Talk:Ultra-wideband

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Call for papers[edit]

Do not post them here. --Adoniscik (talk) 02:44, 5 March 2008 (UTC)

Further information: [[WP:ADVERTISING]]

Impulse Radio and UWB[edit]

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)

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).

UWB Radar?[edit]

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 (talkcontribs) 03:12, 10 March 2008 (UTC)

forward error correction[edit]

This article currently claims

Current forward error correction technology, as demonstrated recently in some very high data rate UWB pulsed systems (like Low density parity check code) can--perhaps in combination with Reed–Solomon error correction--provide channel performance very closely approaching the Shannon limit (See Shannon–Hartley theorem).

I agree that "Current forward error correction technology, ... can ... provide channel performance very closely approaching the Shannon limit". But that is true for just about any communication system; it has little to do with UWB in particular.

Has someone actually demonstrated a UWB system that used Low density parity check code or Reed–Solomon error correction or both? Or is this merely theoretically true, as implied by the "perhaps"?

And I am mystified at "forward error correction technology ... perhaps in combination with Reed–Solomon error correction". Since Reed–Solomon error correction is a kind of forward error correction, that's like saying "electric light technology ... perhaps in combination with electric light bulbs".

Could someone clarify this article, adjusting sentences like this to make them easier to understand? --68.0.124.33 (talk) 02:28, 4 August 2008 (UTC)

Yes, you could.- (User) WolfKeeper (Talk) 02:42, 4 August 2008 (UTC)
Yes, someone has actually demonstrated a UWB system that uses Reed-Solomon error correction.
Someone else demonstrated a OFDM system that uses LDPC in combination with Reed-Solomon.
I agree that paragraph is confusing.
I suspect that paragraph is an attempt to summarize page 3 of the reference at the end of that paragraph.
I tried to clarify and added more references that say the same thing -- with a few more details on the above two systems. --DavidCary (talk) 19:47, 16 January 2013 (UTC)

Latest Band Group Usage[edit]

Hi,

Does anyone have information on the latest usage of the various Band Groups around the world? I'm specifically interested in BG6 adoption. Thanks.

Tomkost (talk) 17:03, 26 January 2010 (UTC)

Proposed Updates, Jan 2011[edit]

My company is working on high data-rate communications with UWB. There are many challenges, but I agree that some of the info on this Wiki UWB page seems out of date. I'd like to propose several changes, see if anyone has any issues with them over the next month, then I'll update the page.

  1. I see lots of application for communications, therefore include that in summary paragraph at top. Second summary paragraph mentions possible conflicts with existing systems, but I thought that was determined not to be the case before the FCC opened the spectrum in 2002, stating that the rise in noise seen by traditional transmitters would not be significant.
  2. I've done a search of FCC filings and found >120 devices that have received certification.
  3. Will update regulatory status to include China, Korea, Japan, EU. Australia currently in flux. Since WiMedia Alliance is disbanded, I'll directly upload their last regulatory status picture from Jan 2009 when China finished regulations.
  4. I'm going to create a new "List of UWB Channels" page similar to "List of WLAN Channels" to make all of the channel/band/TFC linkage clearer since this is something we've struggled to understand.

spazvt (talk) 12:34, 23 January 2011 (UTC)

Difference from spread spectrum[edit]

This sounds like the old (and still relevant) ideas from Spread spectrum. Is there a key difference? Can ultra-wideband be considered a type or a subset of spread spectrum? I think this would be good material to add to the main page. Lavaka (talk) 01:17, 2 March 2011 (UTC)

Antenna design?[edit]

Given that most antenna designs (eg normal dipole) are narrow band, should there be some comments about ultra wideband antennas eg spiral designs - http://www.antenna-theory.com/antennas/travelling/spiral.php or other small element planer designs( http://www.researchgate.net/profile/Hans_Schantz/publication/4056610_Introduction_to_ultra-wideband_antennas/links/00b7d52a8a5d128046000000.pdf , http://www.piers.org/piersonline/pdf/Vol2No6Page544to549.pdf )

115.64.210.168 (talk) 10:05, 11 January 2015 (UTC) Aart Bluestoke