At its open meeting last week, FCC commissioners adopted a Notice of Proposed Rulemaking (NPRM) that would allow unlicensed devices to operate in all or part of the 3,650 to 3,700 MHz band at higher power levels than currently authorized under FCC Rules Part 15. Higher power operation would be subject to the devices having safeguards, including "cognitive technology" to protect fixed satellite service (FSS) earth stations in the 3,650 MHz band. The proposed band is adjacent to frequencies used for C-band satellite downlinks - 3,700 - 4,200 MHz.
The FCC FCC News Release announcing the NPRM said, "Fixed unlicensed devices, for example, would be subject to a professional installation requirement and would be prohibited from being located with a defined protection zone surrounding each FSS earth station. Non-fixed, unlicensed devices would be subject to "listen-before-talk" requirements that would detect the presence of any FSS earth station in the vicinity,
and make an appropriate decision of whether to transmit and to make appropriate adjustments to the transmit power. Unlicensed devices would also be required to emit a standardized identification signal which would possibly provide contact information, as well as location."
The FCC said the FSS earth stations using the 3,650 MHz band are primarily located on the east and west coasts, so "this spectrum appears to be a natural fit for service expansion, especially in rural areas." Interference to downlinks operating at 3,700 MHz and above was not addressed in the news release, but may be mentioned in the NPRM, which had not been published on the Internet as of this weekend.
The news release said the NPRM seeks comment on whether other options should be considered, including licensed used of the band by fixed or mobile services or segmenting the band to allow a combination of licensed and unlicensed use.
See the FCC News Release - FCC Begins Rulemaking Proposing to Allow Wireless Broadband Operations in the 3650-3700 MHz Band for some additional information. RF Report will have more detailed information on the NPRM when it is available on-line.
