Globalstar Wi-Fi Spectrum Plan Draws Fire

Doug Lung

Last month I wrote Globalstar Proposal Could Impact 2 GHz ENG Channels. Monday was the final day to file comments on Globalstar's Petition for Rulemaking to use part of its Mobile Satellite Service (MSS) spectrum at 2483.5 to 2500 MHz (BAS Channel A10) for “an innovative terrestrial low-power service (TLPS) offering.” Comments on RM-11685 appeared on the FCC's Electronic Comment Filing system from interests as varied as EIBASS (Engineers for the Integrity of Broadcast Auxiliary Services Spectrum) and AHAM (Association of Home Appliance Manufacturers).

The EIBASS comments addressed the issue I raised in my earlier article––Globalstar completely ignored grandfathered BAS licenses on Channel A10. In their comments, EIBASS co-chairs Richard Rudman (Remote Possibilities, San Paula, Calif.) and Dane Ericksen (consulting engineer at Hammett and Edison, San Francisco, Calif.) state: “The Globalstar Petition claims that it has 'exclusive terrestrial use' of 2,483.5–2,495 MHz. Globalstar is mistaken. There are indefinitely grandfathered, co-primary TV Broadcast Auxiliary Service (BAS) stations still operating on former TV BAS Channel A10 at 2,483.5 to 2,500 MHz. This inconvenient truth has been pointed out to Globalstar many times by the EIBASS and by the Society of Broadcast Engineers, Inc. (SBE). Yet the Globalstar Petition fails to mention the conflict with grandfathered TV BAS Channel A10 anywhere in its 82-page text.”

EIBASS concluded: “The allocations for MSS were done before cellular use exploded. It is now difficult to find areas where cellular coverage does not exist in some form. The approach of converting MSS to terrestrial-based cellular by adding a significant number of ATC/AWS-5/TLPS base stations stacks the deck in favor of MSS in at least two ways: It gives the MSS operator the economic advantage of building a terrestrial cellular network without having paid anything in spectrum auction fees, and creates a fundamental and serious interference potential to TV Channel A10 BAS operations. BAS use has skyrocketed in a manner not conceived by the Commission or incumbent users when those original allocations were made. EIBASS believes that should S-band MSS ATC/AWS-5/TLPS be allowed without first clearing the band of incumbent BAS users, the use of grandfathered A10 would have to effectively cease, making a mockery of the grandfather rights.”

AHAM's concern is that Globalstar should recognize that microwave ovens operate in this portion of spectrum. AHAM stated, “Before the Commission permits Globalstar to proceed, it must make clear that Globalstar has no greater rights than any other user of the unlicensed spectrum in the 2473-2495 MHz band and that it, and its customers, are obligated to accept interference from microwave ovens operating in that band.”

Clearwire was concerned about adjacent channel interference, asserting: “Although Globalstar does not provide adequate technical information, preliminary analysis suggests that the proposals will cause severe interference problems. For instance, Globalstar seeks authorization to provide service over a wide 22 MHz channel, using, in part, unlicensed spectrum for the WiFi-like TLPS proposal. Although wider channels can carry broadband traffic more efficiently, they also emit wider bands of signals into adjacent channels. An initial analysis of Globalstar’s TLPS proposal suggests that this wider channel would impair Clearwire’s adjacent channel operations.”

WISPA, the Wireless Internet Service Providers Association, is also concerned about adjacent channel interference, specifically interference into 2.4 GHz Wi-Fi Channel 11. Wi-Fi channels overlap, and as a result. only three channels (1, 6 and 11), can be used without interfering with each other. There is a three MHz guard band between these channels, but under Globalstar's proposal there would be no guard band between its proposed channel 14 TLPS service and channel 11.

WISPA stated: “The Commission therefore must seek comment on the potential for harmful interference that Globalstar's TLPS could potentially cause to Channel 11 and other channels within the 2.4 GHz unlicensed band.”

WISPA also noted that “Globalstar essentially seeks to privatize the 2473-2483.5 MHz portion of the unlicensed band. While it is true that, at the present time, broadband services do not operate in this spectrum, the Commission should consider whether Globalstar's proposed use of this portion of the unlicensed band is consistent with sound spectrum policy.” Concerned about the impact on Bluetooth and other unlicensed use of the spectrum, WISPA says, “The Commission must be assured, based on a thorough record, that the 'Globalstar-managed' network will not exclude or disrupt incumbent Part 15 uses.”

The Wi-Fi Alliance expressed concern about the potential loss of Channel 11 and the loss of the upper 2.4 GHz band for Bluetooth and future technologies, and is also concerned about giving this spectrum to one company: “The spectrum commons is supposed to be in place so that radio innovators can use the spectrum to its fullest extent, limited by the requirement not to cause interference to the licensees around it. By licensing some previously designated commons spectrum to a single firm, the FCC would diminish the spectrum available for future innovation in the commons. Any benefits to the use of 2473-2483.5 MHz accrue solely to Globalstar and not to the broader ecosystem of device manufacturers.”

It isn't surprising that the Bluetooth Special Interest Group (Bluetooth SIG) filed comments questioning the impact of Globalstar's proposal. The Bluetooth SIG notes: “Globalstar requests exclusive rights to 2473-2483.5 MHz and the interference into that band would appear to require Bluetooth devices to back off further as well as Wi-Fi devices that would have to cease the use of Channel 11. With the interference requirements it would in other words mean that additional congestion and further coexistence difficulties for Bluetooth since the traffic will need to be redeployed to the remainder of the band somehow. End user experience would suffer greatly.”

Iridium also opposed the Globalstar proposal, stating: “Iridium, as a Big LEO band MSS operator relied upon to provide lifesaving communications by first responders, the U.S. military, and the U.S. government, would be directly and adversely affected by Globalstar’s proposals that would impinge on the future availability of spectrum expressly allocated and authorized for MSS. Iridium is a fully operational and successful provider of the very types of MSS that the Commission envisioned in establishing the Big LEO MSS allocations and authorizations. In contrast to Globalstar, Iridium’s sole focus and purpose is to provide its critical satellite capabilities to the U.S. and the world.”

Even the U.S. GPS Industry Council weighed in with comments, expressing concern about terrestrial use of Globalstar's 1.6 GHz spectrum.

Considering the issues raised in these comments, I would not expect the FCC to move quickly on Globalstar's request--no one wants to see another debacle such as the LightSquared matter, especially if the media views this as an attempt by one company to take over Wi-Fi and Bluetooth spectrum.

Doug Lung

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.