The ITU has designated the radion frequencies used for WiMax as IMT frequencies and has assigned globally harmonised spectrum for use by IMT. 

According to the ITU, the IMT spectrums would be in the following radio frequencies: 450MHz-470MHz band; 698MHz-862MHz band in Region 2 (Americas) and nine countries of Region 3 (Asia/Oceania); 790MHz-862MHz band in Regions 1 (Europe, MEA, Russia) and 3 (Asia/Oceania); 2.3GHz-2.4GHz band; and 3.4GHz-3.6GHz band (no global allocation, but accepted by many countries).
This means that the 450MHz-470Mhz and the 2.3GHz-2.4GHz bands were recognised globally as IMT frequency bands, the frequencies to be used by IMT technologies such as 3G cellular technologies and WiMax, the newest member of the IMT family.
One of the most contentious debates at the World Radio Communications meeting (WRC-07) centred around the 3.4GHz-4.2GHz band, commonly called the C-band, which is used by satellite providers in many countries. Those satellite players fought hard to keep the band being globally recognised as an IMT frequency, arguing that deploying wireless technologies in those airwaves would disrupt their transmissions.
The lower portion of the C-band, 3.5Ghz, is used by WiMax operators around the world. They argue that both wireless broadband and satellite networks can exist together provided adequate safeguards against interference are put in place.
Ultimately, the WRC-07 decided against designating the whole C-band as IMT but the 3.4GHz-3.6GHz band, within which WiMax operates, was recognised and accepted by many countries as suitable for IMT, although it was not given a global allocation.
The US and some countries in the Americas opted out, along with most Asian nations, both sets of countries concerned to protect broadcast satellite services.
However, 14 countries in the Americas and eight in Asia opted into an allocation between 3.4GHz and 3.5Ghz, meaning they could use those frequencies for WiMax or any other IMT technology.
In Europe and Africa (Region 1) there was wider support for inclusion of 3.4GHz-3.6GHz frequencies for IMT use and many countries opted in.
"WiMax and other 4G mobile technologies-and all advocates of technology-neutral regulatory decision-making-received a huge boost by both inclusion in the definition of IMT and in several new IMT frequency bands," comments Wireless Communications Association President Andrew Kreig.