Tuesday, December 4, 2012

Satellite Provider Petitions FCC for Additional 2.4 GHz Wi-Fi Channel and Exclusive Use

Globalstar, a U.S. company that operates low-Earth orbit (LEO) satellites providing voice and low-speed data communications, petitioned the FCC for approval for terrestrial use of their assigned Big LEO spectrum. Globalstar seeks to develop, market, sell, and deploy an terrestrial FDD LTE service by combing their Lower (1610-1618.725 MHz, uplink transmissions) and Upper (2483.5-2495 MHz, downlink transmissions) Big LEO spectrum. However, coexistence hurdles make terrestrial FDD LTE a long-term goal.

In the short-term, a Terrestrial Low Power Service (TLPS) in the Upper Big LEO spectrum is requested. And the promise is more efficient spectrum usage. Part of their spectrum holdings are directly adjacent to the 2.4 GHz ISM (Industrial, Scientific, and Medical) band in which Wi-Fi operates (they were granted this spectrum in 1995). The TLPS service would effectively enable use of Wi-Fi channel 14 in the U.S., which would increase aggregate Wi-Fi capacity since this channel does not overlap with existing Wi-Fi channels.

However, before you get too excited, realize that the use of this additional Wi-Fi channel would be exclusive to Globalstar.
Terrestrial Low-Power Service.  While the Commission and interested parties work through any technical issues described above, the Commission has an extraordinary opportunity to leverage Globalstar’s spectrum location in the 2.4 GHz band, the public’s prior investment in devices, and existing IEEE 802.11 technology to advance the rapid deployment of an innovative, pro-consumer TLPS.  Applying a unique, hybrid spectrum approach, Globalstar will provide this low-power broadband service over 22 megahertz of spectrum that includes both Globalstar’s exclusive terrestrial use spectrum at 2483.5-2495 MHz and adjacent unlicensed industrial, scientific and medical (“ISM”) spectrum at 2473-2483.5 MHz.  TLPS operations on this 2473-2495 MHz band segment are consistent with the 802.11 channelization scheme
This "hybrid" spectrum approach could have serious implications for spectrum policy in the U.S. The existing ISM band is an unlicensed band, open for use by anyone that meets certification criteria and testing. However, Globalstar effectively wants to retain exclusive use of their licensed spectrum (and rightly so) but couple it with unlicensed ISM spectrum to form this new service offering. The result would be the creation of a "licensed" Wi-Fi channel, that could only be developed and deployed by Globalstar.

The marketing used by Globalstar attempts to spin this approach as increasing the nation's broadband spectrum inventory, increasing capacity in congested metropolitan areas, and providing critical public-safety benefits during natural disasters.
If the Commission implements the necessary regulatory reforms to enable this hybrid approach, it will add 22 megahertz to the nation’s wireless broadband spectrum inventory.  In addition, this spectrum will be put quickly to use as American consumers utilize their current 802.11-enabled devices to receive Globalstar-managed TLPS, which will help alleviate the increasing congestion that is impeding use of existing 802.11 ISM channels in dense metropolitan areas... In addition, TLPS deployments will deliver meaningful public safety benefits.  During disasters such as Hurricane Sandy, still-operating 802.11-based hotspots can provide broadband and voice communications to citizens in affected areas who otherwise lack access to communications services.  The addition of TLPS facilities will augment this important post-disaster resource.
However, I fail to see how this hybrid spectrum policy will accomplish these goals. Since Globalstar will retain exclusive use of their licensed spectrum (2483.5-2495 MHz) no additional spectrum will be added to the nation's broadband spectrum inventory. Despite Globalstar's plans for 20,000 TLPS hotspots, they only currently have 550,000 worldwide subscribers and would likely need to partner with other Wi-Fi hotspot providers such as telecom carriers and wireline broadband providers (such as AT&T, Time Warner, Cablevision, and Comcast). Such business partnerships will prove difficult, as these existing providers will be reluctant to license and pay Globalstar for use of this additional spectrum. Finally, Globalstar's attempts to tie the TLPS service to public-safety are erroneous, since they are coupling the use of Wi-Fi hotspot access with their existing Mobile Satellite Service (MSS). Public safety has benefited from MSS service when terrestrial wireline operator facilities have been knocked out. The key here is the MSS backhaul facility, not the Wi-Fi access on the ground through the TLPS service. Similar public safety services are capable using existing Wi-Fi over unlicensed spectrum.

I'm not a spectrum policy expert. But my opinion is that Globalstar wants everything, but gives little in return. They want hybrid use of unlicensed spectrum coupled with their adjoining licensed spectrum holdings to create an exclusive-use Wi-Fi channel. This goes against the provisions established for the unlicensed spectrum and allows a single entity to profit from use of the spectrum and take advantage of the open nature and existing deployment base of the Wi-Fi eco-system. Moreover, this is simply a short-term plan until a long-term FDD LTE service can be deployed. Ultimately, no additional spectrum will be added for broadband use.

I can only see how this benefits Globalstar, harms unlicensed spectrum policy, and allows Globalstar to take advantage of the benefits of unlicensed spectrum by building an exclusive service on top of the Wi-Fi ecosystem.

I'm against it.



  1. Hi Andrew,

    Very interesting indeed.
    Please, could you explain how it would work?
    From some area covered by the Globalstar, a client would see a special BSA with some sort of SSID? I mean, it works like any other Wireless network with a wider covered area ?

    1. It would work just like normal Wi-Fi does. The difference is that the only APs that will be operating on Channel 14 would have to be operated by Globalstar. Nobody else would have authority to operate on that channel since it is partially licensed spectrum.

      The client devices would likely need to have their firmware / drivers updated for the US regulatory domain to allow them to look for APs on channel 14 since they don't today. I would expect, and this an assumption, that Wi-Fi clients would also be restricted to passively scanning for APs by listening to beacons; they wouldn't be allowed to actively scan with probe requests since it is licensed spectrum and they would interfere with satellite transmissions. This is similar to the restrictions placed on client scanning in the 5GHz DFS spectrum to avoid interference with military radar and TDWR radar at airports.


  2. A hybrid approach to the use of licensed plus unlicensed or 'licensed light' spectrum (3.65GHz, or White Spaces, etc.) is effectively what we have today by trial and error: Wi-Fi has become commonly used in mobile devices even though the two groups of technology, wide area mobile networks, and local area network combination of 3G, 4G and Wi-Fi b/g/n modes, were not 'designed' to work so closely together from the start.

    So, the question now is "Why don't fellow idiots at the FCC and within the various wireless groups set out to pursue the de facto reality of use of wireless as if they had a mind in it?"

    Think about how dumb the current situation really is: The marriage of unlicensed and licensed makes technical and practical sense. Users/small companies/groups are best situated to deploy 'small cells' including Wi-Fi. Studies confirm this but it does not take a rocket scientist to know it makes sense. Network operators are best at doing the heavy metal lifting and putting together systems that work reliably.. unlike what can happen using WiFi alone or an imagined extension to the ad-hoc nature of WiFi deployments and maintenance. On the other hand, mobile operators are near monopolists: given the grant to public spectrum and the appetite to increase profits, the huge industry is a bit likened to the BORG: "You will be assimilated, resistance is futile!"...

    Does Globalstar's proposal make sense? The devil is in the details in this and most other situations that I can think of that would be like this for co-use of spectrum. However, the WiFi and public interest groups should welcome it in concept... give it a fair hearing and encourage it if it can be brought to public benefit.

  3. The Globalstar proposal ignores Part 74 TV Broadcast Auxiliary Service (BAS) Channel A10 TV Pickup stations at 2,483.5-2,500 MHz. These stations are co-primary, not secondary, with S-band Mobile Satellite Service (MSS) Ancillary Terrestrial Component (ATC), and there is no sunset date to those grandfather rights. There is therefore broadcaster opposition, since A10 is still used for electronic news gathering (ENG) in many of the large metros. The FCC has assigned the Globalstar proposal a rulemaking number, RM-11685, and Globalstar has been quite active in its ex parte lobbying at the FCC.