Wireless communication technology-cellular mobile network
Cellular mobile network services, Baitong's popular understanding is mobile phone services, including calls, traffic and other services.
1. Introduction:
Cellular network or cellular network (Cellular network) is a kind of mobile communication hardware architecture, which divides the service of mobile phones into small sub-areas of regular hexagons, each cell is provided with a base station, forming a shape similar to The "cellular" structure, so this mobile communication method is called cellular mobile communication. Cellular network can be divided into analog cellular network and digital cellular network, which is mainly different from the way of transmitting information.
2. Composition: The
cellular network consists of the following three parts: mobile station, base station channel subsystem, and network subsystem. A mobile station is a network terminal device, such as a mobile phone or some cellular industrial control equipment. The base station subsystem includes mobile base stations (large iron towers), wireless transceiver equipment, dedicated network (usually optical fiber), wireless digital equipment, etc. The base station subsystem can be regarded as a converter between the wireless network and the wired network.
①1G:
Analog communication system, the main standards are AMPS, NMT, TACS. The first generation of mobile communication technology uses multiple cellular base stations, allowing users to move freely during a call and seamlessly transmit calls between adjacent base stations.
② 2G:
Digital network. The second generation mobile communication technology is different from the previous generation. It uses digital transmission instead of analog, and improves the efficiency of the phone to find the network.
The full name of GSM is: Global System for Mobile Communications, and Chinese is the global mobile communication system, which is the second generation mobile communication technology. GSM is a standard issued by the European Committee for Standardization in 1992. It uses digital communication technology and a unified network standard to ensure the quality of communication and can develop more new services for users. The GSM data rate is 9.6Kbps.
GPRS (General Packet Radio Service) is the abbreviation of general packet radio service technology. It is a mobile data service available to GSM mobile phone users and belongs to the data transmission technology in the second generation mobile communication. GPRS can be said to be the continuation of GSM. The transmission rate of GPRS can be increased to 56 or even 114Kbps.
The main standards are GSM, TDMA, CDMA, PDC and iDEN. In comparison, the second-generation mobile communication has a high degree of confidentiality, increases the system capacity, and can realize mobile phone Internet access.
3G:
High-speed IP data network, third-generation mobile communication The biggest feature of the technology is the use of packet switching (PacketSwitching) instead of circuit switching (CircultSwitching) in data transmission. Data packets including voice, video and other multimedia content can be transmitted through the Internet.
Cellular mobile communication technology supporting high-speed data transmission. 3G service can transmit voice and data information at the same time, the rate is generally above several hundred Kbps. 3G refers to a new generation mobile communication system that combines wireless communication with multimedia communication such as the Internet. Currently, 3G has three standards: CDMA2000, WCDMA, and TD-SCDMA. 3G standard has evolved to the present, WSPA's latest evolution technology HSPA + can already support a downlink rate of 42Mbps
④4G:
All-IP data network, the fourth-generation 4G era, referring to the fourth-generation mobile communication technology, circuit switching completely disappeared. All voice calls will be digitally converted and conducted in the form of VoIP. Therefore, calling on a 4G network will be able to rely on a wired or wireless network without necessarily requiring mobile signal coverage. 4G is a combination of 3G and WLAN, and can quickly transmit data, high-quality audio, video and images. 4G can be downloaded at speeds above 100Mbps, 25 times faster than the home broadband ADSL (4 trillion), and can meet the requirements of almost all users for wireless services. In addition, 4G can be deployed in areas where DSL and cable modems do not cover, and then expand to the entire region. Obviously, 4G has unparalleled advantages. 4G is currently the fastest among all networks. The theoretical peak and downlink peak can reach 100Mbps, and it can transmit high-quality video images. The main standards are LTE, TD-LTE, and FDD-LTE. At present, global operators have been widely deployed.
⑤5G:
5G is the fifth-generation mobile communication technology. ITU divides 5G application scenarios into two categories: mobile Internet and Internet of Things. The peak theoretical transmission speed can reach 10Gbps, which is hundreds of times faster than the transmission speed of 4G network. For example, a 1G movie can be downloaded in 8 seconds. 5G communication technology with low latency, low power consumption, and high reliability is an evolutionary integrated solution for a variety of 4G wired and wireless access technologies. From 2019 to 2020, we can see that global operators will successively launch 5G commercial service trial camps, including: Internet of Things, Internet of Vehicles, Smart Healthcare, VR / AR, Industry 4.0 and other key applications, which will drive the new industrial ecological chain.
In June 2015, ITU-R has defined 3 major application scenarios for 5G in the future, namely enhanced mobile Internet service eMBB (Enhanced Mobile Broadband), massively connected IoT service mMTC (Massive Machine Type Communication) and ultra-high Reliability and ultra-low latency service uRLLC (Ultra Reliable & Low Latency Communication), and defines the capacity requirements for 5G networks from 8 dimensions such as throughput, delay, connection density and spectrum efficiency improvement.
