U.S. regulators are seeking public comments on LightSquared’s December petition for a ruling that commercial GPS receivers are not entitled to protection from interference caused by a broadband wireless network operating within technical parameters set by the government.

The Federal Communications Commission’s (FCC) request for comments is the latest step in the battle between the GPS industry and LightSquared over the company’s plans to use frequencies reserved for satellite services to launch a terrestrial broadband network.

Comments are due by Feb. 27, and responses by March 13. LightSquared has welcomed the FCC’s move, which comes as a lifeline for the private equity-backed company, already disputing tests that show its transmissions will interfere with a wide range of GPS receivers.

GPS makers and users argue that LightSquared’s proposal fundamentally changes the use of a frequency spectrum that has long been set aside for low-power satellite signals. The FCC has made deployment of LightSquared’s network contingent on resolving GPS interference.

Proponents for the GPS industry argue that the FCC should block LightSquared’s plans, or make the company pay the cost of protecting millions of GPS receivers from the interference. LightSquared claims the interference is a result of poor GPS receiver design, and industry should pay.

Testing for the FCC shows LightSquared’s transmissions do interfere with GPS receivers, but not because signals are leaking in the adjacent band. Instead receivers are looking into the neighboring band and being overpowered by LightSquared’s transmissions.

LightSquared argues this is poor design, and as a result, commercial GPS manufacturers are not entitled to legal protection from interference. But congressional directives will still require the interference issue to be resolved, industry points out.