The head of WiMAX operator Clearwire said its work is just beginning after the U.S. FCC's approval Tuesday of the company's joint venture with Sprint Nextel.

The FCC voted on Tuesday to allow Clearwire and Sprint to form New Clearwire, a service provider that will combine the frequencies held by both entities and eventually build a national mobile broadband network. The commissioners pushed aside objections by AT&T that the deal would hurt competition by putting too much spectrum in the hands of one entity. (Read a story about the week for the FCC.)

"To have the commission act as quickly as they did ... we're very gratified by that," said Benjamin Wolff, CEO of Clearwire, at the Wireless Communications Association International (WCAI) conference in San Jose. He was interviewed by WCAI President and CEO Fred Campbell.

But the two carriers still only have one commercially available mobile WiMAX network between them, in Baltimore, and the national infrastructure will have to be built from scratch in a harsh economic environment.

"The challenges are just beginning, to be candid," Wolff said. He cited the logistics of deploying as many as 37,000 cells, making sure technology from several infrastructure providers works together and working with device manufacturers to design products that are easy for consumers to use. Unlike cell phones, those will be sold by retailers, with no carrier subsidy.

"This is going up against all the traditional paradigms associated with the wireless business, so it is no small task," Wolff said.

But he said he wouldn't trade his own position with those of mobile giants Verizon Wireless and AT&T Mobility. The main reason is New Clearwire's spectrum holdings, which he said include more than 100MHz in many markets and more than 150MHz in some. That compares with chunks of only about 25MHz acquired by Verizon and AT&T in various markets through this year's auction of 700MHz frequencies, he said.

Wide swaths of radio frequencies make it possible to provide high speeds to more customers more economically, Wolff said. One element he didn't mention was that the 700MHz spectrum, which in the past has been used for TV, travels farther and penetrates walls better than the 2.5GHz frequencies New Clearwire holds.

The IDG News Service is a Network World affiliate.