Advertisement
News
Advertisement

LightSquared blames GPS industry for interference mess

Thu, 06/30/2011 - 8:05am
Maisie Ramsay, Wireless Week

LightSquared issued a 318-page report to the FCC today reporting that its network could have a catastrophic effect on GPS service if allowed to go live in its original spectrum bands.

In a subsequent document listing possible remedies for the problem, LightSquared placed the blame squarely on the GPS industry, saying manufacturers of GPS receivers had purposely designed them to eavesdrop on neighboring spectrum bands.

"It is inescapable that it is their [the GPS industry] disregard for the Commission's policies regarding the immunity of receivers to transmissions in nearby frequency bands that is the source of the technical problem," LightSquared wrote.

LightSquared also accused those in the GPS industry of trying to hide their culpability with a "campaign of distortion and obfuscation."

Tests have confirmed that LightSquared's signal does not bleed into neighboring spectrum bands, but sensitive GPS receivers are nonetheless affected by the high-powered transmissions. Representatives of the GPS industry have repeatedly denied that receiver designs are to blame for the interference problem.

LightSquared's filing states that the interference to GPS receivers comes not from improper transmissions from its base stations, but "because legacy GPS receivers do not adequately reject transmissions from base stations operating in the adjacent frequency band because the GPS receivers have been deliberately or, sometimes, inadvertently, designed or manufactured with the assumption that there would be no adjacent-band terrestrial transmissions – ignoring regulations first adopted in 2003 that permit such transmissions."

Stakeholders in the GPS industry say the FCC should not have granted LightSquared a waiver to build a high-powered LTE network in spectrum adjacent to GPS bands without first testing for interference, and they want LightSquared to move away from the MSS band.

"LightSquared's proposed operations defy the law of physics, and therefore simply will not work. The report findings are starkly clear: The only real solution to the LightSquared interference problem is to move out of the MSS band altogether," the Coalition to Save Our GPS stated in response to LightSquared's report to the FCC.

The scale of the interference problems prompted LightSquared to scrap its plans to deploy a land-based LTE network in its own spectrum. Instead, the company wants to move the service to 10 MHz of Inmarsat's spectrum located farther away from GPS bands.

Today's report did not contain tests of this alternate scenario, which LightSquared claims will resolve the interference problem for more than 99 percent of receivers. Government officials want the FCC to mandate further tests conducted on LightSquared's new plan before allowing the company to launch its network.

The FCC said in its conditional waiver issued to LightSquared in January that the company could only move ahead with its plan for a hybrid satellite-terrestrial LTE network if it could prove that the service wouldn't harm GPS.

The FCC could block LightSquared if the company can't prove its revised plan solves the interference issue. It is not clear whether the FCC will consider the GPS industry's culpability in its final decision.

Advertisement

Share This Story

X
You may login with either your assigned username or your e-mail address.
The password field is case sensitive.
Loading