無(wú)線技術(shù)簡(jiǎn)介ppt課件-資料下載頁(yè)
2025-01-19 22:06本頁(yè)面
【正文】 y Choose a Wireless LAN? ? The scalability of a work refers to the work’s ability to change as needed to meet expanding needs of an anization or home. ? Network models and standards provide work designers, installers, and users with a certain level of interoperability. ? Portability refers to a device’s capability to move from one standardsbased working environment to another. 143 The Wireless Networking Market ? Most wireless devices have a fairly limited and narrowly defined application, but many can be adapted to meet other applications. ? The markets for wireless devices are: mobile personal devices, wireless working devices, RFID devices, health and medical care devices, and mercial applications. ? Today’s wireless personal devices include enough processing power and storage to replace the laptop and notebook puters of not so long ago. ? The general classes of WLAN devices are: NICs and work adapters, access points, WLAN switches, print servers, wireless routers, wireless bridges, wireless repeaters, and antennae. 144 The Wireless Networking Market ? RFID systems have the capability to retrieve and store information in devices called RFID tags using wireless munications. ? Tracking and monitoring patients, as well as several embedded applications, using wireless munications technology are viewed as ways in which hospital stays and the cost of medical care can be reduced. ? The potential for applications of wireless munications technology in manufacturing, retail, and service industries is virtually unlimited. 145 Wireless Networking Issues and Constraints ? Within the ., the RF spectrum is divided by the FCC into a series of bands, which are allocated to specific usages or purposes. ? The two unlicensed bands specified in the WLAN standards are ISM and UNII. ISM is allocated to the GHz to GHz band and UNII is allocated to the GHz to GHz band. ? RFI is caused by a variety of environmental and electromagic sources. The sources for RFI can be grouped into two general categories: broadcast and electrical. ? Security is often the reason panies and users are reluctant to install a wireless work. ? A link between human ailments and the RF transmissions of WLAN devices has not yet been claimed or refuted.
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