Cable group disputes Globalstar's arguments against freeing 5.1 GHz band for Wi-Fi

Efforts to open up the 5.1 GHz band for use by high-power, outdoor Wi-Fi equipment has garnered widespread support, but faces staunch opposition from one company using the band: mobile satellite service (MSS) operator Globalstar. However, the cable industry contends that new research from CableLabs and experts at the University of Colorado refutes arguments Globalstar has made to keep the frequencies from being opened up.

The research was submitted yesterday to the FCC by the National Cable and Telecommunications Association (NCTA), which called for swift action to free up the 5150-5250 MHz portion of the Unlicensed National Information Infrastructure (U-NII)  band to enable its use for higher power (up to one watt) and outdoor Wi-Fi transmissions. Unlicensed operations in the band are currently restricted to lower wattage and indoor operations.

The proposed relaxation of regulations for the 5.1 GHz band are part a broader FCC move to release more 5 GHz frequencies for gigabit Wi-Fi use.

"The 5 GHz band is the country's single best, and perhaps only, opportunity to rapidly bring additional Wi-Fi channels into use and to thereby address consumer demand and empower Gigabit Wi-Fi. And the U-NII-1 portion of this band--100 MHz of spectrum perfectly suited to Wi-Fi--is the country's best chance for additional 5 GHz access in the near term," said NCTA Senior Vice President Rick Chessen in a letter to Julius Knapp, chief of the FCC's Office of Engineering and Technology.

Globalstar currently uses the spectrum for four licensed MSS feeder links that serve some 85,000 customers globally. Globalstar contends that sharing the 5.1 GHz band with high-wattage, outdoor Wi-Fi would impact the company's operations, and, in turn, diminish its "satellite power availability, user capacity, and geographic service availability."

Researchers from CableLabs and the University of Colorado first tried to refute Globalstar's interference argument via a study submitted in July 2013. At the time, the researchers argued that Globalstar's technical argument was unreliable because it was based on a set of invalid assumptions and inputs. In response, Globalstar filed a second technical paper prepared on its behalf by Roberson and Associates on Nov. 29, 2013, which again backed claims of potential interference.

CableLabs and the University of Colorado conducted a second analysis of U-NII-1sharing, which again purports to show that shared Wi-Fi use in the Un-NII-1 band will not cause harmful interference. The new study uses a dynamic simulation that analyzes the interactions of every individual Globalstar satellite with Wi-Fi access points.

According to NCTA, because U-NII-1 is already designated for unlicensed use, service providers could bring it online very quickly through modest changes to existing equipment. Further, the group said much of the existing consumer equipment ecosystem already contains U-NII-1-enabled Wi-Fi chips.

Meanwhile, multiple parties have filed objections to the FCC's separate NPRM that would allow Globalstar to operate a terrestrial low power service (TLPS) over its 11.5 MHz of previously licensed S-band spectrum at 2483.5-2495 MHz, as well as the adjacent 10.5 MHz of unlicensed spectrum at 2473-2483.5 MHz

Critics of the NPRM--issued in November 2013--expressed a number of concerns, including fears that Globalstar's TLPS would interfere with 2.4 GHz Wi-Fi channel 11 and other channels within the 2.4 GHz unlicensed band, including those used for Bluetooth. Some commenters also disapproved of the idea that the FCC might create spectrum rules to benefit a single service provider.

For more:
- see this NCTA filing
- see this TVTechnology article

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