Proposed US wholesale LTE network LightSquared will be blocked by the Federal Communications Commission (FCC) following recommendations from the National Telecommunications and Information Administration (NTIA).

The NTIA has carried out an independent evaluation of tests (conducted by federal agencies) which concluded that LightSquared’s network, which operates on spectrum close to that used by GPS technology, interferes with critical GPS services.

“We conclude that LightSquared’s proposed mobile broadband network will impact GPS services and that there is no practical way to mitigate the potential interference at this time,” said NTIA administrator and assistant secretary for communications and information at the Department of Commerce, Lawrence E. Stricking, in a letter to FCC chairman Julius Genachowski.

An FCC spokeswoman said in an emailed statement to Bloomberg that the FCC is now preparing to withdraw the preliminary approval it granted LightSquared last year as a result of the recommendations. "The commission clearly stated from the outset that harmful interference to GPS would not be permitted. The commission will not lift the prohibition on LightSquared," the spokeswoman said.

The FCC stance is a huge setback for LightSquared which has long been hindered by opposition from GPS companies and the results of government tests suggesting the proposed network interferes with GPS devices. It is attempting to build a national 4G LTE wireless network that would provide mobile broadband services to wholesale customers.

LightSquared remains adamant that the conclusions of recent tests by the Space-Based Positioning, Navigation and Timing national executive committee (PNT ExCOM) (claiming that its network interferes with GPS receivers) should be re-evaluated. LightSquared has previously questioned the validity of the test results, saying they were “rigged” by GPS device manufacturers and government end users to produce “bogus results.”

In its latest statement yesterday, the company said it disagrees with the NTIA and PNT ExCOM recommendations as they rely on “interference standards that have never been used in this context, and were forced by the GPS community in order to reach the conclusions presented today.”

The statement added that LightSquared is committed to resolving the concerns and is confident the parties will "continue the on-going efforts to explore all engineering options and alternatives to find a solution to this difficult issue," and said it "fully expects” the FCC to recognise its “legal rights to build its US$14 billion, privately financed network."

Throughout the debate, US operator Sprint has twice extended its deadline for LightSquared to win regulatory approval. Clearance by the FCC is a condition of a 15-year spectrum and equipment sharing deal between the two companies.