What is 5G? Key technologies of 5G
Mobile communication development history
In the field of mobile communications, the terms "3G" and "4G" are often heard. "G" is the abbreviation of "Generation". Each "G" represents a development stage and an era of mobile communications. Mobile communication technology started from its birth in the 1980s, after more than 30 years of development, it goes through a development stage approximately every 10 years. Let me introduce the development history of mobile communication from "1G" to "5G".
The first generation mobile communication system (1G)
The first generation of mobile communication technology was born in Bell Labs in the United States. In 1978, the American Bell Experiment successfully developed the Advanced Mobile Phone Access (AMPS, Advanced Mobile Phone Access) and built a cellular mobile communication system. The concept of cellular network was also first proposed by Bell Labs and is still in use today. The first generation of mobile communications mainly uses analog technology and frequency division multiple access (FDMA) technology. The principle is relatively simple. It modulates/demodulates the analog signal and then transmits it through the allocated radio frequency resources. The technology leader in the 1G era is Motorola in the United States. His wireless communications representative product is what people commonly call "Big Brother." In the era of 1G analog communications, Motorola has an absolute dominance, accounting for as much as 70% of the global market share, and has a number of wireless communication technology patents. The first generation of mobile communications mainly represents systems, including AMPS, NMT, TACS, etc. What China mainly adopts is TACS (TotalAccess Communications System, improved total access communication system). China's first-generation mobile communication system was officially opened and commercialized at the Sixth National Games of Guangdong on November 18, 1987. This also represents the arrival of the "1G" era in China's mobile communications industry. The first-generation mobile communication system using analog signal transmission has many defects, such as poor call quality, unstable signals, and easy eavesdropping. Without international standards, international roaming cannot be achieved.
The second generation mobile communication system (2G)
The leader of 2G technology belongs to Europe. In 1982, the European Commission for Posts and Telecommunications proposed the GSM (Global System for Mobile Communications) standard. After 1990, GSM became the second-generation mobile communication standard in Europe and the world. GSM uses time division multiple access (TDMA) to transmit data, which has the characteristics of standardization and open interfaces. GSM is a milestone in the mobile communication system. At its peak, it occupies 85% of the world's market share and is a veritable overlord in the 2G era. The GSM data transmission rate is 9.6 kbit/s in the uplink and 14.4 kbit/s in the downlink. IS-95 IS-95 is a digital cellular communication standard in North America. It uses code division multiple access (CDMA) to transmit data. It has the advantages of large capacity and good voice quality. However, due to the low degree of standardization, the market scale is far inferior to the GSM system. There is also a transitional version in the 2G era-2.5G. In order to achieve greater data transmission capabilities, since 1996, GPRS, EDGE, and IS-95B (later evolved into CDMA1X) and other upgrade technologies have emerged, which are called 2.5G. 2.5G technology is a powerful supplement to the 2G era. The GPRS data transmission rate is up to 9.6kbit/s and down to 116kbit/s; the EDGE data transmission rate is both up and down 384Kbit/s, which effectively served as some multimedia applications at that time. Demands extend the life cycle of the GSM system.
The third generation mobile communication system (3G)
With the advent of the 3G era, mobile communications have begun to move from narrowband to broadband. The 3G system is different from previous systems. It is the first international standard issued by the ITU (International Telecommunication Union). It can transmit voice, data, graphics, video and other multimedia applications at the same time. The uplink data transmission rate is 5.76 Mbit/s, and the downlink data transmission rate can reach 7.2 Mbit/s. There are three standards for 3G systems, namely CDMA2000, WCDMA, and TD-SCDMA. The full name of WCDMA is Wideband CDMA, which is developed from GSM and also a broadband CDMA technology proposed by Europe, which can be smoothly upgraded on the existing GSM network. Therefore, it has become the most widely used 3G standard in the world, and once occupied 80% of the global 3G system market share. CDMA2000, also known as CDMA1X, was proposed by Qualcomm North America. This system has a low construction cost. However, only a few countries and regions such as Japan, North America, and South Korea use CDMA, so global applications are not widespread. TD-SCDMA is a 3G standard proposed by China. It was proposed to ITU by Datang Telecom (formerly the Institute of Telecommunications Science and Technology of the Ministry of Posts and Telecommunications) on June 29, 1999. It has the characteristics of low radiation, and has advantages in spectrum utilization and frequency flexibility. It has advantages in terms of cost and cost. Since the beginning of 3G, China has occupied a place in the world of mobile communication technology.
The fourth generation mobile communication system (4G)
4G is the mobile communication technology currently in use. In the 4G era, there are two 4G standards recognized by the ITU: LTE-Advanced and Wireless MAN-Advanced. On January 18, 2012, the ITU (International Telecommunication Union) formally reviewed and approved the establishment of LTE-Advanced and Wireless MAN-Advanced as 4G international standards at the 2012 Radiocommunication Assembly Plenary Session. TD-LTE-Advanced formulated by China has become the 4G international standard. Later, it was unified with the FDD-LTE-Advanced standard into LTE-Advanced. Using LTE-Advanced 4G technology, the peak rate can reach 500Mbit/s in the uplink and 1Gbit/s in the downlink, which strongly supports large bandwidth applications. The high-speed transmission of 4G has spawned the explosive growth of mobile applications such as live broadcast and short video. Mobile applications have become more colorful. High-definition video, smart home, and the Internet of Things are increasingly entering the lives of the people.
The fifth generation mobile communication system (5G)
In the development process from 1G to 4G, the upgrade of technology is mainly reflected in the improvement of speed, and the improvement of indicators such as stability and security. So what changes will 5G bring to us? There is a point of view at the moment-"4G changes life, 5G changes society". The biggest change in 5G is to move from communication between people to communication between people and things, to realize the interconnection of all things, and to promote social development.
The meaning of 5G is not only on mobile phones, the Internet of Everything is not just a slogan, artificial intelligence, unmanned driving and other aspects are inseparable from 5G high-speed connections. Without 5G, the development of other related industries will also be restricted and lag behind others. This is also the main reason why countries attach importance to 5G and compete for 5G voice.
5G application scenarios
The 5G future mobile applications defined by the ITU in June 2015 include the following three areas:
Enhanced Mobile Broadband (eMBB): Human communication is a basic requirement that mobile communication needs to meet first. EMBB future will continue to enhance the human visual experience through higher bandwidth and shorter delay;
large-scale machine-type communication (mMTC): for vertical industries all interconnected, IoT industry has developed rapidly, the future will be the
current number of mobile Communication sensor network has high requirements for the number of connections and energy efficiency; High reliability and low latency communication (uRLLC): for special vertical industries, such as industrial automation, telemedicine, smart grid, etc., which require high reliability + low latency Business needs.
Key 5G technologies
- Ultra-Dense Networking (UDN)
Ultra-dense network needs to be composed of a large number of small base stations. Small base stations are low-power wireless access points that work in authorized steps. The coverage range is generally 10m~200m. In contrast, Acer The coverage of the station can reach several kilometers. Common small base stations can be further subdivided into femto base stations, pico base stations, and micro base stations.
2. Massive MIMO technology.
Traditional MIMO technology has been widely used in 4G networks. As the 5G mobile communication system requires much higher transmission rate than the existing 4G communication system, the traditional MIMO technology can no longer meet the performance requirements of the 5G system. Massive MIMO technology emerged at the historic moment, providing a brand-new solution for 5G high-rate transmission. It is equipped with a large number of antennas at both ends of the transceiver, thereby serving dozens of users at the same time and frequency resource block. - Dynamic self-organizing network (SON)
dynamic self-organizing network is used to meet the performance requirements of 5G: low latency and high reliability scenarios to reduce end-to-end latency and improve transmission reliability; in low power consumption and large connection scenarios Extend network coverage and access capabilities. Under the traditional cellular network architecture, the terminal must pass through the base station and the cellular network gateway to communicate with the target terminal. Under this architecture, the terminal must first select a serving base station before obtaining data transmission services, and establish and maintain a connection with the serving base station.
In a dynamic ad hoc network, any access network node has the function of data storage and forwarding. Each node in the dynamic ad hoc network has the ability to send and receive wireless signals, and each node can communicate with the previous one or more Two adjacent nodes communicate wirelessly, and the entire ad hoc network is in a mesh structure. In a dynamic self-organizing network, any node (terminal and terminal, terminal and base station, base station and base station, etc.) communicates wirelessly without any wiring, and has a redundancy mechanism and rerouting function to support distributed networks. Any new node (such as a terminal or a base station) is added by simply connecting the power source, the node can be automatically configured, and the best multi-hop transmission path is determined.
The dynamic ad hoc network has the following advantages:
Flexible deployment, support for multi-hop, high reliability, and support ultra-high bandwidth
4.
The core idea of software-defined networking (SDN) is to separate the data plane and control plane of traditional network equipment, so that Users can uniformly manage and configure various network forwarding devices through standardized interfaces. Continuing to provide network programming interfaces for upper-layer applications, and providing management of actual physical network elements.
5
The core idea of network function virtualization (NFV) is to decouple software and hardware, realize telecom network functions based on general computing, storage, and network equipment, improve management and maintenance efficiency, and enhance system flexibility. Traditional dedicated hardware networks and communication equipment will gradually be virtualized and softwareized, with more flexible deployment and lower management and maintenance costs.