Canadian spectrum regulators may find it difficult to come to some spectrum harmonization arrangements with the U.S., particularly in the 1700 MHz band. According to a recent National Telecommunications and Information Administration (NTIA) report the use of that band for future 3G services prove to be much more difficult that previously anticipated. The following is an edited excerpt of the executive summary of the Federal Operations in the 1755–1850 MHz band: The Potential for Accommodating Third Generation Mobile Systems, released November 15. The United States is planning for the introduction of IMT-2000 services, but unused spectrum to accommodate such services is currently not available. Both NTIA and the FCC are examining the1755-1850 MHz and 2500-2690 MHz bands, with a view towards accommodating IMT-2000 systems. To aid in NTIA’s evaluation of accommodating IMT-2000 services, the Department of Defense (DOD) provided 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 3G frequencies. 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. 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 infeasible. However, if restrictions on 3G prove feasible and under the conditions that (1) IMT-2000 operators reimburse federal operators to relocate or retune systems prior to launch of IMT-2000 systems, and (2) major federal functions are not affected, 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, handsets 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 base stations would share and transmit in the 1805-1850 MHz segment. 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 3G 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 presents greater flexibility than the in-band segmentation option, from an interference standpoint, because only half of the system needs to be coordinated, and base stations would not operate co-channel with satellite control uplinks. 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. The full report is available at the NTIA website, http://www.ntia.doc.gov.