What are the characteristics of mobile communication?

Question 1: What are the characteristics of mobile communication? Hello, let me briefly introduce your question about the characteristics of mobile communication.

(1) Expressway. For a large range of high-speed mobile users (250km/h), the data rate is 2 MB/s; For medium-speed mobile users (60km/h), the data rate is 20 MB/s; For low-speed mobile users (indoors or pedestrians), the data rate is100MB/s/s.

(2) Give priority to the development of digital broadband technology. In 4G mobile communication system, millimeter wave is the main transmission frequency band of signals, and the cell will be much smaller accordingly, which will greatly improve the user capacity, but it will also cause a series of technical problems.

(3) Good compatibility. The 4G mobile communication system realizes the global unified standard, so that all users of mobile communication operators can enjoy the same 4G service, and truly realize that a mobile phone can communicate anywhere in the world.

(4) Strong flexibility. The 4G mobile communication system adopts intelligent technology to adaptively allocate resources, which can cope with the ever-changing business traffic and meet the communication requirements. It uses intelligent signal processing technology to send and receive signals normally in complex environments with different channel conditions, and has strong intelligence, adaptability and flexibility.

(5) Multiple users * * *. The 4G mobile communication system can carry out adaptive processing according to the dynamic network and changing channel conditions, so that low-speed and high-speed users and various user equipments can coexist and interoperate, thus meeting the needs of various users of the system.

(6) Integration of various businesses. The 4G mobile communication system supports more abundant mobile services, including high-definition image services, conference TV, virtual reality services and so on. , so that users can get any required information service anywhere. Combine personal communication, information system, broadcasting and entertainment industries into a whole, and provide users with a wider range of services and applications more safely and conveniently.

(7) Application of advanced technology. The 4G mobile communication system is based on many breakthrough technologies, such as OFDM multiple access mode, smart antenna and space-time coding technology, wireless link enhancement technology, software radio technology, high-efficiency modulation and demodulation technology, high-performance transceiver and multi-user detection technology.

(8) Highly self-organizing and adaptive network.

Question 2: What is mobile communication? What are the characteristics of mobile communication? 1. The concept of mobile communication: mobile communication is the communication between mobile bodies or between mobile bodies and fixed bodies. Moving objects can be people, cars, trains, ships, radios and other moving objects.

Second, the characteristics of mobile communication:

1. Mobility: It is to keep the communication of an object in a moving state, so it must be wireless communication, or a combination of wireless communication and wired communication.

2. The propagation conditions of radio waves are complex: because the moving body may move in various environments, electromagnetic waves will produce reflection, refraction, diffraction, Doppler effect and other phenomena in the propagation process, resulting in multipath interference, signal propagation delay and broadening.

3. Serious noise and interference: automobile spark noise, various industrial noises in urban environment, intermodulation interference, adjacent channel interference, co-frequency interference among mobile users, etc.

4. The system and network structure are complex: it is a multi-user communication system and network, and users must not interfere with each other and coordinate their work. In addition, the mobile communication system must be interconnected with local telephone network, satellite communication network and data network, and the whole network structure is very complicated.

5. Need high frequency band utilization and good equipment performance.

Third, the key technologies of mobile communication:

1, power control technology

2. Code technology

3. Rick receiving technology

4. Soft handover technology

5. Speech coding technology

Four, the composition of mobile communication:

(1) space system;

(2) Ground system: ① satellite mobile radio and antenna; (2) Gateway station and base station

Question 3: What is mobile communication? Briefly describe the characteristic concept of mobile communication;

Communication in which one or both parties are in motion. Include land, sea and air mobile communication. The adopted frequency bands cover low frequency, intermediate frequency, high frequency, very high frequency and ultra-high frequency. A mobile communication system consists of a mobile station, a base station and a mobile exchange. In order to communicate with the mobile station, the mobile switching office sends a call to the whole network through each base station, and the called station sends a reply signal after receiving it. After receiving the reply, the mobile switching office assigns a channel to the mobile station and sends a signal from this channel to ring it.

Features:

(1) mobility.

Is to keep the communication of objects in a moving state, so it must be wireless communication, or a combination of wireless communication and wired communication.

(2) The propagation conditions of radio waves are complicated.

. Because the moving body may move in various environments, electromagnetic waves will produce reflection, refraction, diffraction, Doppler effect and other phenomena in the propagation process, resulting in multipath interference, signal propagation delay and broadening.

(3) Serious noise and interference.

Automobile spark noise, all kinds of industrial noise, intermodulation interference between mobile users in urban environment, adjacent frequency interference, same frequency interference.

(4) The system and network structure are complex.

It is a multi-user communication system and network, and users must not interfere with each other and work in harmony. In addition, the mobile communication system must be interconnected with local telephone network, satellite communication network and data network, and the whole network structure is very complicated.

(5) Require high frequency band utilization and good equipment performance.

Baidu Encyclopedia has a very detailed explanation, you can have a look!

Question 4: Characteristics of mobile communication system. This kind of coal quality allows users in communication to move freely within a certain range, and the position is not constrained. However, the propagation characteristics of radio waves are usually influenced by many factors. The operating environment of mobile communication is very complicated. Radio waves will not only be dispersed and consumed with the increase of propagation distance, but also be covered by terrain and objects, resulting in "shadowing effect". Moreover, after multi-point reflection, the signal will reach the receiving place from multiple paths. The amplitude, phase and arrival time of this multipath signal are different, and their superposition will lead to level fading and delay spread. Mobile communication is often carried out in fast motion, which not only causes Doppler frequency shift and random frequency modulation, but also makes the transmission characteristics of radio waves fluctuate rapidly and randomly, which seriously affects the communication quality. Therefore, the mobile communication system should be designed reasonably according to the characteristics of the mobile channel. There are many kinds of mobile communication. It can be divided into: (1) trunking mobile communication, also known as regional mobile communication. Its characteristic is that there is only one base station, the antenna height is tens to hundreds of meters, the coverage radius is 30 kilometers, and the transmitter power can be as high as 200 watts. The number of users is about tens to hundreds, which can be carried by car or held by hand. They can communicate with the base station, or with other mobile stations and local telephone users through the base station, which is connected with the wired network of the local station. (2) Cellular mobile communication, also called cellular based mobile communication. Its characteristic is that the whole large-scale service area is divided into many cells, and each cell is equipped with a base station, which is responsible for the contact and control of each mobile station in the cell. Each base station is connected to each other through the mobile switching center and to the local office. Taking advantage of the limited propagation distance of ultrashort wave, the frequency can be reused within a certain distance from the cell, so that the frequency resources can be fully utilized. Each cell has more than 1 0,000 users, and eventually the capacity of all coverage areas can reach 1 0,000 users. (3) Satellite mobile communication. Mobile communication can also be realized by using satellites to transmit signals. For vehicle-mounted mobile communication, equatorial fixed satellites can be used, while for handheld terminals, multi-constellation satellites with medium and low orbits are more advantageous. (4) cordless phones. For the communication of slow-moving handheld terminals indoors and outdoors, a portable cordless telephone with low power and short communication distance is adopted. They can communicate with local telephone users in one or two directions through communication points. Mobile communication using analog identification signals is called analog mobile communication. In order to solve the problem of increasing capacity, improve communication quality and increase service functions, digital identification signals, namely digital mobile communication, are used. There are two standards: Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). The former includes the GSM system in Europe (Global System for Mobile Communications), the dual-mode standard IS-54 in North America and the JDC standard in Japan. For CDMA, there is an IS-95 standard system developed by Qualnn Company of the United States. The general trend is that digital mobile communication will replace analog mobile communication. Mobile communication will develop to personal communication. Entering 2 1 century, it has become an important part of the global information superhighway. Mobile communication will have a more brilliant future.

Question 5: What are the characteristics of the wireless channel of mobile communication? The wireless channel of 5-minute mobile communication has the characteristics of open propagation, complex receiving environment and random movement of users.

For all-round professional explanation, please refer to the following paper: DOC88/P-207990 195235.

Channel is a metaphor for the path between the sender and the receiver in wireless communication. For radio waves, it is transmitted from the sender to the receiver without physical connection, and its propagation path may be more than one. However, in order to vividly describe the work between the sender and the receiver, we assume that there is an invisible road connection between them and call this connection path a channel. Channels have a certain frequency bandwidth, just like highways have a certain width.

Question 6: What are the characteristics of mobile communication compared with fixed communication? Mobile communication enables you to make phone calls and surf the Internet on the move. Fixed communication is fixed and immovable, at his will. Compared with fixed communication, the advantage of mobile communication is that it can move freely and is not limited by the transmission line of communication terminal, so that you can work and communicate freely. ......

Question 7: Briefly describe the networking unit in the mobile communication network, what are its characteristics and what occasions it is suitable for MS mobile stations, such as mobile phones and other equipment; BSS base station subsystem, including BTS base transceiver station and BSC base station controller; The NSS network subsystem mainly includes MSC mobile switching center (to realize information exchange, system control and connection with fixed telephone network), HLR home location register (a database containing user information), VLR visiting location register (a temporary database containing user information), EIR equipment identification register, AUI authentication center (to realize authentication and encryption of access users) and OMC operation and maintenance center.

Question 8: What is mobile e-commerce and what are its characteristics? Mobile e-commerce is B2B, B2C or C2C e-commerce using mobile phones, PDA, PDA and other wireless terminals. It perfectly combines the Internet, mobile communication technology, short-distance communication technology and other information processing technologies, so that people can conduct various business activities at any time and any place, and realize online and offline shopping transactions, online electronic payment, various trading activities, business activities, financial activities and related comprehensive service activities.

Characteristics of Mobile E-commerce

1, convenient

The mobile terminal is not only a mobile communication tool, but also a mobile POS machine and a mobile bank ATM machine. Users can conduct e-commerce transactions and banking at any time and any place, including payment.

2. Safety

Customers who use mobile banking services can switch to large-capacity SIM cards, use reliable bank keys to encrypt information, and use ciphertext in all transmission processes to ensure safety and reliability.

3, fast and flexible

Users can flexibly choose access and payment methods according to their needs and set personalized information formats.

Development trend of mobile e-commerce

1, enterprise applications will become a hot spot in the field of mobile e-commerce.

Anyone who works in the internet industry has a deep understanding that services and applications for B users (enterprise users) can make money quickly, but generally speaking, the growth will not be particularly large and will not show geometric progression; The services and applications for C users (individual users) are just the opposite. Although you can't make money quickly, as long as the business is done right and lucky, it is possible to make a big business, even a big business.

Similarly, the rapid development of mobile e-commerce must be based on the maturity of enterprise applications. Enterprise application has strong stability and high consumption power, which can't be compared with individual users. Among the business categories of mobile e-commerce, there are many business types that can greatly help enterprise users in terms of income and work efficiency. The rapid development of enterprise applications will become one of the most important forces to promote mobile e-commerce.

2. Obtaining information will become the main application of mobile e-commerce.

The usual practice of Internet companies is that there will be a series of auxiliary applications around the main business, so as to cheat more traffic or bring more opportunities to the main business.

In mobile e-commerce, although the main purpose is transaction, in fact, in the process of business use, the acquisition of information plays a very important role in promoting the occurrence of transactions or indirectly causing transactions. For example, users can use their mobile phones to obtain information about the stock market, weather, travel routes, movies, flights, music, games and other content services through information, e-mail, tag reading, etc., and under the guidance of these information, it will become the initial consideration of major mobile e-commerce service providers.

3. Security will remain an opportunity for mobile e-commerce.

Because mobile e-commerce depends on the wireless communication network with poor security, security is the key factor to be considered in mobile e-commerce. Compared with e-commerce based on PC terminal, the computing power and storage capacity of mobile e-commerce terminal are more insufficient. How to ensure the security of electronic transaction process has become the most concerned issue.

In such a big environment, the formulation of safety standards and the introduction of corresponding laws will also become a trend. At the same time, related suppliers and service providers are also very popular.

4. Opportunities for mobile terminals

Mobile terminals are also a commonplace topic. Information acquisition, transaction and other issues in mobile e-commerce are related to the terminal. The development opportunity of terminals not only lies in driving the new fashion of mobile e-commerce, but also has a vital impact on the smooth cooperation and business development of all parties in the value chain.

With the development of terminal technology, the functions of the terminal are more and more, and the aspects of humanized design are more and more comprehensive. For example, the display screen has made great progress than in the past, and some online transactions involve the display of commodity picture information, which can be closer to the interface display on the traditional PC Internet. Another example is the gradual popularization of smart terminals or becoming mainstream terminals. As a result, the phone was upgraded to a small PC. Although the two will not be completely consistent and will not be replaced, mobile phones can achieve more and more functions, which is more convenient for some mobile e-commerce services without losing the characteristics of portability. In the future, the convergence trend of terminal products will become more and more obvious, and it is difficult for you to clearly define whether this machine in your hand is a mobile phone or an e-book ... >>

Question 9: What is our communication method and what are its characteristics? There are too many ways, such as mobile phones, computers, and writing letters! QQ, Momo, WeChat, a lot. These communications are convenient and fast.