| 翻訳と辞書 |
| List of UWB channels ： ウィキペディア英語版 |
List of UWB channels
This List of Ultra-wideband (UWB) Channels describes the physical bands and TFC codes defined in the WiMedia Alliance's PHY specification,〔(WiMedia Alliance downloadable MAC and PHY specifications )〕 as well as their link to the logical channels used in the higher layers such as the Wireless USB driver.
==Spectrum Definition==
Many countries have allocated spectrum for UWB use, with various restrictions and power output limits. The standardized output level for UWB communications is The WiMedia Alliance has defined fourteen 500-MHz bands to divide up the 3.1-10.6 GHz spectrum allocated for Ultra-Wideband communications in the U.S. in 2002.
Many countries had already allocated some spectrum <6 GHz for other uses such as GPS and satellite communications and therefore desired a way to protect those existing devices and applications while allocating additional spectrum for UWB communications, with the idea that UWB devices would avoid the traditional transmitters when they came into geographical proximity or radio range. DAA stands for “Detect and Avoid” and is a similar technique to cognitive radio that was defined for this legacy coexistence. Cognitive radio attempts to detect “primary users” and switch communications to another unused channel. Cognitive Radio is often in the news for trying to make use of the “White Space” between legacy TV broadcast channels. DAA is different in that UWB communications continue on the same band, but actually notch out the transmit spectrum around the legacy channel, so that they don’t interfere but can make use of the channel. The requirement of DAA was placed on the Band Group 1 spectrum by the E.U. and others in 2006 with an implementation deadline of Dec 31, 2010. Due to the U.S. recession and financial difficulties for the UWB developing companies, there was less pressure on the E.U. to exactly define how silicon should implement DAA and companies have not fully implemented DAA. Therefore, devices with global regulatory certification usually use BG3 and BG6 since those bands do not have a DAA requirement. However, China did formally extend their DAA enforcement deadline to Dec 31st, 2013 for Bands 1, 2, and 3〔(China official notice delaying DAA enforcement in BG1 to Dec 31st, 2013. )〕 and South Korea formally extended their DAA enforcement deadline to Dec 31st, 2016 for Band 3.〔(South Korea official notice delaying DAA enforcement in Band 3 to Dec 31st, 2016. )〕
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「List of UWB channels」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|