Google (NASDAQ: GOOG) and Qualcomm (NASDAQ:QCOM) might share a lot of visionary goals, like getting Internet access to far-flung places around the globe that don't yet have it, but when it comes to the 600 MHz guard bands and unlicensed operations, they're pretty far apart.
Both companies are among those submitting comments on the FCC's proposed rule changes for unlicensed operations in the television bands, repurposed 600 MHz band, 600 MHz guard bands and duplex gap and Channel 37. The FCC last year issued a Notice of Proposed Rulemaking (NPRM) on rules for unlicensed operations in the frequency bands that are now and will continue to be allocated and assigned to broadcast television services. The commission says it wants to allow for more robust service and efficient spectral use without increasing the risk of harmful interference to authorized users. The notice also addresses issues from the incentive auction due to happen next year.
It's the provision about "harmful interference to authorized users" that has Qualcomm saying "no way" to the commission's proceeding.
Qualcomm has said that from the outset of the 600 MHz incentive auction proceeding at the FCC, it has presented "numerous technical analysis" that show allowing unlicensed white space operations in the duplex gap and guard bands will cause harmful interference to licensed mobile operations in violation of the Spectrum Act and the FCC's rules. "This harmful interference will occur when a white space device is within 19 meters (or 62 feet) of a 600 MHz cellular device, using the FCC's proposed parameters," Qualcomm said in its filing. "Nothing has changed."
And don't even suggest that 7 meters, or 23 feet, is an acceptable protection radius. "We all know that 7 meters is not a viable, reasonable or defensible interference protection radius," Qualcomm said. "Devices using Wi-Fi and LTE are much closer than that all the time and virtually everywhere--at work, at home and in public places. So, the NPRM's own analysis and Qualcomm's extensive technical studies both confirm that the proposed rules for unlicensed devices in the duplex gap and guard bands are untenable," the company said.
In its comments, Broadcom pointed out that the NPRM asks whether the commission's proposed band plan for duplex gap operations and its proposed 40 mW power restriction on unlicensed devices would adequately protect LTE downlink. "We have conducted extensive research on this question. Our work, supported by both mathematical analysis and real-world testing, clearly indicates that the answer is 'yes,'" Broadcom said in its filing.
"Our analysis shows that unlicensed devices can easily coexist with licensees at powers well in excess of 40 mW, even when separated by 4 MHz rather than the 5 MHz separation contemplated in the NPRM for the duplex gap," Broadcom said. "In fact, our analysis shows that unlicensed devices can coexist with licensees at 3 MHz when operating at 40 mW. Our analysis therefore confirms that the commission can enable unlicensed operations in both the duplex gap and guard band at reasonable power levels."
Google analyzed both Broadcom's and Qualcomm's tests, and "Broadcom's analysis is vastly more realistic than Qualcomm's," Google said in its filing. "Google agrees that the touchstone of interference analysis should be how devices perform under reasonably foreseeable conditions," the company said. "The interference analyses submitted by Broadcom Corporation reflect this standard, while those submitted by Qualcomm do not."
However, it adds that even Broadcom's analysis relies on several "overly conservative" assumptions. "Under more reasonable assumptions… the commission's proposed 40 mW power limit is not only adequate to protect LTE, but greatly overprotective," Google said.
The FCC launched the proceeding last year and extended the comment and reply periods to Feb. 4 and Feb. 25, 2015, respectively.
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