Sprint-Nextel is reported to be seeking alternative funding for its Mobile WiMAX roll-out in the US and perhaps even considering a joint venture with fellow WiMAX proponent Clearwire.

Alternatively, the Wall Street Journal reported that the carrier might consider asking cable TV operators to invest in the project, presumably in return for distribution rights over the network.

Sprint is bound to build a wireless broadband network covering at least 40 million Americans by 2008 or lose its sizable 2.5GHz spectrum allocation.

After extensive testing of several different technologies, Sprint eventually chose 802.16e Mobile WiMAX, tapping Samsung and Motorola as infrastructure suppliers and Nokia for user devices. The company expects the project to cost some $3bn, but a group of shareholders has recently been putting pressure on management over the costs.

Clearwire, a fellow 2.5GHz WiMAX operator, was set up by Craig McCaw with funding from media interests and WiMAX Forum vendors.