Until 2009, people could not accurately define 4G communication. Some people say that the concept of 4G communication comes from other wireless service technologies, from wireless application protocol, global pocket wireless service to 3G. Some people say that 4G communication is a research topic beyond 20 10 years. 4G communication is a system in the system, and various wireless technologies can be used. But no matter how people define 4G communication, one thing people can be sure of is that 4G communication may be a more perfect wireless new world than 3G communication, and it can create many applications that consumers can't imagine.
Compared with traditional communication technology, the most obvious advantages of 4G communication technology are call quality and data communication speed. However, in terms of call quality, mobile phone consumers are still acceptable. With the development and application of technology, the call quality of mobile phone in the existing mobile phone network is still improving. The high speed of data communication is indeed a great advantage, and its maximum data transmission rate reaches 100Mbit/s, which is incredible. In addition, due to advanced technology, the cost investment is greatly reduced, and the communication cost of 4G in the future will be lower than that in 2009.
4G communication technology is another evolution of wireless communication technology after the third generation, and its development has a clear goal: to improve the speed of wireless access of mobile devices to the Internet. According to the three-stage development plan of the 3G market, 3G multimedia services will enter the third development stage in 10 years, when the 3G network covering the whole world has been basically established, and more than 25% of the global population will use the third generation mobile communication system. In developed countries, the penetration rate of 3G services exceeds 60%, so a new generation system is needed to further improve the service quality.
In order to make full use of the advanced services brought by 4G communication, people have to rely on various 4G terminals. Many communication operators just saw the huge market potential of future communication, and began to focus on the production of 4G communication terminal products, such as the production of small terminals with high-speed packet communication function, terminals corresponding to video phones and video transmission services equipped with cameras, or special terminals for card data communication matching with computers. With these communication terminals, people's mobile phone users can roam freely and enjoy high-quality communication anytime and anywhere.
Network Structure and Key Technologies of 4G System
The network structure of 4G mobile system can be divided into three layers: physical network layer, intermediate environment layer and application network layer. The physical network layer provides access and routing functions, which is completed by the combination of wireless and core network. The functions of the intermediate environment layer include QoS mapping, address translation and integrity management. The interface between the physical network layer and the intermediate environment layer and their application environment is open, which makes it easier to develop and provide new applications and services, provides seamless wireless services with high data rate and runs in multiple frequency bands. This service can adapt to various wireless standards and multi-mode terminal capabilities, span multiple operators and services, and provide a wide range of services. The key technologies of the fourth generation mobile communication system include channel transmission; High-speed access technology, modulation and information transmission technology with strong anti-interference ability; High performance, miniaturization and low cost adaptive array smart antenna: large capacity and low cost wireless interface and optical interface; System management resources; Software radio, network structure protocol, etc. The fourth generation mobile communication system is mainly based on orthogonal frequency division multiplexing (OFDM). OFDM technology has a highly scalable network structure, good anti-noise performance and multi-channel interference resistance, which can provide wireless data technology with higher quality (high speed and small delay) services and better cost performance, and can provide a better solution for 4G wireless networks. Such as wireless area loop (WLL), digital audio broadcasting (DAB), etc. It is expected that OFDM technology will be adopted. 4G mobile communication provides a technical response to the accelerated growth of broadband wireless connection demand, and provides seamless services for various wireless systems and networks spanning public and private, indoor and outdoor. By providing the best service required by users to the most suitable available network, we can cope with the expected growth of Internet-based communication, add new frequency bands, greatly expand spectrum resources, provide different types of communication interfaces, use network architecture based on routing technology, and develop hardware architecture by using Fourier transform to realize the fourth generation network architecture. Mobile communication will develop in the direction of data, high speed, broadband and higher frequency band, and mobile data and mobile IP are expected to become the mainstream services of mobile networks in the future.