通信概论论文(国外英文资料).docVIP

通信概论论文(国外英文资料) The rapid development of communication technology has certainly brought us a lot of enjoyment. With the development of data communication and multimedia business requirements, adapt to the mobile data, mobile computing and mobile multimedia operation to the fourth generation mobile communication began to rise, users also have reason to look forward to the fourth generation mobile communication technology will bring us a better future. When it comes to fourth-generation mobile communication technology, it is certainly not clear to many people that this article will introduce the technology in detail from five aspects. The development background of fourth-generation communication technology As we all know, all the development of technology cant achieve overnight, from GSM, GPRS to four generation, needs to evolve, and these technologies can exist at the same time. We all know that the first mobile phones were used analog cellular technology, this technology can only provide regional voice business, and poor results, secrecy performance is not good, the users answer is very limited. Along with the rapid development of mobile phone users to the rapid growth of the traditional communication model already cant satisfy peoples needs for communication, in this case there is a GSM communication technology, the technology using narrowband TDMA, allowed in a radio frequency (i.e., honeycomb) eight group calls at the same time. It is a digital mobile phone system based on European standards that ranges between 900 and 1800MHz, and the 1800MHz system is adopted by the United States. GSM was launched in 1991. By the end of 1997, it had been operating in more than 100 countries, becoming the DE facto standard for Europe and Asia. GSM digital network also has strong confidentiality and anti-jamming, the sound quality is clear, talk on the phone, stable and has large capacity, high frequency resource utilization, open interface, powerful functions, etc. But it can pro