4G communication technology is based on the previous 2G and 3G communication technologies, in which some new technologies are added.The wireless communication signal is more stable, the data transmission rate is improved, and the compatibility is smoother,The quality of communication is also higher. Moreover, the technology used in 4G communication is more advanced than 2G and 3G communication, which makes the speed of information communication faster.From the point of view of technical standards, according to the definition of the International Telecommunication Union (ITU), the static transmission rate of 4G reaches 1 Gbps.It can reach 100Mbps in high-speed mobile state.4G communication technology is based on the continuous optimization, upgrading, innovation and development of 3G communication technology, which integrates the advantages of 3G communication technology.And derived a series of its own inherent characteristics, with WLAN technology as the focus of development.The innovation of 4G communication technology makes it have a greater competitive advantage compared with 3G communication technology.Firstly, 4G communication can realize high-definition transmission of original pictures and videos in picture and video transmission.Its transmission quality is comparable to computer picture quality. Secondly, using 4G communication technology,It can download software, files, pictures, audio and video at a maximum speed of tens of megabits per second.This can not be achieved by 3G communication technology, and it is also a significant advantage of 4G communication technology.This fast download mode can bring better communication experience and facilitate the download of learning materials in daily learning. At the same time,Under the background of high-speed and convenient development of the network, users also put forward higher requirements for the cost of traffic.Judging from the current 4G network communication charges, the price is relatively high.However, major operators have also introduced corresponding traffic preferential policies for different groups, which can meet the needs of different consumer groups.

Key technologies

OFDM technology

FSK has a little anti-interference, and the code is a unipolar non-return-to-zero code. When the code sent by the sender is 1,It means it is in high frequency. When the transmitted code is 0, it means it is in low frequency.If the transmitted code is 1011010, the waveform formed by the code will show periodic fluctuation.The signal transmitted by the OFDM technology has a certain overlapping part, and the technical personnel can analyze the signal according to the processor,According to the slight difference of frequency, different information categories are divided, so as to ensure the stable transmission of digital signals.

MIMO technology

MIMO uses mapping technology. First, the sending device sends information to the wireless carrier antenna. After the antenna receives the information,It will compile it quickly and compile the compiled data into digital signals, which will be sent to different mapping areas.Then, the received data signals are fused by using the diversity and multiplexing modes to obtain the hierarchical gain.

Smart antenna technology

Smart antenna technology is an effective integration of time division multiplexing and wavelength division multiplexing technology. In 4G communication technology,Smart antennas can achieve omni-directional coverage of transmitted signals, and the coverage angle of each antenna is 120 degrees.The transmitting base station will be equipped with at least three antennas.In addition, smart antenna technology can adjust the transmission signal to obtain gain effect and increase the transmission power of the signal.It should be noted that the gain control here is not related to the radiation angle of the antenna.It only increases the transmission power on the original basis.

SDR technology

Software radio technology is one of the common technologies in radio communication technology.The technical idea is that a broadband analog-to-digital converter or a digital-to-analog converter is sufficiently close to a radio frequency antenna,Write specific program code to complete frequency band selection, sample and transmit information for quantitative analysis.The differential selection of the channel modulation mode can be realized, and the selection of different security structures and control terminals can be completed.

Related network architecture

EPON network architecture

The EPON networking structure is composed of three parts.There are terminal equipment, switching equipment and power grid central office equipment between the user and the communication provider.There are 64 transmission frames in the transmission line, and each transmission frame includes 24 bytes, that is, 192 bits of data.The maximum transmission distance of this transmission structure can reach 20 kilometers.The EPON transmission line is divided into upper and lower layers, and the upper layer is transmitted by time division multiplexing.The switching device will transmit different information to the terminal device at different transmission times to avoid confusion of various information;The lower line is transmitted in real time by broadcasting, and the terminal equipment discriminates different information.Select the information needed in real time to receive. 

TD-LTE network architecture

TD-LTE mainly plans the distribution of network information from three levels, in which the core layer is to improve the speed of data transmission.The transmission time from the user terminal to the base station is reduced; The service layer is to complete the processing and exchange of data. In the 4G communication service,There is a lot of data information to be transmitted, and the service layer can effectively improve the original transmission rate and alleviate the delay of receiving data.The transport layer is mainly used to access the passive optical network to realize light splitting between the OLT and the NOU.The ONU shall adopt dual PON transmission mode at the uplink port to form a protection network near the central office equipment to avoid data loss.

Advantage

Significantly improve communication speed

Compared with the previous 3G communication technology, the biggest advantage of 4G communication technology is that it significantly improves the communication speed.It enables users to have a better experience, and at the same time promotes the development of communication technology in China.The development of communication technology is a long process. In the first generation of mobile information system, there is only voice system.When the second generation mobile information system is developed, the communication speed is only 10kb/s, and when the 3G communication technology stage is developed,There is no qualitative leap in speed, only a simple 2Mb/s. All these have become factors hindering the development of China's telecommunications industry.However, the emergence of 4G communication technology has obviously made a qualitative leap in terms of communication speed.This not only reflects the rapid development of China's telecommunications industry,We can also see the continuous progress of our society and the rapid development of network technology.It reflects the continuous improvement of China's economic strength, and also shows that China's comprehensive strength is constantly improving.

Communication technology is more intelligent

Compared with the previous mobile information system, 4G communication technology has realized intelligent operation to a large extent.This is more in line with our current needs. The mobile phone we use in our daily life is a good manifestation of the intelligence of 4G communication technology.Intelligent 4G communication technology can respond more accurately according to different instructions in the process of people's use.The searched data is analyzed, processed and collated, and then transmitted to the user's mobile phone.4G mobile phone, as a communication tool that people can not do without, greatly facilitates people's lives.

Improve compatibility

The degree of cooperation between hardware and software is what we usually call compatibility.If the conflict between hardware and software is reduced, the compatibility will be improved, and if there are more conflicts, the compatibility will be reduced.The emergence of 4G communication technology has improved the performance of compatibility and reduced the conflict between hardware and software in the working process.It makes the cooperation between hardware and software more tacit, which also avoids the occurrence of failures to a large extent.One of the ways that 4G communication technology has improved compatibility to a great extent is that we seldom encounter the stuttering and flashback that we used to see before.And so on many kinds of breakdown, lets the people use the communication equipment in the process to be more smooth and fluent.

4G network security issues

Security of Network Information

Although 4G communication technology has brought great convenience to people's lives,However, the network security issues directly affect the security of user information.Among them, there are some illegal elements who fake operators and carry out telecommunication fraud against communication users.Or make some links or short messages with viruses, and once the communication user opens these links or short messages,Illegal elements will directly steal users'telephone charges or bank card information through network services.There are also some hackers with relatively high computer expertise, who can use computer technology to steal users' accounts and information.And can pass the identity authentication, directly into the network, which poses a threat to the information security of communication users.In addition, the number of connected clients of 4G broadband network is limited, which also makes it easy for criminals to monitor the client of users.User information can also be modified, making the network connection less secure.

Security Issues in Mobile Terminals

With the continuous development and innovation of 4G technology, mobile terminals are the key elements of communication between people.Mobile terminals are also constantly updated, and their forms are becoming more and more diversified. Traditional mobile terminals can only make and receive calls.Nowadays, mobile terminals can not only make and receive calls, send and receive short messages, but also realize video calls.With the expansion of the functions of mobile terminals, the security technology is also constantly innovating.With the continuous development of 4G communication technology, more and more people use smart phones, so the number of mobile terminal users is increasing.The relationship between users is becoming closer and closer, and the requirements of users for the storage function of mobile terminals are becoming more and more stringent.This requires relevant enterprises to continuously upgrade the cloud storage space of mobile terminals.However, upgrading cloud storage will also have certain risks, such as making the terminal unable to effectively resist the invasion of viruses.Therefore, more and more telecommunication fraud problems come one after another.

Security Issues in Authentication Systems

With the continuous development and innovation of 4G communication technology, various illegal elements have found loopholes in its technology.Directly or indirectly endanger the user's information security and property security, then the authentication system is particularly important.However, the authentication system has not been the focus of attention of the majority of users, resulting in a variety of bad information in the network.The network health that affects a user investigates the prime cause that its happen, basically have the following: the first, user amount shows growth trend.The number is getting larger and larger, which has caused a lot of pressure on real-name authentication and made the work of real-name authentication more complicated.In addition, the authentication time is long, and users will lose patience in the waiting process.Secondly, the development of computer network technology is faster and faster, and the real-name authentication technology also needs to keep up with the development of network technology.The difficulty also increases.Thirdly, there are many types of wireless networks, and there is no unified and fixed network mode, which makes it difficult to continue the authentication work.

Solution to 4G network security countermeasures

Improve the security of network information

In order to effectively improve the security of 4G communication technology, we must first have a network technology with high security.To ensure the safety of users and information security, so as to avoid the invasion of some illegal elements.Secondly, it can update the password system, the traditional password setting is relatively simple, and it is easy to be cracked.It uses advanced password technology to make passwords more complex, and also adds SMS verification, fingerprint verification and so on.Let some network hackers have no way to start, and ultimately ensure the user's communication security and Internet security.In addition, we should also publicize network security education to users and improve their information security vigilance.Only by improving people's security awareness, can we better ensure the security of network communication technology.To ensure the safety of users' property and information.

Improve the security of the mobile terminal

The security of mobile terminals directly affects the information security and communication security of users.Therefore, it is necessary to improve the security of the mobile terminal and improve the system of the mobile terminal.First of all, it is necessary to improve the operating system in 4G communication and adopt a more scientific access mechanism to achieve remote control.Strictly manage the mobile terminals of users, and establish a security protection mechanism for the mobile terminals of each user.Ensure the security of information communication.Secondly, improve the cloud storage function of mobile terminals, so that they are not affected by external factors, and block the invasion of viruses.Finally, the system of the mobile terminal is improved, and the access of security data is done well.After strict supervision, the data in the mobile terminal can flow into the user's terminal to reduce the release of bad information.

Improve the security of the authentication system

Improving the security of authentication system is also an important way to effectively solve the network security problems of 4G communication technology.Although most of the 4G communication networks used by users have passed the authentication system,However, there are still many universal key software in the mobile phone application market that can crack the network password.This shows that a single password authentication system can not completely ensure the security of the network, and the authentication system in our country is too simple.At this time, high-end cryptographic technology and means are needed to update the authentication system, for different network communication technologies.It is necessary to update and improve pertinently, establish a scientific authentication mechanism, and greatly improve the security of the authentication system.

Application

Mobile phone online games

Mobile online games are one of the important supporting industries in China's economic composition.In the operation of mobile online games, 4G communication technology is applied.The rapid development of mobile online games is due to the development of 4G communication technology, which makes people feel better in the game process.It is more smooth and fluent, and the high-speed 4G communication technology also meets the needs of people to start games anytime and anywhere.This shows that 4G communication technology provides a certain opportunity for the development of mobile online games.

Cloud Computing and Live Video

Cloud computing is a field that our country is focusing on at present, which is of great significance to the progress and development of our country.Because of the huge amount of information in computing, cloud computing has put forward better requirements, before the development of 4G communication technology.This work will waste a lot of manpower, material and financial resources.However, the emergence of 4G communication technology has made up for this deficiency and greatly improved the efficiency of cloud computing.Video live broadcasting is also the same as mobile phone online games, which has set off a great craze at present.However, live video broadcasting also needs strong communication technology as support.With the use of 4G communication technology, live video broadcasting becomes more convenient and smooth.

Defect

Technology is difficult

Although the 4G network can bring a lot of convenience to people's life and work,However, in practical applications, there are still a series of technical problems to achieve the download speed of 4G network.For example, how to ensure that when workers are in high-rise buildings, mountainous areas, and other vulnerable areas with obstacles,The signal strength and network transmission speed of mobile office will not be affected by it. In addition, there are technical problems between regional changes.When the mobile office equipment you use moves from the coverage area of one base station to the coverage area of another base station,It is easy to lose contact with the network in the region, resulting in network interruption and affecting office efficiency.

Facilities are slow to update

Before that advent of the fourth generation mobile communication system,Most of the wireless infrastructure in the world is based on the third generation mobile communication system.If we want to cover a large area of 4G communication network and realize technology transfer,Many wireless infrastructures around the world will face a lot of innovation.This innovation is bound to slow down the speed of 4G communication network entering the market and occupying the market.At the same time, it is also necessary to ensure that the 3G terminal has been upgraded to a 4G terminal capable of higher speed transmission and supporting various data services of the 4G network.That is to say, 4G terminals should be able to provide services in time after the completion of the 4G network, and the production of communication terminals should not lag behind the network construction.

Inherent disadvantages

Because for individuals, the 4G internal network and the general 4G network are basically the same in use.So its disadvantage is the same as the general 4G network, they all need a special external wireless network card to link to the 4G network.Therefore, it also has the defects of inconvenient carrying of the network card and easy damage to the equipment.And because the network cable network card needs to use a USB interface when being connected with a computer,For notebook computers with only three USB interfaces, the use of wireless network cards requires the choice of other external devices.

Development prospect from 4G to 5G

On the whole, most of the business data provided by 4G network is all-IP network.Therefore, to a certain extent, it can meet the development needs of mobile communication services.However, with the rapid development of economic society and Internet of Things technology,Cloud computing, social networking, car networking and other new mobile communication services continue to emerge, which puts forward a higher level of demand for communication technology.In the future, the mobile communication network will completely cover our office, entertainment and rest areas and residential areas.And each scenario has completely different requirements for the communication network.For example, some scenarios require high mobility, some scenarios require high traffic density, and so on.However, for these needs, the 4G network is difficult to meet, so in view of the new needs of future users.We should focus on exploring higher speed and more advanced mobile network communication technology.[7] The fourth generation mobile communication technology has high bandwidth, so it presents high-definition pictures and videos to meet people's needs.5G is born for the Internet of Things.Compared with other network technologies, 5G communication network has larger capacity and ensures faster Internet access.Generally, intelligent terminals are connected to Internet devices for network transmission.5G technology provides a larger network platform for the Internet of Things, thus meeting greater operational needs.4G network can provide certain services to intelligent users, but it can not be optimized in time according to the changes and needs of the Internet of Things.The terminal equipment supported by 5G communication network is several times more than that supported by 4G communication network, while ensuring lower energy consumption.The 5G communication network solves the problem that the game cannot be played continuously in real time using the 4G network.As a communication network system with efficient connection and low energy consumption, 5G communication network is constantly changing under the premise of Internet technology.The network, business and control have changed to some extent, which has led to changes in the service objects of related industries.

In the third quarter of 2021, the number of 4G users in the world increased by 48 million.

4G slowdown is questioned

With the large-scale construction of 5G, many users have questioned that the 4G network is slowing down. In 2019, there was a rumor of 4G slowdown.At that time, the three major operators said that they had never received any request to limit the speed of 4G, nor had they ever limited the speed of 4G for users.Wen Ku, director of the Information and Communication Development Department of the Ministry of Industry and Information Technology, said that the Ministry of Industry and Information Technology has set up a monitoring platform covering the whole country.Monitor the speed of 4G network through technical means.Monitoring shows that in recent years, the average download rate of 4G in China has continued to increase, and there has been no significant decline in the overall rate.However, he also admitted that the 4G network is a shared network, which is shared by all users in the region, and the speed will fluctuate within the range.The speed of network experience will also be affected by many factors, including the number of users, the scale of traffic, the number of website visits and so on.For example, in railway stations, concert sites and other user-intensive places, it may cause a temporary decline in the rate of experience.According to an analyst in the telecommunications industry, operators have invested a large amount of money in the construction of 5G with limited financial resources.This has led to a decline in investment and operating costs in the 4G network.As 4G users still far exceed 5G users, this will inevitably increase the pressure on the existing 4G network.Reduce the user experience on the 4G network.Another trend is that with the large-scale development of 5G construction, operators are gradually withdrawing 2G or even 3G networks.In order to free up spectrum resources and reduce operation and maintenance costs. In the process of withdrawing 2G and 3G networks, users should be guided to transfer to 4G.This further increases the number of users and traffic scale of the 4G network.