Global telecoms operators must make "critical decisions" about 4G strategies as mobile WiMax (802.16e) moves from trials to real-world network deployments.

A new study from ABI Research suggests that mobile operators and other service providers are planning mobile WiMax networks all over the world, mainly in the 2.5GHz and 3.5GHz bands.

"The mobile wireless industry is in a state of major change as mobile operators decide which IP-OFDMA path they will take for their 4G networks," said ABI principal mobile broadband analyst Philip Solis.

"The new and unproven (on a large commercial scale) mobile WiMax has positioned itself against the potential Goliath that Long Term Evolution (LTE) is expected to become."

The research firm forecasts "substantial numbers" of WiMax subscribers worldwide, more than 95 million using customer premises equipment devices by 2012, and almost 200 million using mobile devices, with some overlap between the two.

Solis said that, while WiMax equipment interoperability certification timelines have slipped somewhat, and LTE benefits from having evolved out of the widely-deployed GSM technology, WiMax has at least a two-year headstart in reaching the market.

The analyst noted that major semiconductor and equipment makers, with the exception of Qualcomm and Ericsson, are staking out their positions for this emerging sector, while operator enthusiasm, led by Sprint and Clearwire in the US, is rising sharply.

Vodafone is looking to WiMax for some of its newer markets such as the Middle East and Eastern Europe, and BT and Telecom Italia Mobile are also showing interest.

ABI Research understands that another as yet unnamed "major European mobile operator" is "seriously considering" WiMax.