Mobile communication has become the most developed potential in contemporary communications, the most wide market prospects. At present, there is a considerable mobile communication standard for GSM, CDMA and TDMA, and each branch is seizes the market. Global wireless technology is all kinds of camps, and all manufacturers have continuously launched new technologies to quickly seize the dominance of industry standards. Although the third generation of mobile communication (3G) standards are more powerful than existing wireless technology, the area competition and standard is not compatible. People have begun to call on mobile communication standards to solve compatibility issues with a view to the development of the fourth-generation mobile communication standard. International Telecommunications Union (ITU) has already begun to develop fourth-generation mobile communication standards, and has reached a consensus: combine mobile communication systems with other systems (such as infinite local area networks, W-lan, etc.) to generate 4G technology, 2010 The data transmission rate is previously reached to 100 Mbps to provide a variety of business. The fourth generation mobile communication standard (4G) currently compatible with mobile communication technology is in the industry. Compared with the third generation of mobile communications, the third generation of mobile communications will have a qualitative leap in technology and applications. 4G will be suitable for all mobile communication users, ultimately realize the seamless connection between commercial Wi-Fi, LAN, Bluetooth, broadcast, and TV satellite communications and compatible with each other.
1.1 First generation mobile communication technology (1G)
It is mainly used to simulate technology and frequency division multiple access (FDMA) technology. Due to the limit of transmission bandwidth, the long-distance tour of mobile communication cannot be carried out, which can only be a regional mobile communication system. The first generation of mobile communications has a variety of formulations, my country mainly uses TACS. The first generation of mobile communication has many shortcomings, such as limited capacity, too much system, is not compatible with each other, poor confidentiality, non-high call quality, cannot provide data business, and cannot provide automatic temperature tour.
1.2 Second Generation Mobile Communication Technology (2G)
Mainly used is a digital time division multiple access (TDMA) technology and code division multiple access (CDMA) technology. The main business is voice, and its main feature is to provide digital voice service and low speed data services. It overcomes the weakness of the analog mobile communication system, the voice quality, and confidentiality performance, and can carry out automatic roaming in the province. The second generation of mobile communication replaces the first generation mobile communication system to complete the transformation of the simulation technology to digital technology, but due to the second generation of different formulations, mobile communication standards are not uniform, users can only roam within the same system coverage, Therefore, global roaming cannot be performed, and due to the limited bandwidth of the second generation digital mobile communication system, the application of data services is limited, and the high-rate business such as moving multimedia services cannot be achieved.
1.3 Third Generation Mobile Communication Technology (3G)
3G will have a wider bandwidth with the second generation of mobile communication technologies represented by simulation technology, and the transmission speed is 384K, up to 2m, with bandwidth of 5MHz. Not only can transmit voice, but also transmit data, providing fast, convenient wireless applications, such as wireless access Internet. It is possible to achieve high-speed data transmission and broadband multimedia services to be another main feature of third generation mobile communications. The third generation mobile communication network can combine high-speed mobile access and Internet protocol, and improve wireless frequency utilization efficiency. Global coverage, including satellite, is available, and a seamless connection between services between wired and wireless and different wireless networks. Meet the requirements of multimedia business, providing users with more economical and more rich wireless communication services. However, the third generation of mobile communication is still a regional communication system based on the ground and standard. Although third-generation mobile communication can be thousands of times a thousand times more than the existing transmission rate, it is still unable to meet multimedia communication needs. The provision of the fourth-generation mobile communication system is to meet the needs of providing greater frequency wide demand, meeting the need for high-speed data and high-resolution multimedia services supported by third-generation mobile communications. .
2 Fourth generation mobile communication and its performance
The fourth-generation mobile communication system can be called a Broadband access and distribution network, which has data transmission capabilities of more than 2Mb / s, and the data rate exceeds UMTS, which is supported high-speed data rate (2 ~ 20MB / s). The ideal mode of the connection, the Internet speed is increased from 2Mb / s to 100MB / s, and has automatic switching capabilities between different speeds. The fourth-generation mobile communication system is a multi-functionally integrated broadband mobile communication system, and in terms of business, both the third generation system is different from the third generation system, and will be provided in different fixed and wireless platforms and network operations across different frequency bands. Wireless services, closer to personal communication than third-generation mobile communications. The fourth-generation mobile communication technology can increase the Internet speed to 50 times more than the third generation of mobile technology, and high quality transmission of 3D images can be achieved. 4G information transmission level of 4G mobile communication technology is higher than the number of information transport levels of 3G mobile communication technology. The efficiency of the wireless frequency is much higher than the second generation and third generation systems, and the anti-signal fading performance is better, and the maximum transmission speed will be 100,000 times the current "I-Mode" service. In addition to high-speed information transmission technology, it also includes high-speed mobile wireless information access systems, mobile platform technology, security password technology, and terminal communication technologies, with extremely high security, 4G terminals can also be used as a positioning, alarm, etc. . The 4G mobile phone system downlink speed is 100Mbps, and the uplink speed is 30Mbps. Its base station antenna can transmit a narrower radio wave beam, and can be tracked in user actions, and can process the number of calls. The fourth-generation mobile phone is not only sound quality, but also can perform high-definition image transmission, which will be very wide. In terms of capacity, air division multiple access (SDMA) can be introduced on the basis of FDMA, TDMA, and CDMA, with a capacity of 5 to 10 times. In addition, you can access the Internet in any address broadband, including satellite communication, and provide integrated functions such as positioning timing, data acquisition, remote control outside of information communication. It includes a wide-band wireless fixed access, a wide-band wireless LAN, a mobile broadband system, and interoperability broadcast network (based on ground and satellite systems). Its wide-band wireless LAN (WLAN) is compatible with B-ISDN and ATM, realizes wide-band multimedia communication, forming a comprehensive broadcast network (IBCN), calls via IP. Can fully mobile users can provide 150MB / s high quality image service, implement high quality transmission of three-dimensional images, and three-dimensional virtual reality communications can be performed between wireless users. It can adapt to resource allocation, handling changes, and different environmental environment, with strong self-organizational and flexibility. According to the dynamic and automatic channel conditions of the network, the low yard ratio and the high yield value can coexist, and some of the fixed mobile broadcasting networks or other rules are integrated to implement control of these functional volume distributions. Support interactive multimedia business, such as video conferencing, wireless internet, etc., providing wider services and applications. 4G system can automatically manage, dynamically change your own structure to meet system changes and development requirements. Users will use a wide variety of mobile devices to access to 4G systems, and various access systems combine into a public platform, they complement each other, collaborate with each other to meet different business requirements, mobile network services tend to Diversified, eventually evolve into a multi-industry, multi-sectoral, multi-system bridge to communicate with people. 3 4G system network structure and its key technology
4G mobile system network structure can be divided into three layers: physical network, intermediate environment layer, application network layer. Physical network layers provide access and routing features, which are completed by the combination format of wireless and core networks. The function of the intermediate environment has QoS mapping, address transform, and complete management. The interface between the physical network layer and the intermediate environment layer and its application environment is open. It makes it easier to develop and provide new applications and services, providing wireless services with seamless high data rates, and runs in multiple frequency band. This service can adapt to multiple wireless standards and multi-mode terminal capabilities, including large-scale services. Key Technologies of the fourth-generation mobile communication system include channel transmission; high-speed access technology, modulation and information transmission technology, strong anti-interference, high performance, miniaturization and low cost adaptive array intelligent antenna; large capacity, low cost Wireless interface and optical interface; system management resources; software radio, network structure protocols, etc. The fourth-generation mobile communication system is mainly based on orthogonal frequency division multiplexing (OFDM). The features of OFDM technology are highly scalable network structures. It has good anti-noise performance and anti-multi-channel interference capabilities, which can provide services and better performance prices than current wireless data technology (high rate, time delay). Compare, you can provide a better solution for 4G wireless networks. For example, wireless area loop (WLL), digital audio broadcast (DAB), etc., OFDM technology will be used. 4G mobile communications provides technical response to accelerated growth-wide wireless connections, providing seamless services to a variety of wireless systems and networks across the public and dedicated, indoor and outdoor. By providing the best service required for the most suitable available network, you can cope with the growth of Internet communication, add new frequency bands, to expand the spectrum resources, provide different types of communication interfaces, and use routing technology. The network architecture, with Fourier transform development hardware architecture to achieve the fourth generation network architecture. The mobile communication will be data-based, high speed, broadband, and frequency bands, and mobile data, and mobile IP will become the mainstream business of future mobile networks. 4 Fourth generation mobile communication
To make the fourth-generation mobile communication system can put practical applications, it is necessary to update the existing mobile communication infrastructure, first requiring problems such as mobile IP technology in the wireless system, of course, 4G standard problem. Network layer mobility is the key to 4G mobility management, and mobility typically involves the mobile user of the roaming between different network segments, and the mobility support of the data link layer is usually limited between the same network. Mobile IP represents a simple and upgraded global mobility program. However, for the fourth generation mobile communication system, it lacks support for real-time location management and fast seamless switching mechanism. To resolve these issues, you must adopt a new network structure and management routing program, you need to use an efficient transmission and switching protocol, which must be able to solve the problem of data loss and delay. In addition, the integrated service / RSVP technology (INTSEV / RSVP) and distinguished business technology (Difserv / RSVP) and distinguishing technology (Difserv) used in the mobile IP environment also need to be resolved. In the 4G system, new spectrum resources are developed, providing spectral utilization and selecting appropriate transmission techniques, such as multi-carrier transmission methods, and adaptive equalization, etc. Using RAKE reception, frequency hopping, and Turbo code to enhance the performance of the system, improve the credit ratio; improve the resource and signal quality, dynamic allocation frequency resources and signal transmit power, increase the capacity of mobile communication system, reduce signal transmit power Improve the coverage of communication and support multimedia communication, wireless access broadband fixed network, and roaming between different systems.
5 World pay attention to the fourth generation of mobile communication
At present, the world is actively conducting research and development of 4G technical specifications, with a view to the global 4G specifications. The 4G operational standards will be determined by the International Telecommunication Union (ITU) Telecommunications Standards Bureau. A new generation of wireless communication technology has entered the intensive R & D and marketing stages in developed countries such as US and Japan. New research includes system implementations such as network structures, user switching, and roaming and other mobile environments, thereby achieving a wide range of users, and this technology route is the main idea of designing fourth-generation mobile communication systems internationally. Alcatell, Ericsson, Nokia and Siemens have jointly established world Wireless Research Forum aimed at promoting 4G technology development. US AT & T has studied fourth-generation mobile communication technology in the laboratory, and its research purpose is to improve the rate of cellular phone and other mobile devices wireless access to the Internet. This technology will be released for five years. AT & T has launched a 4G Access network, which can be uploaded with current EDGE technology and downloaded with broadband OFDM technology. At present, the 4G Access network upgrade of AT & T is divided into two phases. The first phase is the software construction of the mobile phone base station. The second phase is estimated to build hardware builds for intelligent antennas after two years. Nortel Network works to make IP's 4G network transmission speed of 20 Mbps, so it is necessary to develop Software Radio, broadband receiver, new power amplifier and other relevant action technology development.
The world's largest telecom infrastructure provider Swedish Ericsson has begun research on the fourth generation of mobile communication standards, and launches the fourth generation of mobile communication systems. It is expected to be officially put into operation in 2011, and the 2012 Olympics can be applied. Ericsson has been studying "4G glasses" in 2011 will also enter the market. Ericsson plans to start building a second-stage third-generation mobile communication network when all communication networks are based on IP technology, and the Internet connection speed of the third generation mobile network can be up to 2 megons per second, 200 times faster than the current. The fourth-generation technology has the highest speed of up to 100 megons per second. Ericsson has developed 4G technology with the University of California University. California has officially established California Communications and Information Technology Societies, and is divided by the university's San Diego. At present, the Society has received 12 million US dollars in Ericsson, California Communications and Information Technology Association will conduct in-depth research in the fields of 4G technology, advanced antenna systems, new generation mobile Internet, power amplifier technology, and wireless access networks. US HP and Japan NTT Docomo have been teamed up to develop 4G communication technology and products, and the development of the 4G multimedia architecture is expected to provide high-performance multimedia stream content to mobile users, so that media stream data can be better transmitted to mobile phones and other handheld devices. The basic technology research of this architecture is expected to be completed in 2003.
Japan's Docomo Mobile Communications has also conducted research on the fourth generation of mobile communications in Japan, and striving to become the fourth generation mobile communication leader. Docomo plans to launch the fourth-generation mobile communication system in 2006. In 2010, the 4G business is first launched, and it is intended to make it a global standard. The Japanese government decided to allocate 1.2 billion yen from the 2002 financial budget, supporting the "fourth-generation mobile communication system" of the "fourth-generation mobile communication system", making it a global standard. The Japanese government and the main mobile communications enterprises have developed a basic plan for ultra-high-speed mobile communications technology. This 4G mobile communication technology will be formed in 2005. In order to be able to seize the leader of future mobile phone technology, the Japanese Posts and Telecommunications Department has submitted a proposal to develop the fourth-generation (4G) mobile phone specifications to the Japanese Electrical Communications Technology Review. The Japanese Electrical Communication Technology Review will be responsible for reviewing the relevant specifications of 4G technology and determines its frequency, system technology, development schedule. Japan has completed the fourth generation mobile communication system standard proposal after the third generation mobile communication system "IMT-2000", which will be 4G in 2010. 4G raised the rate to 100 mbit / second, the goal of 4G is the realization level before 2010. Japan Electrical Communications Technology Review is estimated that 2001 ~ 2010 Japan 3G market scale will reach 42 megaphilt, only 2010 revenue will reach 930 billion yen, while 4G mobile phone market potential is more than 3G. Japan and South Korea also conduct cooperation in the fourth-generation mobile communications field after IMT-2000, and the two countries will jointly establish an Internet network, such as a wired wireless communication between two countries, and conduct ultra-high-speed satellite communications experiments. The Korean government will spend $ 135 billion, used for the development of 4G communication systems. These funds will be mainly used for high-speed packet transmission technology, fixed wireless communication equipment, and mobile software development and next-generation network processes. In order to promote the research and development process of 4G mobile communication service system, the government set up a research and development team to be responsible for the implementation of the project. The Korean government has established the next generation of mobile communication technology development associations with mobile communication equipment and service companies, and launches 4G and other future mobile communication service technology. The next generation of mobile communication technology development associations will also set up the communication experts of agglomeration, learning, research, and establish a future mobile communication planning committee, responsible for promoting 4G planning, 3G services and system improvements, TDD (Time Division Duplex) scheme for wireless network-specific communications. Research and High Speed Data Communication (High Data Rate). Samsung Electronics's Seri Research Center also started the development of 4G mobile communication technology.
6 Development of my country's fourth generation mobile communication
my country has also achieved great results in the 4G field. The Hanwang "Broadband Wireless IP Communication System" developed by Hanwang Company uses 4G technology and IP network technology, with the core-specific package multiple access technology as the core, and the upper and down data rates are asymmetric. Design, you can provide wireless users with high-speed wireless internet services with nearly 2Mbps, while providing different types of data services such as high-rate text, video, voice, and other data services. The free communication and multicast, multi-point communication, etc. of mobile phones, PDAs, and PCs can be implemented, and it is expected to be used in 2003.
At present, the world's development of countries are actively conducting research and formulation of the fourth-generation mobile communication technology specifications, in order to enjoys a speech in the world's fourth-generation mobile communication specifications. The fourth generation of mobile communication equipment is extremely high, mobile communication is for personal, feedback on the characteristics of good cycle development, and determines its market potential is still very huge. The combination of mobile communications and the Internet will affect the development of mobile communications and the Internet will inject greater vitality. With the high-speed development of the Internet, the fourth-generation mobile communication system will get faster. According to predictions, this broadband, access to the Internet, has a variety of comprehensive functions, the fourth generation mobile communication technology will become mainstream technology for mobile communication market in 2010. In the 21st century, my country's mobile communication has a huge development space, which provides an unprecedented opportunity for my country's mobile communications, and also brings severe challenges. To this end, we need to develop the third-generation mobile communication technology system, and prepare for the introduction of the ITU on the research of the fourth-generation mobile communication standard, master the research trend and the latest results of the world mobile communication technology. Strengthen international cooperation, pay attention, and actively carry out the research and development of the fourth-generation mobile communication technology, combine the development and establishment of the fourth-generation mobile communication and establish China's mobile communication industry, accelerate the development of China's mobile communication industry, so that China's mobile communications Industry has a strong market at home and abroad. Author: Hefei Science and Technology Information Institute ancient Liping Source: Application of Electronic Technique
