Sprint Nextel and wireless broadband provider Clearwire have unveiled a new $12 billion partnership that will combine their planned nationwide mobile WiMAX networks. Of course, the two companies signed an agreement to share WiMAX infrastructure last year then abandoned the effort a few months later when the costs became blindingly apparent.

The new deal, however, brings in new partners including cable operators Comcast, Time Warner Cable and Bright House Networks, chip manufacturer Intel and search engine giant Google, according to reports. These five firms plan to invest $3.2 billion between them, reducing the financial impact on Sprint and Clearwire. The deal also involves a series of commercial agreements with the strategic investors, including 3G and 4G wholesale agreements.

The joint venturem which will operate under the Clearwire name, will be 51%-owned by Sprint assuming a per-share price of $20. Sprint and Clearwire own the bulk of WiMAX-capable 2.3GHz and 2.5GHz spectrum in the US.