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无线局域网产品最早出现在市场上大约在1990年。1997年完成的IEEE 802.11无线局域网标准是无线网络技术发展的一个里程碑。802.11标准除了介绍无线局域网的优点及各种不同性能外,还使得各种不同厂商的无线产品得以互联,802.11标准不久将修订,以引入更高的传输速率。因802.11标准的颁布,使得无线局域网在各种有移动要求的环境被广泛接受,这些包括教育、医疗、仓库及其它各种不同行业,苹果电脑公司宣布其新的iBOOK便携机安装朗讯科技11Mbps无线局域网网卡,标志着无线局域网产品在家用及教育领域迈出了巨大的一步。 IEEE 802.11 IEEE 802.11标准1997版规定无线局域网有三种物理层介质:两种采用射频技术,频带为2400～2483.5MHz(根据各国的规定),另一种是基于光的物理层用红外光来传输。直接序列扩频(DSSS)的物理层提供2Mbps和1Mbps的传输,跳频扩频(FHSS)和红外光物理层规定了1Mbps传输(可选2Mbps),因此,所有符合802.11直接序列扩频的产品均支持2Mbps传输,而一些FHSS产品仅能支持1Mbps传输。更高的传输速率,可同时支持更
Wireless LAN products first appeared in the market around 1990. The IEEE 802.11 wireless LAN standard, completed in 1997, is a milestone in the development of wireless networking technologies. In addition to introducing the benefits and various performance features of wireless LAN, the 802.11 standard also enables wireless products from a wide range of vendors to be interconnected. The 802.11 standard will be revised shortly to introduce higher transmission rates. Because of the promulgation of the 802.11 standard, wireless LANs are widely accepted in a variety of mobile-demanding environments, including education, healthcare, warehouses, and various other industries. Apple Computer announced that its new iBOOK laptop will install Lucent Technologies 11Mbps wireless LAN card, marking the wireless LAN products in the field of home and education has taken a huge step forward. IEEE 802.11 The IEEE 802.11 standard 1997 states that WLANs have three physical layer media: two using radio frequency technology with a frequency band of 2400 to 2483.5 MHz (as per country regulations) and the other based on the physical layer of light using infrared light for transmission. Direct Sequence Spread Spectrum (DSSS) physical layer provides 2Mbps and 1Mbps transmission, frequency hopping spread spectrum (FHSS) and infrared physical layer 1Mbps transmission (optional 2Mbps), therefore, all in line with the 802.11 direct sequence spread spectrum products Both support 2Mbps transmission, while some FHSS products can only support 1Mbps transmission. Higher transfer rate, can support more at the same time