WiMax was the trade name for a family of technologies related to the IEEE 802.16 wireless standards.
WiMax had the potential for long range (5 - 30 miles) and high speeds.
The initial version, based on 802.16a, was designed for fixed (non-mobile) applications only, such as a wireless replacement for home DSL or cable modem service.
Later versions, such as 802.16e, added support for mobility, potentially making WiMax a competitor for certain 3G or 4G cell-phone technologies. In the US, Sprint attempted to use WiMax to do just that.
WiMax was among the first technologies to use OFDM (Orthogonal Frequency Division Multiplexing) for mobile data. OFDM technology was later adopted by more popular standards.
WiMax was deployed at higher frequencies than most mobile phone networks at the time. WiMax technology could operate in the 2.5 or 3.5 GHz licensed bands, or in the 5.8 GHz unlicensed band.
In mobile phones, WiMax was overshadowed and eventually replaced by the competing LTE standard, which enjoyed more success and support globally.