Third-generation (3G) wireless systems, which could provide much-needed mobile, high-speed access to the Internet and other broadband services, may be able to share certain spectrum that's currently used by several industry and government operators, according to two federal reports released yesterday.
While it's possible to make room for 3G services in the spectrum bands used by the Instructional Television Fixed Service (ITFS), Multipoint Distribution Service (MDS), and Multichannel Multipoint Distribution Service (MMDS), interference issues exist that require further analysis, according to the interim reports. A final report is due to Congress in March 2001.
The companion reports were issued Nov. 15 by the Federal Communications Commission (www.fcc.gov) and the Commerce Department's National Telecommunications and Information Administration (NTIA, www.ntia.gov). The FCC completed an interim report on the 2500-2690 MHz band and the NTIA completed its interim report on the 1755-1850 MHz band.
The reports met their deadline, which was set by President Clinton in October. At that time, the president supported the need to select radio frequency spectrum to satisfy the United States' future needs for mobile voice, high-speed data, and wireless Internet capability. The president directed the Secretary of Commerce to work with the FCC to develop a plan to select spectrum and to determine current spectrum uses and the potential for reallocation or sharing of the bands.
The process will enable the FCC to identify spectrum for 3G wireless systems by July 2001 and then to auction spectrum licenses by Sept. 30, 2002.
The initial technical analysis shows that if 3G systems were to share the same spectrum or channels in any given geographic area, large co-channel separation distances would be needed between 3G systems and incumbent ITFS and MDS systems. Without adequate separation distances, 3G systems would cause extensive interference to incumbent ITFS and MDS systems, according to the reports.
This is true because the 2500-2690 MHz band is either used or soon to be used by ITFS and MDS systems in the most populated areas of the country. There are, however, a few geographic areas where some spectrum is not used by incumbent systems. In areas where spectrum is not yet at full operational capacity, voluntary partitioning between incumbent users and 3G operators may offer some promise of sharing as an interim measure, according to the FCC.
Segmenting the 2500-2690 MHz band to enable 3G mobile wireless systems access to this spectrum also would raise technical and economic difficulties for incumbents, according to the reports.
FCC Wireless Bureau Chief Thomas Sugrue said this week that "it would be very, very difficult to share in those bands." But he also didn't entirely quash the idea and said that the FCC plans a notice of proposed rulemaking by the end of the year on possible bands for 3G use.
Likewise, NTIA Director Gregory Rohde said that the interim report provides only an initial discussion of the impact on those incumbents allocating additional spectrum for 3G services. Other issues, such as potential relocation costs, will be outlined in the final March report, he noted.
The 1755-1850 MHz band now is occupied predominantly by the U.S. Department of Defense, but other federal government users also operate there, according to Rohde.
Key features of 3G systems are commonality of design worldwide; compatibility of services; use of small pocket terminals with worldwide roaming capability; Internet and other multimedia applications; and a wide range of services and terminals, according to the FCC.
3G systems capabilities include the support of circuit and packet data at high bit rates; interoperability and roaming; common billing/user profiles; the capability to determine geographic position of mobiles and report it to both the network and the mobile terminal; and the support of multimedia services/capabilities.
