Ultra wideband falls under the category of wireless PAN(802.15). After FCC allowed the use of 3.1-10.6GHz for UWB it has become a hot segment. IEE802.15.4 addresses low-speed and IEE802.15.3 addresses higher speed UWB communication. When IEEE802.11 was launched, it was thought it will become the universal solution for home networking. UWB is trying to fill the void where 802.11 could not deliver. 3.1-10.6GHz is not dedicated to UWB, UWB has to co-exist with any other licensed communication in this band. For example IEEE802.11a is licensed at 5GHz. UWB
achieves this goal because of low power transmission or choosing not to transmit in the licensed bands.
There are 2 schools of thought on the modulation scheme to employ for UWB. One is CDMA based and is lead by Motorola/extreme spectrum. The other is OFDM(Orthogonal Frequency Division Multiplexing) based which has a lot of companies supporting it. The idea of OFDM was borrowed from 802.11a. Inspite of greater support and majority in IEEE, OFDM has not been able to get 75% votes required to make it a standard. Proponents of OFDM have formed their own alliance called MBOA and are developing standards in that organization. These standards are almost being finished and will be wrapped up in early 2005. All the OFDM products will comply to these standards.
I will try to explain further by using a Question-Answer type format below:
What are the advantages of UWB compared to 802.11?
UWB can operate at lower power and higher speeds than 802.11. This is mainly because of having a wider band available for transmission than 802.11. Higher speeds are achieved only if distance is shorter than around 20m. Speeds of around 300Mbps are targeted for UWB. UWB is not meant to replace 802.11. From a computer point of view if 802.11 replaces the ethernet connection then UWB is meant to replace USB(connections to mouse and other peripheral devices).
What is the difference between 802.15.3 and 802.15.4?
802.15.4 is lower-rate and is typically used for applications like GPS(location estimation). 802.15.4 can estimate location within a small error. 802.15.3 is for communication.
What are some of the applications where 802.15.3 will be used?
High rate communication will enable it to be used for communicating images and multimedia. For example plasma TV, Home theater speakers. Low-power capabilities will enable it to be used in battery operated consumer electronics like digital cameras, camcorders, ...Wireless USB is a standard that is being developed to incorporate UWB.
What are some of the leading companies developing UWB products?
Extreme spectrum (bought by motorola), Alereon communications(originally time domain), Stoccato communications(originally discrete time), WiQuest(started by some of my colleagues from texas instruments), Pulse Link, Appairent, TPP, Wisair, General Atomics, siworks.....
When will UWB products be available?
extremespectrum is already offering its trinity chipset.Chips based on OFDM are not expected 2005. Products are expected in 2006. Some cores are currently available from appairent, TPP, siworks. Wisair is currently offering a transceiver chip. Staccato communications is currently offering an UWB development platform.
Do UWB and 802.11n compete?
Yes to some extent. 802.11n is more on the networking side.