Clearwire has run into some money troubles. In a third-quarter earnings report, the company said it has "not yet secured future funding," and must implement a number of cost-saving measures, including layoffs and a suspension of additional market roll outs.

"We continue to pursue all options for future funding including debt, equity or a potential sale of excess spectrum or other assets, and we remain cautiously optimistic that we will resolve our short-term funding needs in the near future," Clearwire said.

Clearwire will suspend the launch of its Clear services in Denver and Miami, and will not pursue Clear-branded smartphones, the company said. Clearwire will also lay off about 15 percent of its employees, implement a "substantial reduction" in its number of contractors, and reduce sales and marketing spending.

Clearwire will also suspend zoning and permitting in sites where it had planned to roll out until it can secure more cash. This will potentially save the company between $100 million and $200 million this year and in the first half of 2011.

The news comes two weeks after Clearwire announced plans to launch its 4G services in New York City, San Francisco, and Los Angeles later this year. In August, it unveiled Rover, a pay-as-you-go mobile broadband service aimed at tech-savvy "digitally addicted" customers.

To solve its money woes, Clearwire is considering a number of options, including strategic transactions, additional debt or equity financings, or asset sales. Clearwire investors include Intel, Comcast, Sprint, Google, Time Warner Cable, and Bright House Networks.

In a statement, Sprint reiterated what chief executive Dan Hesse said recently. "Sprint has been in discussions with Clearwire regarding the financial status of its ongoing operations as well as Sprint potentially providing new financing," the company said. "We expect those discussions to continue as we review alternatives with Clearwire. There is no assurance that the discussions will result in any transaction with Clearwire."

Sprint's own 4G plans remain unchanged, the company said.

By the end of the quarter, Clearwire had 2.84 million subscribers, of which 1.01 million were retail subscribers and 1.83 million were wholesale subscribers. Clearwire added 150,000 retail customers during the quarter. The company expects to hit 4 million subscribers by year's end.

Clearwire reported revenue of $147 million for the third quarter.