Editing Ultra-wideband (section)

== Regulation ==
In the U.S., ''ultra-wideband'' refers to radio technology with a [[Bandwidth (signal processing)|bandwidth]] exceeding the lesser of 500&nbsp;MHz or 20% of the arithmetic [[center frequency]], according to the U.S. [[Federal Communications Commission]] (FCC). A February 14, 2002 FCC Report and Order<ref>{{Cite web |url=http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-48A1.pdf |title=Archived copy |access-date=2006-07-20 |archive-date=2006-03-21 |archive-url=https://web.archive.org/web/20060321184536/http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-02-48A1.pdf |url-status=dead }}</ref> authorized the unlicensed use of UWB in the frequency range from 3.1 to 10.6&nbsp;[[Hertz|GHz]]. The FCC power [[spectral density]] (PSD) emission limit for UWB transmitters is −41.3&nbsp;dBm/MHz. This limit also applies to unintentional emitters in the UWB band (the [[Title 47 CFR Part 15|"Part 15"]] limit). However, the emission limit for UWB emitters may be significantly lower (as low as −75&nbsp;dBm/MHz) in other segments of the spectrum.

Deliberations in the [[International Telecommunication Union]] Radiocommunication Sector ([[ITU-R]]) resulted in a Report and Recommendation on UWB{{Citation needed|date=June 2009}} in November 2005. [[UK]] regulator [[Ofcom]] announced a similar decision<ref>{{Cite web |url=http://www.ofcom.org.uk/consult/condocs/uwb_exemption/statement/statement.pdf |title=Archived copy |access-date=2007-08-09 |archive-date=2007-09-30 |archive-url=https://web.archive.org/web/20070930031512/http://www.ofcom.org.uk/consult/condocs/uwb_exemption/statement/statement.pdf |url-status=dead }}</ref> on 9 August 2007.

There has been concern over interference between narrowband and UWB signals that share the same spectrum. Earlier, the only radio technology that used pulses was [[spark-gap transmitter]]s, which international treaties banned because they interfere with medium-wave receivers. However, UWB uses much lower levels of power. The subject was extensively covered in the proceedings that led to the adoption of the FCC rules in the US, and in the meetings of the ITU-R leading to its Report and Recommendations on UWB technology. Commonly-used electrical appliances emit [[Electromagnetic interference|impulsive noise]] (for example, hair dryers), and proponents successfully argued that the [[noise floor]] would not be raised excessively by wider deployment of low power wideband transmitters.<ref>{{cite web |url=https://www.dau.edu/cop/e3/resources/ultra-wideband-uwb |title=DAU |website=Defense Acquisition University |access-date=1 June 2024}}</ref>

=== Coexistence with other standards ===
In February 2002, the Federal Communications Commission (FCC) released an amendment (Part 15) that specifies the rules of UWB transmission and reception. According to this release, any signal with fractional bandwidth greater than 20% or having a bandwidth greater than 500&nbsp;MHz is considered as an UWB signal. The FCC ruling also defines access to 7.5&nbsp;GHz of unlicensed spectrum between 3.1 and 10.6&nbsp;GHz that is made available for communication and measurement systems.<ref>{{Cite web |date=2015-12-27 |title=Revision of Part 15 of the Commission's Rules Regarding Ultra WideBand Transmission Systems {{!}} Federal Communications Commission |url=https://www.fcc.gov/document/revision-part-15-commissions-rules-regarding-ultra-wideband-7 |access-date=2023-12-21 |website=www.fcc.gov |language=en}}</ref>

Narrowband signals that exist in the UWB range, such as [[IEEE 802.11a]] transmissions, may exhibit high [[Spectral density#Power spectral density|PSD]] levels compared to UWB signals as seen by a UWB receiver. As a result, one would expect a degradation of UWB bit error rate performance.<ref>{{cite book|last1=Shaheen|first1=Ehab M.|title=Ccece 2010|last2=El-Tanany|first2=Mohamed|year=2010|isbn=978-1-4244-5376-4|pages=1–6|chapter=The impact of narrowband interference on the performance of UWB systems in the IEEE802.15.3a channel models|doi=10.1109/CCECE.2010.5575235|s2cid=36881282}}</ref>