Clearwire on Monday announced the completion of its wireless broadband business and network merger with Sprint Nextel and sketched out its competitive positioning among its cellular rivals.

The Kirkland, Washington-based company’s plans, which were drawn up well before the economy skidded into recession, could face jarring realities that affect its investors’ ability to effectively push Clearwire’s services.

One-time rivals Sprint and Clearwire have now officially merged their U.S. wireless broadband operations, which were based on WiMAX, the still-emerging mobile data communications standard.

Sprint Nextel, which now owns 51 percent of Clearwire, will continue to operate its cellular network independently of Clearwire. But the two companies plan to package and sell each other’s services and allow for mutual roaming arrangements.

Clearwire said it will use an additional $3.2 billion investment it got from Comcast, Time Warner Cable, Bright House Networks, Intel, and Google, to unveil its nationwide U.S. network. (Tech Consortium Bids $14.5B on WiMAX)

Like Sprint, the cable operators will sell Clearwire’s wireless services as the sought-after wireless addition to their triple-play packages of phone, Internet, and TV services. (Will Google and Cable Firms Rejuvenate WiMAX?)

Clearwire’s WiMAX wireless service, which competes with both fixed “home-based” services such as DSL and cable modems and mobile data services, will be branded “Clear.”

In its mobile business, Clearwire will face off against rivals AT&T and Verizon Wireless, which are targeting growing demand for mobile access to Internet services.

“We are the underdog facing much larger companies, but we have an open Internet business model that isn’t encumbered by fears of cannibalizing existing wireless or wireline revenues,” Clearwire CEO Ben Wolff said at a press conference.

But Clearwire’s competitive landscape is a bit confusing. It will both partner with and compete against cable operators.

It will compete with three of the four major wireless carriers–AT&T, Verizon Wireless, and T-Mobile–because the No. 3 carrier, Sprint, is its largest shareholder.

But the economy will be Clearwire’s biggest wild card, said analyst Tim Farrar, president of Telecom Media and Finance Associates.

“As the economy gets worse you will see the mobile carriers offer increasingly attractive data plans which will force Clearwire into its comfort zone, which is selling its services as an alternative to DSL and cable modems,” he said.

Clearwire operates in 50 U.S. markets and has sold its WiMAX services almost exclusively as a rival to DSL and cable modems.

It is the third broadband “pipe” to the home and offers subscribers competitive pricing and the additional benefit of portability.

Unlike DSL and cable modem subscribers, WiMAX subscribers are not home-bound. They can take their PCs to the local coffee shop or across town and work from there.

But competing with AT&T, Verizon Wireless, and T-Mobile as a high-value nationwide mobile service will require Clearwire to quickly build a very expensive network.

Ultimately all that would buy them is entrance into an ultra-competitive market, where Clearwire’s advantages are not quite as evident, Mr. Farrar said.

In the meantime, the economy could force Sprint and the cable operators who have invested in Clearwire to focus their critical marketing resources on much more immediate goals, he said.