专业英语课程报告专业英语课程告.docVIP

Modern mobile communication technology In now highly the informationization society, the information and the correspondence have become the modern society ?the life?hThe information exchange mainly relies on the computer correspondence, but corresponds takes the transmission method, with the sensing technology, the computer technology fuses mutually, has become the international society and the world economic development powerful engine in the 21st century . In order to adapt the time request, the new generation of mobile communication technology seasonable and lives, the new generation of mobile communication technology is the people said that thirdgenerations core characteristic is the wide band addressing turns on non-gap roaming between the rigid network and numerous different communications systems gains the multimedia communication services. Along with the time progress, the technical innovation, peoples life requests enhancement, the mobile communication technology renewal speed is quite astonishing, almost every other ten year mobile communication technology has a transformation update, from the 1980s ?the mobile phone? to presents 3G handset, during has had two mobile communication technology transformation, transits from 1G AMPS to 2G GSM, from GSM to IMT-2000 (i.e. 3G technology). Knows modern on me the mobile communication technology to have the following several aspect important technology: 1. wideband modulation and multiple access technique The wireless high speed data transmission cannot only depend on the frequency spectrum constantly the expansion, should be higher than the present number magnitude at least in the frequency spectrum efficiency, may use three technologies in the physical level, namely OFDM, UWB and free time modulation code. OFDM with other encoding methods union, nimbly OFDM and TDMA, FDMA, CDMA, SDMA combines the multiple access technique.In the 1960s the OFDM multi-channel data transmission has succeeded uses in Kineplex and t