NTIA clears path for spectrum sharing in weather satellite downlink band

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The National Telecommunications and Information Administration says it reaffirms an earlier conclusion, although through a different methodology, that government-licensed spectrum in the 1695-1710 megahertz band can be shared with wireless broadband commercial operators.

The NTIA identified in November 2010 the 15 MHz swath of spectrum as a likely candidate for fulfilling in part President Obama's pledge to free up 500 MHz of spectrum for wireless  purposes over a decade.

In a Feb. 19 report (.pdf), the NTIA says an advisory committee due to meet Feb. 21 has likely found ways to make 1695-1710 MHz spectrum sharing viable for commercial firms and so "is confident that the FCC can proceed now with its process to repurpose" the spectrum.

A Jan. 22 final report (.pdf) of a Commerce Spectrum Management Advisory Committee working group recommends that spectrum sharing occur on the basis of "protection zones," which would require commercial carriers to demonstrate they could operate in the spectrum without causing interference to federal operations. The government utilizes the 1695-1710 MHz band to receive transmissions from the Polar Operational Environmental Satellite system and adjacent spectrum in the 1675-1695 MHz band for downlinks from the Geostationary Operational Environmental Satellite system.

The recommended approach contrasts with NTIA's earlier "exclusion zones" method, which would have prohibited commercial operations at a certain distance from earth receiving stations. The final report says new analysis of LTE cellular systems showed a significant reduction in the calculated distance at which an LTE system would potentially cause interference to satellite downlink operations, with separation distance being reduced in models by 21 to 89 percent.

The working group says its analysis is done under the assumption that commercial use in the 1695-1710 MHz band would be limited to mobile uplink only.

The working group also recommends that the government consider studying whether it could move earth receiving stations away from the top 100 markets, without taking a stance that it should do so. Government users told the group that there would be significant challenges associated with relocating receivers, such as ensuring that new, rural facilities have adequate backhaul.

The report also notes that the Polar Operational Environmental Satellite system is expected to reach the end of its lifespan by 2030, giving carriers greater potential access to the band over time.

For more:
- download the Feb. 19 NTIA report (.pdf)
- download the Jan. 22 CSMAC final report (.pdf)

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