Whereas 802.11b technology, which utilizes the 2.4GHz spectrum, is designed to cast a relatively narrow bandwidth...
over a roughly 300 foot area, 802.15.3 is structured to offer an extremely wide bandwidth over a much more limited area. It is for this reason that 802.15.3 is classified as an 'ultra wideband' wireless technology, as opposed to generic Wi-Fi. Not only is UWB capable of shuttling multimedia-heavy data at speeds in excess of 100M bits/sec, but it is also more capable than Wi-Fi when it comes to penetrating walls and physical barriers, at least over its short-distance transmission area.
The data rates vary among different wireless alternatives (802.11b vs. 802.11g vs. UWB and so on) because of the assigned frequency on which these signals travel, the power requirements, and the techniques used to transfer information. For example, Bluetooth transmits on the same frequency as 802.11 systems (2.4GHz), but relies on much lower power requirements than Wi-Fi, so the range and overall speeds are limited. (We might add that there are plans in the works to unveil a 100 Mbps version of 802.11 at some point, but back to 802.15.3 and UWB!)
Since UWB is restricted when it comes to longer-range wireless communications, initial uses will be confined to consumer entertainment (wireless stereos and high-definition television), automotive collision systems, medical imaging systems, construction applications (ground-penetrating radar), law enforcement applications (peering through buildings and walls), and peer-to-peer networking. You should actually see first UWB products sometime late next year, and certainly a raft of compatible devices by Christmas 2005.
But, UWB is not the only personal area networking (PAN) game in town. There is also a technology called ZigBee (802.15.4), which utilizes a variety of licensed and unlicensed bands worldwide, operates on extremely low power, and is positioned for control and remote management applications.