LightSquared proposes to move its cell-type service away from GPS frequencies . . . and into a Weather Satellite Band.

The FCC has requested comment on a Petition for Rulemaking filed by LightSquared Subsidiary LLC seeking a new co-primary allocation permitting non-Federal terrestrial mobile use of the 1675-1680 MHz band.

You remember LightSquared – the company that wanted to deploy a tower-based wireless broadband network in the 1545-1555 MHz satellite downlink portion of the L Band, close to GPS frequencies. GPS users objected, and the National Telecommunications and Information Administration (NTIA) which administers federal spectrum, decided GPS interference concerns could not be overcome, whereupon the FCC pulled LightSquared’s tentative authorization.

With its recent Petition for Rulemaking (and other documents filed in late September), LightSquared seeks a work-around to its GPS headache (and possibly a Hail Mary to resurrect the company, which is now in bankruptcy).

LightSquared’s idea is to pair its existing and as-yet-uncontroversial authorizations for two 10 MHz uplink bands, at 1627.5-1637.5 MHz and 1646.7-1656.7, with a downlink (and terrestrial) channel at 1670-1680 MHz. This band is farther removed from GPS frequencies than LightSquared’s old request. The lower half of the band, at 1670-1675 MHz, is allocated for non-Federal fixed and mobile uses, and has been auctioned; LightSquared, through a subsidiary, has made arrangements to lease this segment. No problem there.

But the upper half of LightSquared’s proposed band, at 1675-1680 MHz, is not, at first glance, a good home for a high-powered cellular-type network. The primary allocation is for both Federal and non-Federal meteorological use, including downlinks for weather satellites. Remember those satellite videos showing the approach of Hurricane Sandy? Chances are they came through this band. Satellite downlink earth stations, which must receive extremely weak signals from satellites orbiting hundreds or thousands of miles away, are notoriously susceptible to interference. The 1675-1680 MHz segment is among the ultra-sensitive bands from which the FCC bars nearly all unlicensed devices

LightSquared is careful to state it would coordinate its operations with Federal users. But it does not say how. We suspect NTIA would not want a LightSquared tower within many miles of a Federal earth station receiving on the same frequencies. Yet the sine qua non of a mobile broadband network, such as LightSquared hopes to build, is ubiquity: customers want service anywhere they go. It remains to be seen how LightSquared can resolve these competing concerns. And missing from LightSquared’s petition is any offer to protect non-Federal users in the band. Actually, we’re not sure there are any; but if there are, the FCC is likely to conclude that they too are entitled to protection from LightSquared.

See the FCC’s public notice here. Comments are due on December 10, 2012, and reply comments on Boxing Day, December 26. If the FCC decides to proceed, it will solicit further comments by way of a Notice of Proposed Rulemaking. But we have a hunch NTIA may not let the matter get that far.