bluetooth蓝牙技术(这是每年复试都有的)描述.doc

What is Bluetooth?什么是蓝牙 Bluetooth is a universal radio interface in the 2.45GHz frequency band that enables portable electronic devices to connect and communicate wirelessly via short-range, ad hoc networks. Each unit can simultaneously communicate with up to sever other units per piconet. Moreover, each unit can simultaneously belong to several piconets. 　　What is Bluetooth Technology？ 　　Bluetooth technology which apart from Ericsson, has gained the support of Nokia, IBM, Toshiba, Intel and many other manufacturers 　　eliminates the need for wires, cables and connectors for and between cordless or mobile phones, modems, headsets,PDAs, Computers, printers, projectors, local area networks, and so on, and paves the way for new and completely different devices and applications.Technology Characteristics 　　1Ms/s symbol rate exploits maximum available channel bandwidth 　　Fast frequency hopping avoids interference 　　Adaptive output power minimizes interference 　　Short data packets maximize capacity during interference 　　Fast acknowledge allows low coding overhead for links 　　CVSD （Continuous Variable Slope Delta Modulation） voice coding enables 　　operation at high bit- error rates 　　Flexible packet types supports wide application range 　　Air interface tailored to minimize current consumption 　　Basic Technical Information—Based upon a small , high performance integrated radio transceiver ,each of which is allocated a unique 48-bit address derived from the IEEE 802·standard . 　　Operate in the unrestricted 2.45GHz ISM free band, Which is available globally although slight variation of location and width of band apply 　　Range set at 10m to optimize for target market of mobile and business user 　　Gross data rate 1Mbit/s with second generation plans to increase to 1Mbit/s 　　One-to-one connections allow maximum data transfer rate of 721kbit/s （3 voice channels） Uses packet switching protocol based on frequency hop scheme with 1600 hops/s to enable high performance in noisy radio