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Weightless is the name of a set of LPWAN open wireless technology standards for exchanging data between a base station and thousands of machines around it. These technologies allow developers to build Low-Power Wide-Area Networks (LPWAN). There are currently two published Weightless connectivity standards, Weightless-N and Weightless-W. Weightless-N uses ultra narrow band technology operating in licence exempt sub 1GHz spectrum in what is commonly known as the Industrial, Scientific and Medical (ISM) bands. In Europe this includes a range of frequencies around 868MHz; in North America around 915MHz. Weightless is managed by the Weightless SIG, or Special Interest Group, which was revealed to the public on 7 December 2012. An inaugural event for industry was held at the Moller Centre in Cambridge, UK by Cambridge Wireless on Friday, 30 September 2011. Representatives – mainly engineers – from many companies from around the world attended. Presentations were given by Neul, Landis+Gyr, Cable & Wireless, and ARM.〔 〕 The intention is that devices must be qualified by the Weightless Special Interest Group to standards defined by the SIG. Patents would only be licensed to those qualifying devices; thus the protocol, whilst open, may be regarded as proprietary. == Name and logo == The name Weightless was chosen to reflect the lightweight nature of the protocol, meaning that the overhead per transmission is minimised for devices that need to communicate just a few bytes of data. The Weightless logo is trademarked and appears as uppercase letters with the 'W' appearing in the top-right corner of a light blue box that has a solid blue line above it. One of the presenters at the inaugural SIG event in September 2011 stated jokingly, in reference to cellular communication standards, "''Weightless is not 1G, 2G, 3G or even 4G – it is ZERO G''". 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「Weightless (wireless communications)」の詳細全文を読む スポンサード リンク
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