There are so many competing wireless technologies and uncertainties surrounding WiMax that high-tech market research firm In-Stat issued two different WiMax chipset forecasts in its annual WiMax report last week.

If the market variables fall in WiMax's favor, In-Stat projects the market to reach as high as $950 million by 2009. If the variables tumble the other way, the researcher offers a more conservative 2009 market estimate of $450 million.

The figures in the company's report, "WiMax: Wireless Super-Chips," include all flavors of the technology: fixed (802.16-2004) and mobile (802.16e and WiBro, the Korean version of 802.16e).

In-Stat's predictions might seem like a cop-out, but I view them more as an attempt to be realistic, enabling takers to bet based on how circumstances develop. In the wake of the IEEE's approval this month of the 802.16e standard (now formally known as 802.16e-2005), for example, the question looms large whether mobile WiMax will prove a worthy opponent against established cellular technologies. Product interoperability and certification testing of 802.16e-2005 is to start next quarter.

Similarly, three Korean telecom providers are supposed to begin offering WiBro-based mobile services during the second half of next year, but it is not yet clear whether they are on schedule.

Meanwhile, although the WiMax industry has been hyping fixed WiMax technology for years and the WiMax Forum opened its certification lab in July, we haven't heard of any WiMax Forum-certified products yet (and some have argued that this phase of certification is not worth their while). Certified products are expected from the more enthusiastic vendors by year-end, but that milestone is fast approaching.

Without certified products and services based on them, it's tough to predict how the services will do and what the demand for customer equipment will be.

Also, now that mobile WiMax standards have caught up, will fixed WiMax infrastructure providers continue to focus on last-mile services or attempt to quickly build out their still-nascent fixed infrastructures to include 802.16e capabilities?

While 802.16e-2005 is officially an "extension" of 802.16-2004, "mobile WiMax extends fixed WiMax so far that you can't really use your fixed infrastructure for mobile WiMax," says Gemma Tedesco, senior analyst at In-Stat. "And the push is toward getting to mobile WiMax as soon as possible. It's not clear what the fixed infrastructure providers are going to do."