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The Unlicensed National Information Infrastructure (U-NII)〔("15.07.2005, Heise: 5 GHz WLAN to be available all over Europe" www.heise.de )〕〔("Cisco: Glossary" www.cisco.com )〕 radio band is part of the radio frequency spectrum used by IEEE-802.11a devices and by many wireless ISPs. It operates over four ranges: *U-NII Low (U-NII-1〔("Dynamic Frequency Selection for 5 GHz WLAN in the US and Canada" www.cisco.com )〕): 5.15-5.25 GHz. Originally limited to indoor use only. Regulations required use of an integrated antenna, with power limited to 50 mW.〔(FCC 15.407 as of 2014 - hallikainen.com )〕 Rules changed in 2014 to permit outdoor operation, maximum fixed power 1 watt, maximum fixed EIRP 4 watts (+36 dBm) point-to-multipoint, 200 watts (+53 dBm) point-to-point. () However, strict out-of-band emission rules limit practical point-to-point power to lower levels. *U-NII Mid (U-NII-2〔): 5.25-5.35 GHz. Both outdoor and indoor use, subject to Dynamic Frequency Selection (DFS, or radar avoidance). Regulations allow for a user-installable antenna.〔(FCC-03-287A1.doc )〕 Power limited to 250 mW〔 *U-NII Worldwide (U-NII-2e): 5.47-5.725 GHz. Both outdoor and indoor use, subject to Dynamic Frequency Selection (DFS, or radar avoidance).〔 Power limited to 250 mW.〔 This spectrum was added by the FCC in 2003 to "align the frequency bands used by U-NII devices in the United States with bands in other parts of the world".〔 The FCC currently has an interim limitation on operations on channels which overlap the 5600 - 5650 MHz band.〔("15E, Dynamic Frequency Selection, DFS, DFS Approval" fcc.gov )〕 *U-NII Upper (U-NII-3〔("What's New With Unlicensed National Information Infrastructure (U-NII)" )〕): 5.725 to 5.850 GHz. Sometimes referred to as ''U-NII / ISM'' due to overlap with the ISM band. Regulations allow for a user-installable antenna. Power limited to 1W〔 Wireless ISPs generally use 5.725-5.825 GHz. U-NII is an FCC regulatory domain for 5- GHz wireless devices. U-NII power limits are defined by the United States CFR Title 47 (Telecommunication), Part 15 - Radio Frequency Devices, Subpart E - Unlicensed National Information Infrastructure Devices, Paragraph 15.407 - General technical requirements. Regulatory use in individual countries may differ. The European HiperLAN standard operates in same frequency band as the U-NII. == 5 GHz (802.11a/h/j/n) == ''Except where noted, all information taken from Annex J of IEEE 802.11-2007 modified by amendments k, y and n. Because countries set their own regulations regarding specific uses and maximum power levels within these frequency ranges, it is recommended that local authorities are consulted as regulations may change at any time.'' In 2007, the FCC began requiring that devices operating in channels 52, 56, 60 and 64 must have Dynamic Frequency Selection (DFS) capabilities. This is to avoid communicating in the same frequency range as some radar. In 2014, the FCC issued new rules〔http://www.fcc.gov/document/5-ghz-unlicensed-spectrum-unii〕 for all devices due to interference with government weather radar systems. Fines and equipment seizure were listed as punishment for non-compliance. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「U-NII」の詳細全文を読む スポンサード リンク
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