LightSquared may change bands to save GPS

IDG News Service - Mobile broadband startup LightSquared proposed an alternative network plan on Monday in which it would use different frequencies to prevent interference with GPS.

LightSquared said Monday that it has proposed setting aside the part of its spectrum closest to the frequencies used by GPS (Global Positioning System) and instead using a band controlled by satellite carrier Inmarsat. The company recently reached an agreement with Inmarsat that allows it to use that spectrum. In its original plan, LightSquared would have moved into that band over two or three years as its business grew. Instead, it will use those frequencies from the beginning.

LightSquared plans to offer mobile broadband over both satellite and LTE (Long-Term Evolution), reaching remote areas of the U.S. while serving metropolitan areas with high-speed wireless. The U.S. Federal Communications Commission granted the company spectrum that lies near the GPS band on the condition that it work with GPS vendors, regulators and users to prevent interference between the services.

Reports by agencies involved in the testing showed that LightSquared's LTE transmitters would hinder or cut off GPS service for several types of receivers, including ones for public safety and aviation.

The FCC had set a deadline last Wednesday for that testing but granted LightSquared an extension until July 1.

After evaluating the data from the tests, LightSquared said it started developing an alternative spectrum plan to reduce interference. The plan, which was not laid out in detail in Monday's press release, involves the company temporarily leaving one band of 10MHz of spectrum for another 10MHz band that is lower in frequency.

The lower band is farther from the GPS frequencies and is largely free of interference problems except for an effect on "a limited number of high-precision GPS receivers," LightSquared said.

The higher band that it originally had planned to use in its launch will be set aside for testing and developing mitigation plans over the next few years, the company said.

LightSquared said the new plan will give it enough spectrum to serve its customers for the next several years and to roll out its services on schedule. The company has said it would launch commercial service later this year.

LightSquared plans to offer access to its network only through other mobile operators. Leap Wireless, operator of the Cricket mobile service, and retailer Best Buy plan to resell services on LightSquared's network.

Stephen Lawson covers mobile, storage and networking technologies for The IDG News Service. Follow Stephen on Twitter at @sdlawsonmedia. Stephen's e-mail address is stephen_lawson@idg.com