Big ideas are at their best when they're, well, big. WiMAX, a big idea backed by Intel (NASDAQ:INTC) and Sprint Nextel (NYSE:S), among others, got bigger yesterday, when three vendors, including Clearwire (NASDAQ:CLWR), successfully tested roaming in Taiwan, according to the WiMAX Forum.

The test is a breakthrough for two reasons:

  1. It proves that WiMAX is capable of becoming not only a wireless broadband standard, but also a cellular telephony alternative.
  2. It gives disparate providers reason to unite, which could attract further investment in WiMAX networks globally.

Investors are more concerned with the second point than the first, and for good reason: WiMAX's greatest challenge is that there is no commonly agreed-upon spectrum for deployment. That problem can now be addressed via the sorts of roaming workarounds tested in Taiwan this week.

What's more, Mobile WiMAX is a common technical standard. Cisco's (NASDAQ:CSCO) WiMAX routers should play nicely with Alvarion's (NASDAQ:ALVR) BreezeMax equipment. The bigger issue, network integration, could become easier to solve now that the WiMAX Forum is actively promoting roaming via a website: wimaxroaming.org.

But the clock is ticking. Both AT&T (NYSE:T) and Verizon (NYSE:VZ) back a competing technology known as LTE, which stands for Long-Term Evolution. LTE promises to merge high-speed data access with high-quality telephony, but do so via legacy carrier networks. AT&T has said it plans LTE deployments beginning in 2011.

WiMAX today is a bigger idea this week than it was last week, but its race to beat LTE is anything but over.

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Fool contributor Tim Beyers owned shares of Alvarion at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Twitter as @milehighfool. The Motley Fool is also on Twitter as @TheMotleyFool. The Fool's disclosure policy lives life without wires, and suggests you do the same.