Operators Clearwire International, Tatung InfoComm and VMAX have for the first time demonstrated mobile WiMax global roaming, the WiMax Forum said on Monday.

The demonstration was done at the WiMax Forum Member Conference in Taipei. It used a USB (Universal Serial Bus) modem, a username and password from Clearwire to gain access to both Tatung InfoComm's and VMAX's respective WiMax networks in Taiwan.

The operators talked to each other via Aicent, a third-party roaming exchange provider.

Roaming is key if WiMax is to become more than a national mobile broadband technology, so the demonstration was an important step, according to Richard Webb, directing analyst at market research company Infonetics.

Since Clearwire is one of the few large operators pushing mobile WiMax it can be expected to take the lead on international roaming, he said.

Clearwire is continuing to roll out WiMax service in the U.S., with its high-speed wireless service set go on sale in Chicago in November, it said last week.

Currently, there are about 500 WiMax deployments in 145 countries, according to the WiMax Forum.

Different spectrum is used for WiMax in different parts of the world, presenting a challenge to operators when it comes to achieving global roaming, Webb said.

As competing next-generation mobile broadband LTE (Long-Term Evolution) is getting closer to roll-out, operators need to move WiMax forward, according to Webb.