Under the proposed plan, the companies expect that Open Range would lease L-band satellite spectrum from LightSquared and resell the company's satellite-based mobile service, once it's launched. In addition, the companies would work together to build out Open Range's network and would have a reciprocal roaming agreement between their respective networks. The companies said they have reached an agreement in principle and expect to complete a definitive agreement soon.

The announcement, which the carriers said represented a major step toward fulfilling the National Broadband Plan of the U.S. Federal Communications Commission (FCC), came a day after opponents of LightSquared's network plans formed the Coalition to Save Our GPS. The group charges that evidence shows LightSquared's network would interfere with GPS (Global Positioning System) because it would operate in the same frequency band at greater power.

The FCC approved LightSquared's network plan partly on the basis that it would use satellites to bring Internet access to 100 percent of the U.S. LightSquared and plans to build an LTE (Long-Term Evolution) network, selling one or both types of services wholesale to other carriers rather than operating a retail business of its own.

The Open Range agreement is the first deal with a retail partner that LightSquared has disclosed. The arrangement still needs to be reviewed by the U.S. Department of Agriculture's Rural Development Utilities Program, and the spectrum leases would have to be approved by the FCC.

Open Range, which has already built a WiMax-based, branded broadband service for underserved rural markets, should be able to help LightSquared reach those areas. The companies characterized their agreement as a move that would help bring fast Internet access to consumers, businesses, tribal organizations, public safety and other users.