Data Acquisition Web

The emerging 802.16e and 802.20 standards will both specify new mobile air interfaces for wireless broadband. On the surface the two standards seem very similar, but there are some important differences between them. For one, 802.16e will add mobility in the 2 to 6 GHz licensed bands, while 802.20 aims for operation in licensed bands below 3.5GHz.

More importantly, the 802.16e specification will be based on an existing standard (802.16a), while 802.20 is starting from scratch. This means that products based on 16e will likely hit the market well before .20 solutions -- a distinct advantage for the WiMax Forum, the group currently backing 802.16 and its permutations.

The IEEE approved the 802.16e standards effort with the avowed intent of increasing the use of broadband wireless access (BWA) by taking advantage of the "inherent mobility of wireless media." The amendment to 802.16, which is also called the wireless metropolitan area network (MAN) standard, will enable a single base station to support both fixed and mobile BWA. It aims to fill the gap between high data rate wireless local area networks (WLAN) and high mobility cellular wide area networks (WAN).

The 802.20 interface seeks to boost real-time data transmission rates in wireless metropolitan area networks to speeds that rival DSL and cable connections (1Mbps or more) based on cell ranges of up to 15 kilometers or more, and it plans to deliver those rates to mobile users even when they are traveling at speeds up to 250 kilometers per hour (155 miles per hour). This would make 802.20 an option for deployment in high-speed trains. The 802.16e project authorization request specifies only that it will "support subscriber stations moving at vehicular speeds".

There is clearly some overlap between the two standards, but the party line from companies involved in the 802.20 standards effort are not competitive.

Essentially, 802.16e is looking at the mobile user walking around with a PDA or laptop, while 802.20 will address high-speed mobility issues. "802.20 is looking at more ubiquitous coverage ... and that will require a larger footprint."

Some argue that 802.20 is a direct competitor to third-generation (3G) wireless cellular technologies. Operators could deploy 802.20 as an overlay to their existing networks. "They don't have to walk away from what they have."

In the meantime, 802.16e's head start may actually work to 802.20's advantage by whetting users' appetites for mobile access.