4g知识英文介绍.doc

4 G network mobile communication technology 4G is short for the fourth generation network rmobile communications and technology. combining 3G with WLAN ,the product could tansfer high quality video image,and the quality of carrier image is as the same level with high definition TV. 4G syestem network structure is divided into three layers:Physical network layer,Environment layer among,Appication network layer.The physical network layer provides the access and routing functions ,finished by the combination of wireless and core network format .the environment layer is responsible for these functions:Qos mapping,address transformation and complete management and so on.with the interfaces among the three layers are open,the 4G network make it more easily to develop and provide new appications and service. the fourth mobile communication system with orthogonal frequency division multiplexing (OFDM) for technical core .CFDM's characteristics are highly extensible network structure,good resistance to noise performance and good resistance to many channel interference ability. As a result,it could offer higher quality service and better cost perfomance than current wireless data technology ,and become a better choice for 4G technology.The advantages of 4G: if the 2G and 3G communication is insignificant for the development of Human informationizatiion,then the 4G will give we human beings real communication free , will completely change our way of life and even the social form.Compared with the former technology ,the 4G network will present the following characteristics:1.the communication of 4G is more faster Because the original purpose of people study 4G is to improve the speed of cellular phons and other mobile device of wireless access Internet,the mobiel communication leaves deep impression on publics.The speed of 4G could reach 10Mbps and 20Mbps,even the highest speed can reach 100Mbps per second, which is 10,000 times that of the current mobile phone transmission speed.2.Wider Network spectrum In order to make the 4G transmission information with a 100Mbps speed, communications carriers have to do a lot of research and reform greatly based on 3G network.According to research ,the emerging technology is considered to be that each channel will have 100MHz of spectrum ,equivalent to W-CDMA 3G 20 times as much as the Internet .3.Intelligence higher performance The 4th generation mobile communication of higher intelligence,not only displayed in 4G communications terminal equipment design and operation features intelligence, such as menu and rolling the reliance of the operation will be greatly reduced,but also 4G mobile phone can realize the function of many hard to imagine.For example,with a 4G phone,it will automatically according to the environment ,time,and other factors to set time to remind the master that at this time should do something or shouldn't do something .A 4G phone will help you buy a satisfactory movie tickets ,becuase it could download cinema box office material on to the PDA,and these data will be able to show us the present ticket,seat accurately.What's more , 4 G phones can be seen as a portable television, to watch the live the sports .4.Provide all kinds of value-added services 4 G communications were not based on 3 G communication through simple upgrade and evolution,their core construction technology is different,3G mobile communication system is mainly by CDMA as the core technology,while the 4G's core technology is orthogonal multitasking points frequency technology(OFDM). With this newly technology ,operators can provide wireless regional loop (WLL), digital radio (DAB) heard from aspects of the proliferation of wireless communication services .Taking 3 G communications transitional into consideration,researchers will combine CDMA with OFDM,and the future of the fourth generation mobile communication system shall be equipped with the global roaming, interface open, with multiple network interconnection can, terminal diverse and can smooth transition from the second generation.5.Achieve higher quality of the multimedia communication Although the third generation mobile communication system also can realize various multimedia communication ,The future of 4 G communication can satisfy the third generation mobile communication is still cannot achieve in coverage, the quality and the cost to support the communications of the high speed data and high resolution multimedia services need.The 4G system to provide wireless multimedia communication services will include voice, data, video has a lot of information through broadband channel transmitted, therefore the future of the fourth generation mobile communication system is also known as the "multimedia mobile communication". 5.Cheaper communication costs Compared with other technology,4G communications easier to deploy.And when construct the 4G network system ,communicati。