Don't count him out.

Craig McCaw may have largely dropped off the radar after his last move, the satellite-internet access provider Teledesic, crashed in 2002 in the face of crippling costs and meager demand. But now he's back and swinging for the fences. In yet another example of the standards battles that have long balkanized the cellular industry, the telecommunications entrepreneur is taking sides, staking his next effort on WiMax, which some expect to be the successor to WiFi.

He's looking at a tough battle ahead. He just engineered a major deal with Sprint Nextel to combine its WiMax investment with his Clearwire venture to roll out high-speed wireless internet access. But Clearwire faces stiff competition from a rival "4G" networking technology known as Long-Term Evolution, or L.T.E, which is being championed by Sprint Nextel's competitors, AT&T and Verizon Wireless.

It may also have to go on the defensive against whatever Verizon Wireless chooses to do with the large swath of wireless spectrum in the powerful 700-MHz band that it paid $9.4 billion for in the F.C.C.'s auction in March (under the auction rules, Verizon is now required to build out a network with the spectrum that is open to devices and applications from all providers).

But McCaw cuts an inimitable profile. He is inarguably one of the three or four figures most responsible for the remarkable growth of the mobile and wireless industry in the last two decades. The son of a TV and radio tycoon, he built his father's small regional company into a major cable provider and later created McCaw Cellular, which he sold to AT&T in 1994 for $11.5 billion. Two years later, he effectively took over struggling wireless carrier Nextel, helping to build it into a nationwide company that merged with Sprint in 2005; McCaw personally pocketed about $8.3 billion in the deal.

However, his XO Communications declared bankruptcy in 2002, and that same year McCaw shut down Teledesic, an ambitious effort to provide internet access via satellite. (McCaw says now that Teledesic "may have been a little bit before its time.")

McCaw started Clearwire the following year. In hindsight, McCaw's strategy has always been the same—namely, to use the latest technology to provide the fastest communications network to as many people as possible.

"This is his third time around at this business," says Benjamin Wolff, McCaw's longtime lieutenant and Clearwire's C.E.O., referring to McCaw's earlier successes with McCaw Cellular and Nextel. "His ability to see things from the visionary perspective is unmatched in the industry."

WiMax is without a doubt an alluring technology. With its potential to offer broadband connections over long distances using licensed spectrum, it has generated tremendous hype in the last two years. At the time of its merger announcement with Sprint Nextel, Clearwire also said that an alliance of major technology players, including Intel, Google, Motorola, Time Warner Cable, and Comcast, were investing a total of $3.2 billion in the venture. And WiMax is thought by many to have a two- to three-year head start on systems built on L.T.E.