What is 1G/2G/3G/4G/5G

What is 1G/2G/3G/4G/5G

Reference: http://www.360doc.com/content/14/1213/22/5458405_432718054.shtml

Introduction

1. 1G: Represents the first generation of mobile communication technology. In the early 1980s, the first generation of analog technology (1G) appeared for the first time. As a standard for cellular phones, it was characterized by only voice. Nowadays, analog cellular technology has withdrawn from the stage of history.
2. 2G: The second-generation mobile communication technical specifications, with digital voice transmission technology as the core. Generally defined as the inability to directly transmit information such as e-mail, software, etc.; it only has phone communication technical specifications such as time and date transmission. However, SMS can be implemented in some of its specifications. It is usually called "Personal Communication Service" (foreign language abbreviation: PCS) in the United States.
3. 2.5G: The 2.5G (Generation) mobile communication technology that has been commercially applied is a cohesive technology from 2G to 3G. It breaks through the restriction of 2G circuit switching technology on data transmission rate and introduces packet switching technology to enable data transmission. A qualitative breakthrough in speed is a transitional technology between 2G and 3G. The emergence of 2.5G is mainly due to the fact that 3G is a rather large project with many and complicated levels. It is impossible to move from 2G to 3G immediately. Representative: GPRS, HSCSD, WAP, EDGE, Bluetooth (Bluetooth), EPOC and other technologies.
4. 3G: The third-generation mobile communication technology refers to cellular mobile communication technology that supports high-speed data transmission. 3G service can transmit voice and data information at the same time. 3G is a generation of mobile communication system that combines wireless communication with multimedia communication such as the Internet.
5. 4G: The fourth-generation mobile communication network standard technology. The fourth generation of mobile communication technology adopts more new technologies that have not been used before, and introduces technical communication. It mainly uses a network architecture based on routing technology. By using unlimited frequency technology, its system is better than the previous two generations. More perfect. With a smaller amount of wireless spectrum, you can do the same things as before, and the speed can still remain relatively fast. The key technologies of the fourth-generation mobile communication system include channel transmission; high-speed access technology, modulation and information transmission technology with strong anti-interference ; high-performance, miniaturization and low-cost adaptive array smart antennas; large-capacity, low-cost Wireless interface and optical interface; system management resources; software radio, network structure protocol, etc. The fourth-generation mobile communication system is mainly based on Orthogonal Frequency Division Multiplexing (OFDM) as its technical core.
6. The fifth-generation mobile communication technology (English: 5th generation mobile networks or 5th generation wireless systems, 5th-Generation, referred to as 5G or 5G technology) is the latest generation of cellular mobile communication technology, namely 4G (LTE-A, WiMax), 3G ( Extension after UMTS, LTE) and 2G (GSM) systems. The performance goals of 5G are high data rates, reduced latency, energy savings, cost reduction, increased system capacity and large-scale device connections.

standard

1. The main 2G standards are GSM and CDMA, and most of them except the United States use zhiGSM;
2. There are four standards for 3G: CDMA2000, WCDMA, TD-SCDMA (used by China Mobile 3G), and WiMAX.
3. 4G is LTE divided into TDD and FDD.

Network standard

The network standard usually refers to the network type of the mobile operator.

	2G	3G	4G
mobile	GSM	TD-SCDMA	TD-LTE
Unicom	GSM	WCDMA	D-LTE/FDD-LTE
telecommunications	CDMA	CDMA2000	TD-LTE/FDD-LTE

TDD（时分双工） • 上行和下行通信使用同一频率信道的不同时隙，用时间来分离接收和传送信道，某个时间段由基站发送信号给移动台，另外的时间由移动台发送信号给基站。基站和移动台之间必须协同一致才能顺利工作。 FDD（频分双工） • 特点是在分离的两个对称频率信道上，系统进行接收和传送，以保证频段来分离接收和传送信道。

Frequency band

The frequency of the network standard refers to the difference of each network frequency band. The country has divided several different frequency bands so that they can run on different frequency bands without interfering with each other.
We compare the models of different mobile phone networks to different stations of the radio. We know that each station of the radio corresponds to a single frequency, and the different modes of the mobile phone network also correspond to the frequency range. The country has divided several different frequency bands so that they can operate on different frequency bands in an orderly manner without interfering with each other.

China Mobile TD-LTE: Support frequency band 38, 39, 40
China Unicom TD-LTE: Support frequency band 40, 41
China Telecom TD-LTE: Support frequency band 40, 41
China Unicom FDD-LTE: Support frequency band 3
China Telecom FDD-LTE: Support band 3

FDD-LTE:

TDD-LTE: