Comment WiMAX is another specification that has come out of the Institute of Electrical and Electronic Engineers (IEEE) in the US, like Wi-Fi which comes under the 802.11 group. There are two variants of WiMAX, 802.16d which covers fixed installations and 802.16e covering mobile use.
Fixed means point-to-point or point-to-multipoint links, for example, connections to buildings that don't move, while mobile is for laptops and covers users moving between base stations - rather like a cellular network.
The technology behind WiMAX actually works, the specification has taken a while to get to fruition but that's helped it in terms of making sure the bugs are out and it can be used in real life.
Many of the issues that plague Wi-Fi networks just can't happen in WiMAX. Networks can grow, users still maintain usable bandwidth, and interference just doesn't occur. WiMAX can easily achieve a usable 75Mb/s across a wireless link.
The original WiMAX specification allowed frequencies in the range of 2GHz to 60GHz, but it's almost impossible to produce radio equipment using commercial processes on silicon that work at the higher end. A modified specification was then introduced, known as 802.16d-2004, which reduced the frequency range to between 2GHz and 11GHz, which is much easier to support on silicon. This is what's known as WiMAX today.
The one thing WiMAX mandates is that it uses spectrum all to itself, so someone running a WiMAX network, so no one else can run another network on the same frequency. The network can extend to many basestations which interoperate with each other, and there can be many users utilising the network.
WiMAX has no in-built interference protection. It will assume any other network it comes across is part of the same network and, if it isn't, the network is likely to die, resulting in horrendous data loss.
Wi-Fi on the other hand is explicitely designed to co-exist with other Wi-Fi networks. If there is interference from another WiFi network, each will try and ignore the other or at least minimise the interference they cause each other.