Based as it is on licensed spectrum, Mobile WiMAX is bittersweet. Vendors know operators have spectrum to use equipment they’re developing, but licensed spectrum closes the door on those who don’t have it.

The U.S. Federal Communications Commission could change that when it auctions some of the last available 700-MHz spectrum broadcasters will abandon next January. Besides adding billions of dollars to government coffers, the auction could provide new spectrum for mobile WiMAX.

“I’m told by my technical teams how sweet that spectrum is in terms of the propagation characteristics and the opportunity to do WiMAX there,” says Regina Moldovan, senior manager of WiMAX marketing at Nortel. “There’s definitely an opportunity.”

Although WiMAX Forum mobility specifications take 700 MHz into consideration, certifications in that strata are not a top priority, says Julie Coppernoll, director of WiMAX marketing at Intel. “I think most people would say, ‘Let’s get WiMAX rolled out on 2.5 [GHz] first and then look at other spectrums and frequencies later,’” she says. “There’s 2.5 and 2.3 in Korea, and in Europe and other parts of the world they are already rolling 3.5. I’d say they have their plates full in the short term.”

Coppernoll speculates there may be a chance operators will be interested in the 700-MHz band for mobile WiMAX next year and that Intel, as well other silicon players, would be able to respond “fairly quickly” if that happened. Another uncertainty surrounding the 700-MHz frequency band is that no one is sure who will own the spectrum. It could be the cable industry, which has formed a group called SpectrumCo that has already purchased wireless spectrum at 1.7 GHz and 2.1 GHz. But nobody—probably not even the cable companies themselves—knows how that’s going to be used.

Non-carrier types, including public safety agencies in the U.S., also want a chunk of that 700-MHz spectrum as a good foundation on which to build a national first responder network.

However, 700 MHz comes with technological baggage: “We’ve done a lot of work on the 700-MHz band…and there are guardband issues, so how much of that spectrum is usable is something that you need to understand,” says Mark Slater, vice president of Nokia Siemens Networks. “In reality it’s a longer term play.”

The lower frequency range, however, does have its attractions. “It has much better performance characteristics [than 2.5 GHz],” says Arthur Giftakis, Vice President of Engineering and Operations of TowerStream, a nationwide fixed/portable WiMAX provider in the U.S. “At 700 you’re doing more than one wall penetration; in fact, you’re doing two wall penetrations in the urban areas. It also goes farther. We’re a big fan, and we think it’s going to help the mobility play.”