Degree awarding unit: Nanjing University of Science and Technology
Degree level: Master's degree
Year of degree award: 2005
Classification number: E96
DOI: China HowNet: CDMD: 2.2005.118113.
Content: 1 Introduction 8- 13 1. 1 Modern Military Communication Network 8-9 1. 1 Features and Functions of Military Communication Network 81.. ATM technology 9 1 research status at home and abroad 1-121.3.1research status of wireless ATM at home and abroad1.3.2 WATM application in military communication network. 65438+ 438+032 ATM technology and its working principle13-232.63238+06-172.2.4 ATM cell structure AAL17-182.3 ATM/KLOC-0. 2.4./the meaning of logical connection in kloc-0/ATM adaptation layer 202.4.2 establishment and release process of logical connection 20-212.4.3 conversion of VCI and VPI 2 1-222.5 summary 22-233 wireless access technology 23-353./kl Classification of access network technology 202.4 technology 23-243. 1.2 wireless access technology 243 structure and networking mode of wireless LAN 27-283.3.4 development prospect of wireless LAN technology 283.4 local multipoint distribution service LMDS 28-343.4.1IEEE 802.638. 28-303.4.2 Basic Features and System Composition of LMDS 30-323.4.3 LMDS Layer 32-333.4.4 Application of Typical LMDS 33-343.5 Summary 34-354 Wireless ATM Technology 35-484. 1 Concept of Wireless ATM 35-333.30030300006 .2 Comparison between Wireless ATM and Conventional ATM 36-374.2 Wireless ATM Principle 37m Physical Layer (PHY)40-4 14.3.2 Wireless ATM Media Access Control (MAC) Layer 4 1-434.3.3 Wireless ATM Data Link Control (DLC). Layer 434.3.4 Wireless ATM Wireless Control Layer 43-444.4 Wireless ATM Protocol Extensions 44-454.4. 1 Handover Control 444.4.2 Location Management 44-454.5 WATM Network Structure and Protocol Reference Model 45-474.5. 1 Cellular WATM Structure 454.5.0 ATM Network Reference Model 464.5.4 Error Control of WATM Network 46-474.6 Overview 47-485 Application of Switching Mechanism of Tactical Communication System after 2000 50-5 15.2 WATM Technology in Military Communication Network Design 51-605.2./KLOC 25.2.2 Military WATM Protocol Structure 52-545.2.3 Media Access Control MAC and Data Link Control DLC54-565.2.4 Handover Control 56-575.2.5 Location Management and Routing 57-585.2.6 Application of WATM Technology in Military Communication Network Protocol Structure 58-605.3 Performance Analysis of WATM Military Communication Network 38
The two hot spots of communication development are broadband network and wireless communication. ATM is the transmission standard of B-ISDN broadband network based on optical fiber transmission, which is mainly used to provide multimedia services and extensive information access. With the development of mobile communication and the improvement of people's requirements for portability, it is hoped that wired ATM networks can extend their services to wireless mobile terminals, which is the original intention of realizing unlimited ATM.
The realization of wireless ATM can be roughly divided into two stages. The first stage is to realize mobile ATM, that is, to access the mobile terminal to the ATM backbone network by using the existing ATM technology. Its main task is to make the existing ATM network support terminal mobility, expand the concept and various technical indicators of ATM, and make it support call acceptance, routing and call control of mobile terminals. The second stage is to realize wireless ATM, focusing on improving channel quality (increasing transmission rate and reducing bit error rate) and providing high-speed wireless multimedia applications for a large number of users.
[Related Technology] ATM technology; Wireless communication technology; Access network technology [technical difficulties]
Because the transmission media and services of ATM network and wireless communication network are completely different at the beginning of research, some new problems will inevitably be brought when they are merged. For example, when users roam freely, how to choose routes and how to ensure the quality of service (QOS) required by users. In addition, it also puts forward what kind of transmission protocol to choose and how to overcome the problem of poor transmission quality in wireless channels. The following will introduce several technical difficulties:
User mobility and handover
The existing ATM protocol does not support the mobility of users, and the virtual connection it establishes lasts until the end of the user call. However, when users require handover in the communication process, the problem of user routing demand adjustment is particularly obvious. There are some handover strategies, but the bandwidth of wireless channel is extremely limited. How to allocate channels to ensure that the call loss of users is very small is also an extremely important problem in wireless ATM.
2. The disorder of 2.ATM cells.
In wireless ATM, users may change their routes while moving, so confusion may occur.
3. Wireless access problem
The existing ATM has been completely or partially replaced by wireless logical link control layer and media access control layer. Because the existing ATM technology is based on low bit error rate and high bandwidth transmission channel, and the bit error rate of wireless channel is very high, it is much more difficult to transmit user data on wireless channel than on wired link while ensuring service quality.
4. Quality of service required by users
Service quality is one of the main advantages of ATM. Because of the characteristics of wireless channel (high bit error rate, limited bandwidth, time-varying physical characteristics, etc. ) is very different from wired channels, and some of them are even completely contrary to the assumption based on ATM. Obviously, the definition of quality of service in existing ATM protocols is not necessarily applicable to wireless environment.
In a word, many problems brought by wireless communication environment will be the difficulty to realize wireless ATM. At present, many foreign scientific research institutions have invested huge manpower and material resources in research, and some experimental networks have been opened one after another. Over time, these problems will be solved.
[Overview of Foreign Countries] Modern communication is developing rapidly in two different directions. One is the growing global broadband communication; The other is wireless communication based on cellular structure. They are mainly used to transmit voice services and low-rate data services. ATM technology is an internationally recognized target mode to realize broadband network. One of its main advantages is to ensure the quality of service (QOS) and the connection-oriented characteristics of the service, and it can flexibly support various existing and future possible services, laying the foundation for realizing broadband real-time multimedia services. Especially with the opening of some commercial ATM networks, people are more and more interested in broadband multimedia communication. With the opening of the Internet, people's demand for multimedia communication is increasingly urgent. In addition, in recent years, the mobile communication industry has also developed at an amazing speed, mainly because it has freed people from the shackles of traditional communication methods, enabled people to move freely in the communication process, and greatly facilitated users, thus making wireless communication, especially cellular mobile communication, a major force in the world telecommunications market in the past two or ten years. With the development of satellite communication and the wide use of portable computers, people are more and more interested in mobile data communication.
At present, broadband communication and mobile communication are still developing in their respective directions, but the importance of portable computers and mobile communication is becoming more and more obvious, which also urges the introduction of wireless access technology into ATM networks to realize the combination of wireless communication networks and ATM networks. Therefore, wireless ATM technology appeared.
At present, wireless ATM, as a new technology, has become the focus of communication field. 1In June, 1996, ATM Forum established a wireless ATM working group, which was responsible for the standardization and system planning of wireless ATM. At the same time, many international scientific research institutions and colleges have also organized a lot of manpower and financial resources to conduct research step by step from different angles according to various plans. Although the development of wireless ATM is still in the experimental stage, it has become a new focus in the field of communication. Here is a brief introduction to the research on wireless ATM in various countries around the world.
At&T Company. T's Bell Laboratories put forward BAHAMA scheme, that is, broadband private wireless ATM LAN. The component of the network is called the mobile base station, and the encapsulation and unpacking of ATM are all carried out in the mobile unit. In order to support mobility in this simplest way, new concepts of virtual channel identifier and virtual call identifier are defined to support the routing of destination addresses. Recently, Bell Laboratories and Sun Company jointly proposed a new BAHAMA scheme called Mobile Information Infrastructure (MII), which was supported by the National Institute of Standards and Technology.
The "Wireless ATMnet" system described by NEC C & ampC Research Laboratory in Princeton, USA is an ATM network of personal communication network. It is suggested that ATM cell delay technology be used as the basis of the next generation wireless transmission structure. Wireless ATM protocol stack includes wireless data link layer and multiple access layer, and the handover function is completed in data link layer.
Acampora and Naghshineh of Columbia University put forward a virtual tree structure to deal with the topology problems in wireless cellular access networks using ATM transmission technology, which supports high-speed handover between cells.
In addition, Purdue University's Internet wireless campus network based on ATM switch has passed the test and achieved initial success.
The Communication Research Association of Canada sponsored a research project: 160Mbps wireless high-speed access system in the range of 20-60GHz, which was co-operated by three research institutes and seven universities. They developed cutting-edge millimeter wave technology and surface acoustic wave technology, and realized a honeycomb structure with a cell radius of about 30-50 meters. In 1996, an experimental system running at 40Mbps is studied.
In 1994, Olivetti Laboratory in Cambridge established an experimental wireless ATM LAN, which runs at 10Mbps, and uses 2.45GHz wireless QPSK to exchange with the low-end ATM running at 100Mbps. It has a picocellular structure and cannot be reused in frequency. The radius of the picocell is about 10 meter. The multiple access layer adopts exponential concession slotted ALOHA technology, which is realized by Xilinx programmable gate array.
The European Union is also supporting the research of wireless ATM. There are two specific schemes for wireless ATM in subscriber premises network. They are magic wand and He Dian wireless broadband CPN/LAN plan, which are used for professional residential multimedia applications. The purpose of these two plans is to extend ATM to mobile terminals. The goal of MagicWAND is to develop a wireless interface with a rate of about 20Mbps in 17GHz band. He Dian is a wireless interface of 60GHz band 155Mbps. Germany, Switzerland, Sweden and Italy have also invested heavily in developing wireless ATM technology.
The joint project of Swedish enterprises and universities led by Swedish Federal Institute of Technology is also an experimental system to realize wireless ATM.
The ATM Wireless Access (AWA) of NTT Wireless System Laboratory in Japan mainly studies UHF ATM networks in private local area networks, wide area networks and public environments. In addition, Singapore, Malaysia and other countries have also invested a lot of manpower and material resources to study ATM technology.
In a word, the research of wireless ATM has been started for some time, but the most important part of the standard has not been done yet. The main goal of commercial companies is to adopt systems that meet standards. 1995 June 5438+00 is the biggest milestone of wireless ATM. At that time, the main body of wireless ATM was submitted to two different standardization forums, namely ETSIRES 10 and ATM forum.
Generally speaking, there are two schemes to realize wireless ATM: one is to apply TCP/IP protocol superimposed on wireless ATM layer to provide comprehensive Internet services; The second is to introduce wireless ATM interface, so that wireless users can access ATM network like wired users.
The above research on wireless ATMs all over the world has clearly shown that with the popularization of portable computers and the improvement of their performance, the application of local area networks and the increasing demand for ATMs to families, the application of wireless ATMs will become possible. The above technical scheme of wireless ATM can be used as the development basis of wireless ATM from research and development stage to productization and standardization. Broadband wireless technologies such as wireless ATM are of great help to the multimedia application of the network. There is still a lot of work to be done in the design and optimization of wireless ATM, VLSI, software development of key systems, high-speed modem and media access control of specific wireless access layer, handover control protocol of mobile ATM network and so on. In the process of building a wireless ATM system. The wireless ATM protocol layer contains more optimization and conversion schemes. At present, famous large companies in the world and research institutions in various countries are carrying out similar designs. At the ATM forum, the wireless ATM working group is going all out to promote its standardization work. Undoubtedly, wireless ATM plays an inestimable role in realizing the information superhighway.
[Impact] From the perspective of development, wireless ATM technology will play a decisive role in the development of national economy and national defense technology and weapons and equipment, and the future is immeasurable.
In commercial and public markets, the increasing importance of mobile computing and mobile communication has greatly promoted the development of ATM technology and other wireless network technologies. In recent years, the rapid popularization of mobile phones and notebook computers shows that it is very important to closely integrate mobile technology with people's lives. In the past few years, the first generation of multimedia technology has been used in notebook computers, reflecting the increasingly important role of multimedia in computer applications. Driven by the market, wireless ATM technology, which combines the broadband, multimedia and adaptability of ATM technology with the mobility and flexibility of mobile communication, will surely play a huge role in the national economy.
Wireless ATM will also play an extremely important role in military communication, especially today when military communication emphasizes mobility and flexibility. Take the United States as an example With the end of the Cold War, there is little possibility of another world war, and regional wars will become the main form of future wars. Therefore, the military strategy of the United States has changed from the pre-positioning strategy in the past to the flexible and deployable Joint Task Force (JTF). The military communication planning of the United States has also changed. In the future, the global communication network of the US military will be the Defense Information System Network (DISN), which consists of three parts: long-distance trunk lines, bases and deployments. In local wars, JTF will use deployable parts to complete its internal communication (army battlefield information transmission system-BITS, Navy Copernicus system, Air Force Horizon system, Marine Corps Hailong system) and connect to the United States through long-distance trunk lines. DISN takes a fancy to the characteristics of wireless ATM, which integrates broadband multimedia communication and mobile communication, and regards it as the main communication form for future deployment.
To sum up, whether in the national economy or in the development of national defense technology and weapons and equipment, wireless ATM will have a bright future.
References:
1, Meng Jinquan, Research on Wireless ATM Technology, Digital Communication, 1997(3), pp. 35-36, 43.
2. Xue Yonghui et al., "Research and Development Background of Wireless ATM Technology Abroad", Communication World, 1998(2), pp. 52-54.
3, translated by Xue Yonghui, The Future of Wireless ATM, Modern Telecommunication Technology, 1997(6), pp. 28-30, 49.
4. Song,, et al., "Wireless ATM Network-Architecture, System Design and Experiment", Foreign Military Telecommunications Dynamics, 1997(4), p. 17-24 24.
5. Li Jingfeng et al., "Introduction to Wireless ATM Technology", ZTE New Communication, 1997(5), pp. 40-43.
6. Cheng Shiduan, etc. Asynchronous transmission mode, People's Posts and Telecommunications Publishing House said ... 8 The perspective of studying ATM communication in the same field is also 8. ..............................................................................................................................