主题：【原创】聊聊wifi手机 -- ragtime

Fraser Lovatt

23 April 04

One thing is for certain – demand for wireless broadband is going to increase rapidly in the US. However, perceived competition between the three main access technologies means that many companies don't know how to meet that demand.

WiFi, WiMAX and 802.20 are three technologies for providing broadband network connections wirelessly, and it's difficult to tell which one to back in this race.

WiFi is well established, has a reasonably large installed base and is in use globally. As McDonalds have already named their WiFi provider, you can tell it's reached mainstream.

WiMAX is backed extensively by Intel and Nokia, and is rapidly emerging as a favourite, though cards employing the technology and WiMAX-enabled laptops are not expected to reach the market until 2007.

WiMAX, based on the 802.16 standard, has huge bandwidth – typically more than 30 times that of 3G data services – and it allows subscribers to receive broadband network access simply by attaching a receiver to their home. This method is being trialled by BT in rural areas as an alternative to digging up fields. The standard is also suitable for people on the move as WiMAX can be used in vehicles up to a speed of 150 Km/h.

The 802.20 wireless networking standard will let you travel at 250 Km/h and still keep a network connection, and so is ideal for deployment on high speed trains.

There are some overlaps between the two technologies, but they are not meant to compete. WiMAX is intended for fixed locations like houses, or a mobile user with a PDA or laptop. 802.20 is intended for high-speed mobility, and can be overlaid on top of an existing WiMAX network.