An FCC-created working group has concluded that LightSquared operations would result in “potentially significant” interference to GPS; LightSquared has responded with some ideas of its own.

Several months ago we reported on an unusual FCC waiver. The recipient, a company called LightSquared, holds the license to a chunk of spectrum allotted for the Mobile Satellite Service (MSS), a service that, contrary to its name, never really got either moving or off the ground. It was supposed to provide nationwide telephone service delivered by satellite. Perhaps a good idea when first conceived, MSS was ultimately surpassed by the speedy expansion and falling prices of terrestrial wireless phone service.

The LightSquared waiver appeared to pave the way for LightSquared to market its system more as a ground-based system with some satellite capability, rather than as a satellite service with limited “ancillary” terrestrial operation. That alone was surprising, particularly in view of the facts that (a) LightSquared hadn’t even asked for a waiver in the first place and (b) the Commission hustled its approval through in just a couple of months. (Non-routine waivers like this one typically take at least a year or two to process.)

In granting the waiver, the Commission acknowledged a potential problem posed by the proximity of (a) LightSquared’s spectrum and (b) spectrum used for Global Positioning System (GPS) operations, with the consequent risk that LightSquared could interfere with GPS. That would disrupt not only the gadgets in our cars, but also more consequential systems like those used for landing airplanes safely. To scope out just how big the problem might be, the Commission created a technical working group to run some tests. The group – composed of representatives of LightSquared and GPS-related industries – was charged with:

analyzing a variety of types of GPS devices for their susceptibility to overload interference from LightSquared’s terrestrial network of base stations, identifying near-term technical and operational measures that can be implemented to reduce the risk of overload interference to GPS devices, and providing recommendations on steps that can be taken going forward to permit broadband wireless services to be provided in the LBand MSS frequencies and coexist with GPS devices

LightSquared’s participation in the working group was not entirely voluntary: as a condition of its waiver, LightSquared was required to “help organize and fully participate” in the group.

The working group submitted its report to the Commission a couple of weeks ago. The Commission, in turn, has now requested public comment on the report’s findings and on some “recommendations” advanced by LightSquared in response to those findings.

The report is lengthy – 318 pages, not including another 600+ pages of appendices (you can find links to all of them through the FCC’s ECFS on-line docketing system here) – and highly technical. The bottom line is that the working group’s tests demonstrated “potentially significant interference” between LightSquared operations in the upper 10 MHz portion of its band and “various GPS receivers”. “Some interference issues” were also identified in the lower 10 MHz portion of the band.

In its recommendations LightSquared lambastes GPS device manufacturers generally. But presumably recognizing that threatening the operation of gazillions of vitally important GPS units is probably not the best way to curry favor with the government or the public, LightSquared “expresses a willingness” to:

  1. operate at lower power than permitted by its existing FCC authorization;
  2. agree to a “standstill” in the terrestrial use of its upper 10 MHz frequencies immediately adjacent to the GPS band; and
  3. commence terrestrial commercial operations only on the lower 10 MHz portion of its spectrum and to coordinate and share the cost of underwriting a workable solution for the small number of legacy precision measurement devices that may be at risk.

The FCC is looking for feedback on those proposals, and on the working group’s report as a whole. Historically the FCC has been very protective of the GPS band. It also gives great weight to the views of the federal government, which operates the GPS system and makes heavy use of it for defense, navigation, law enforcement, etc. Federal GPS users in the past have vigorously and successfully resisted incursions into the band from private interests, and will no doubt play a major part in the deliberations here.

Comments are due by July 30, 2011; reply comments by August 15, 2011. In view of the length and highly technical nature of the report – not to mention the size of the universe of potentially interested commenters (think everybody with a GPS unit, everybody who flies in airplanes, etc.), those deadlines seem a bit short. Be forewarned.