Google worries about warehousing in 3.5 GHz band

Google has a lot of concerns about CTIA's recommendations for spectrum sharing in the 3.5 GHz band, one of which is that they raise the potential for spectrum warehousing.

In a recent filing with the FCC, Google said CTIA's overall recommendations "threaten to fragment the management" of shared 3.55 GHz spectrum in a way that both reduces the protection of incumbent systems and limits the opportunities for sharing unused priority-access (PA) spectrum.

Under the FCC's Further Notice of Proposed Rulemaking (FNPRM) released in April 2014, the commission is looking at applying spectrum sharing to 3550-3650 MHz spectrum and is considering extending the service to 3700 MHz, providing a total of 150 MHz of spectrum for Citizens Broadband Radio Service (CBRS).

The FCC's three-tiered access and sharing model would be composed of federal and nonfederal incumbents, priority access licensees (PALs) and general authorized access (GAA) users. GAA users basically would be unlicensed users, like Wi-Fi users today, while PALs, such as mobile operators, would most likely use the spectrum for multiple applications, including mobile broadband and small-cell operations.

Part of the proposal calls for having a centralized spectrum manager, or Spectrum Access System (SAS), assign channels dynamically.

"In particular, CTIA appears to be suggesting that (1) devices may rely on spectrum sensing alone, rather than SAS management, and (2) service providers should not be required to exchange information about the usage of Citizens Band Radio Service (CBRS) devices on their networks," Google wrote in its filing.

"CTIA's recommendations also raise concerns about warehousing of spectrum," Google wrote. "In this proceeding, the commission seeks to 'drive greater productivity and efficiency in spectrum use' through spectrum sharing technologies. As a result, the commission has expressed a clear preference for promoting intensive shared use and has proposed both technology and policy levers to 'discourag[e] [spectrum] warehousing.'"

The web-search giant points out that if information regarding actual use by PA licensees could be withheld from the SASs, entities could easily prevent other operators from using the shared resource by reserving PA spectrum, failing to use it, and failing to disclose their nonuse.

Wireless-industry players started picking apart the FCC's plan for the 3.5 GHz band last year. The WiMAX Forum urged the commission to not include 3.65-3.7 GHz spectrum in its CBRS regulatory plan, at least not until the FCC's spectrum-sharing techniques could be successfully employed over a few years.

Last year, Verizon (NYSE: VZ), chipmaker Qualcomm (NASDAQ:QCOM) and infrastructure vendor Ericsson (NASDAQ: ERIC) collaborated on field trials of spectrum-sharing technology in the 3550-3650 MHz band at multiple locations. The trials were designed to help Verizon understand the propagation characteristics of 3.5 GHz spectrum in a real-world environment.

For more:
- see this Google FCC filing

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