Long-awaited product certifications due from the WiMax Forum will soon see the light of day, a little bit later than expected, according to the industry organization.

The group expects to announce the first certifications of WiMax products in mid-January at a conference in California, said Mo Shakouri, board member and vice president of the WiMax Forum and chairman of its marketing working group. Testing may be completed by the end of the year or the early part of January, he said. The forum had been predicting the first stamps of approval would be handed out by the end of this year.

The latest delay, though expected to be brief, comes on top of a series of missed expectations and extravagant claims that have helped raise skepticism about the technology's potential. WiMax is designed to deliver speeds comparable to DSL (Digital Subscriber Line) and cable modem services over a wireless network that reaches at least a few kilometers. With Wi-Fi networks already available in many locations and 3G (third-generation) cellular data systems being rolled out across metropolitan areas in the U.S., Europe and Asia, some industry observers think it may be too late for another emerging technology to stake a claim.

Organizing WiMax product testing, which will be divided into several waves and require interoperability of products from multiple vendors, played a role in the delay, Shakouri said. With the groundwork now in place, he expects subsequent waves of certification to go more quickly.

The certifications due next month are strictly for fixed WiMax products based on the IEEE 802.16-2004 specification, which isn't intended for use while in motion. The standard that will bring mobility, IEEE 802.16e, was approved less than a month ago, and certified products aren't expected until at least 2007.

Product certification is important to ensure interoperability among vendors' products, according to vendors and service providers. Mix-and-match products should fuel competition and drive down prices, in addition to allowing carriers to invest in WiMax knowing that they won't be tied to one vendor's products, they said.

The WiMax Forum expects to announce the certification of at least three products at the Wireless Communications Association's International Symposium & Business Expo, which will run Jan. 17 to Jan. 20. Those results will come out of the first wave of testing, in which equipment will be certified to comply with the 802.16-2004 standard and interoperate at the level of the air interface, Shakouri said.

Specifically, they will probably be products that use TDD (time-division duplexing), one of two basic approaches being used in WiMax products. Those using FDD (frequency-division duplexing) would follow later, he said. Higher level features, such as mechanisms for ensuring quality of service for voice and other delay-sensitive applications, will be certified in the second wave of approvals, he said. The first of those certifications is expected by the middle of 2006.

All the products being considered now would use radio spectrum in the 3.5GHz range, which can be licensed for commercial services in much of the world but not in the U.S., Shakouri said. Testing of products that use the 5.8GHz band, which is available as unlicensed spectrum and now used for IEEE 802.11a wireless LANs, will come later, he said.

Shakouri acknowledged that high expectations and some confusion have dogged the group's efforts. "We need to do a better job of communicating the different road maps and activity so that it doesn't become confusing in the marketplace," he said.

The bigger issue with new technologies is how soon the final, approved version gets into testing in the real world, said IDC wireless analyst Abner Germanow.

"You can do a lot of work ... within the confines of knowing what the technology should look like, but as a service provider or even an enterprise, you really need to get the technology out in the field," Germanow said. However, a delay of less than three months would probably have little impact on the size of the WiMax market in three years, he said.

Aperto Networks, which is putting its products up for certification in the first wave, is confident its products will comply with the standard and interoperate among at least two other products, said Dean Chang, director of product management at Aperto and chairman of the WiMax Forum's Service Provider Working Group. Interoperability was already demonstrated at "plugfest" events, he said.

For vendors, the danger of missing target dates for standardization is a gap in revenue while service providers hold off on buying pre-standard gear while waiting for the approved equipment to be available, Chang said. However, he doesn't believe a delay on the first WiMax certifications until January will hurt the market.