Talk:Ultra-wideband
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[edit] Call for papers
Do not post them here. --Adoniscik (talk) 02:44, 5 March 2008 (UTC)
- Further information: WP:ADVERTISING
[edit] Impulse Radio and UWB
I notice that there is a redirect from "Impulse radio" to the UWB page. Is there any difference in what the two terms refer to? I do find one mention of "impulse radio" in the article, but it doesn't seem to be explained very well. Mas2265 21:06, 6 July 2006 (UTC)
- As I understand it, UWB is usually implemented by impulse radio. --Apoc2400 06:48, 28 July 2006 (UTC)
- There are two separate implementations of UWB today: multiband OFDM and impulse radio. The section about advantages is not very NPOV: one example is that the GPS system uses narrowband signalling, but is still used for positioning.Mossig 09:35, 29 October 2006 (UTC)
- Good point. I'll try to put some qualifiers in there.Qz27 09:28, 31 October 2006 (UTC)
- There are two separate implementations of UWB today: multiband OFDM and impulse radio. The section about advantages is not very NPOV: one example is that the GPS system uses narrowband signalling, but is still used for positioning.Mossig 09:35, 29 October 2006 (UTC)
Ultra-wide band refers to the spectrum used, independent of signalling, modulation, codeing, etc. "Impulse Radio" refers to a signalling technique where symbols are constructed with pulses of very short duration with occupied bandwidth inversly proportional to pulse duration (shorter=more bandwidth : under 2ns for a 500MHz bandwidth) There have been quite a few implementations of UWB systems in the last 10 years. Early work was focused on pulse based systems.
The FCC Report and Final Order on UWB issued in 2002 gave a more general definition for UWB, leading to alternatives exploiting multiple bands and more modulation techniques. Ultimately a multi-band OFDM technique became the basis for the WiMedia (ECMA-368) high data rate (480Mbps) standard. An impulse based high-rate standard (DS-UWB)had been championed but has ultimately fallen dormant.
The IEEE P802.15.4a amendment defines an UWB PHY which is an impulse radio. The purpose of P802.15.4 is low data rate, low power, low cost systems. The Task Group 4a was created to add precision ranging capability. Impulse UWB is advantageous for accurate time-of-flight measurment. The 4a ammendment is now in final stages of IEEE publication. The standard defines a UWB PHY with modulation using pulse position and polarity, approx. 500MHz chip rate, multiple data rates (different chips/symbol), with forward error correction, multiple operating bands and bandwidths, and a number of optional features. The nominal data rate for 4a is 1Mbps with optional rates up to 25Mbps.
BTW the FCC rules allow multiple UWB bands, with different masks, throughout the spectrum, not just 3.1-10GHz. The FCC has approved numerous systems that operate below 1GHz, for example. —The preceding unsigned comment was added by 64.74.213.146 (talk) 15:17, 25 April 2007 (UTC).
[edit] UWB Radar?
Why isn't there more information on ultra-wideband radar? At least there should be a disambiguation page, since UWB radar is probably considered a more mature technology (being applied commercially in ground-penetrating radar and militarily in foliage-penetrating radar). Granted, UWB radar isn't as sexy as UWB communications, but how come the whole concept of UWB in wikipedia is focused just on the communications aspects? —Preceding unsigned comment added by Robotbeat (talk • contribs) 03:12, 10 March 2008 (UTC)
