Sprint plans to raise $2 billion in new debt funding today that it said could be used to defray the cost of upgrading its network, pay off its debt or pour additional cash into Clearwire.

The wireless operator is overhauling its network, a project that proved more expensive than originally planned after Sprint accelerated its schedule for the build-out.

It has also had to pour hundreds of millions into Clearwire to keep the company afloat after it threatened to default on a debt payment. Sprint is Clearwire's largest investor.

The latest appeal to capital markets came just three months after Sprint raised $4 billion in debt to help pay for its network modernization project and Clearwire financing.

The company said last year it would need to raise up to $7 billion to pay for its network upgrades, iPhone subsidies and debt payments, while still maintaining its $2 billion cash balance. Sprint is paying Apple a minimum of $15.5 billion for the iPhone over the next four years.

The new funding round was announced just days after Sprint reportedly canned a proposal to pay up to $8 billion for prepaid provider MetroPCS.

Sprint's board of directors made an 11th-hour decision to back away from the deal last week, according to unnamed sources cited by The Wall Street Journal.

Sprint and MetroPCS declined to comment on the rumor.

Takeover rumors about MetroPCS have often been linked to no-contract rival Leap Wireless International, but AT&T has also recently been said to be interested in MetroPCS as it looks for more sources of spectrum in the wake of its failed acquisition of T-Mobile USA.