CTIA Urges Caution on H-Block Auction Rules
Wireless carriers told the FCC that if it proceeds with an auction of H and J block PCS spectrum, proper controls must be in place to protect other spectrum incumbents. Carriers spelled out the levels of controls they believe are necessary in filings at the FCC in response to a proposed rulemaking on auction service rules.
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CTIA said the level of protections proposed by the Commission are significantly lower than the levels needed to prevent interference. In the rulemaking the FCC suggested some numbers for out-of-band emission limits and power levels, 2 variables controlling interference.
On power levels, for example, the FCC said power levels as high as 23 dBm at one meter may be possible without harming other PCS users. CTIA said its testing suggests limits of 5 dBm for transmissions in the upper third of the 1915-1920 MHz band and a power limit of 8 dBm for transmissions in the middle third of the band are needed to protect against intermodulation and overload, 2 critical forms of interference.
“The testing was done over several weeks and it was very complex,” a carrier source said. “What the testing consistently showed was that the FCC was at the least a little over-optimistic as to what the power levels should be and what the out-of-band emissions should be.”
“CTIA notes that millions of wireless subscribers rely on PCS handsets that were designed when the 1915-1920 MHz band was designated for unlicensed use and posed no practical risk of interference,” the association said. CTIA said that under proposed power limits, in areas where signals are weak but still acceptable, the new interference could mean “additional lost calls, distorted audio, inability to make and/or receive calls, inability to determine location (E-911), and lower data rates.”
Verizon and Sprint filed joint comments that largely followed CTIA’s arguments. “While we generally favor spectrum assignments that promote advanced, flexibly licensed services, the Commission must ensure that in making such assignments, it does not cause interference to licensed services in adjacent bands. With respect to the H Block in particular, the Commission must ensure that the technical requirements applied to it are sufficient to prevent interference to operations in the nearby PCS spectrum blocks.”
Nextel reiterated its general support for opening the H block for auction. Nextel disagreed about the need for tight controls. “Protecting the existing PCS bands requires no special technical constraints on H Block,” Nextel said: “The concerns raised by some in the PCS industry are contrary to longstanding industry practices, a rigorous probability analysis, and independent lab measurements.”
T-Mobile took a middle course, arguing that while more spectrum for advanced wireless services is critical, it must be accompanied by protections. “To ensure that these interference concerns do not become a reality, T- Mobile believes the Commission must establish service and technical rules for the H and J blocks that will adequately protect incumbent PCS licensees in the A-F blocks and Mobile Satellite Service (MSS) incumbents in the 2000-2020 MHz band.”