Stymied in their attempts to establish viable cellular products thus far, Comcast, Time Warner Cable (TWC) and the increasingly ambitious Bright House Networks are exploring involvement with the WiMAX networks being built by Clearwire and Sprint Nextel.

The three MSOs are reported by The Wall Street Journal to be considering investing in a new wireless broadband company that would be operated by Sprint and Clearwire.

Sprint and Clearwire are building separate but compatible WiMAX networks, which together would cover most of the U.S. The two want to raise at least $3 billion for a joint venture (JV).

Comcast is considering putting in as much as $1 billion toward that figure, and TWC might put in as much as $500 million. Bright House might contribute between $100 million and $200 million, the WSJ reported.

The cable companies would get equity in the business and would be able to purchase wholesale access to the network to offer their own high-speed wireless data and voice services to customers.

While adding simple mobile telephony to the bundle would be advantageous, cable engineers have been talking for some time about the possibility of using dual-mode handsets that would work with wireless networks when roaming and with traditional broadband networks while in the home or office. Google has been talking about the same thing, inspiring speculation that Google might also be interested in getting involved in the cable-WiMAX venture the WSJ reported on.

Two years ago, six of the largest cable companies entered into a JV with Sprint that ended up with some of them offering mobile phone service under the Pivot brand name, but the collaboration soured and Sprint will not expand the reach of Pivot.

A consortium of cable operators – including Comcast, TWC, Bright House and Cox Communications – purchased $2 billion worth of wireless spectrum in a 2006 government auction, but they have yet to use it.

In the Federal Communications Commission’s (FCC) 700 MHz auction that just concluded (story here), Cox spent more than $300 million for spectrum licenses. That might give Cox the capability to develop its own wireless broadband networks in some of its largest markets.

Bresnan Communications and Vulcan Spectrum (run by Charter Communications Chairman Paul Allen) also won 700 MHz licenses. Neither has announced plans for those licenses.

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