exclusive use of the 1755-1805 MHz segment, and the IMT-2000 base stations would share and transmit in the 1805-1850 MHz segment. IMT-2000 operators would coordinate their operations within protection areas, defined by separation distances from major Federal systems required to reduce mutual interference to an acceptable level. However, since both mobile and base stations transmit (and receive) in the 1710-1850 MHz band, simultaneous coordination of two frequencies may be necessary. These factors, plus sharing satellite control uplinks with IMT-2000 base stations, may preclude sharing under these conditions.
A second segmentation option would provide for IMT-2000 mobiles to share and transmit in the 1710-1790 MHz range, in phases, with the base stations transmitting in frequency bands above 2110 MHz. The Federal Government would retain exclusive use of the 1790-1850 MHz segment. This segmentation option would have three phases, the first phase allowing IMT-2000 mobile operations to share in the 1710-1755 MHz band, then adding shared use in the 1755-1780 MHz band, and finally in the 1780-1790 MHz band, if required. As described above, IMT-2000 operators would coordinate their operations within protection areas, defined by separation distances from major Federal systems that would reduce mutual interference to an acceptable level. IMT-2000 operators would also reimburse Federal operators to relocate, modify, or retune conventional fixed and various other systems, and DOD essential military capabilities must be maintained. This segmentation option presents greater flexibility than the in-band segmentation option, from an interference standpoint, because only half of the IMT-2000 system needs to be coordinated, and IMT-2000 base stations would not operate co-channel with satellite control uplinks. If further analysis determines that co-channel sharing with mobiles is feasible, satellite control uplinks would share with IMT-2000 mobiles in the 1761-1790 MHz band. This option could, in the long-term, make up to 80 MHz available for mobiles in the 1710-1790 MHz band to be paired with equivalent spectrum in a higher frequency band.
The alternatives to sharing would be for IMT-2000 services to be implemented in other frequency bands, or, Federal systems in the band segments required for IMT-2000 to be relocated to comparable spectrum. To evaluate options associated with possible relocation of Federal systems to alternate frequency bands, an examination of relocation costs, operational impact, and time schedules for moving must also be considered. This information will be available at a later date and will be included in subsequent reports. In implementing any of the options involving band segmentation, many Federal systems in the 1755-1850 MHz band may need to be either relocated to different frequency bands or modified to operate in the remaining portions of the band, and would be compensated in accordance with the compensation provisions of the National Telecommunications and Information Administration Organization Act (47 U.S.C. 923(g)(1) as amended by the National Defense Authorization Act (NDAA) for FY 1999, requiring compensation to affected Federal entities. Further, for the relocation of DOD systems, the NDAA for FY 2000 requires the NTIA and FCC to identify alternate frequency bands, subject to acceptance by the Secretary of Defense and the Chairman of the Joint Chiefs of Staff, for those affected DOD systems and that such alternative band or bands provide comparable technical characteristics to restore essential military capability that will be lost as a result of relocation. Compensation also applies for modification of all affected Federal systems. Specific compensation procedures are under development and will be released by NTIA at a later date.