3G Knowledge Popularization

3G, all called 3rd Generation, means the third generation of digital communication in Chinese.

The first generation analog mobile phone (1G) introduced in 1995 can only make voice calls;

Digital mobile phones (2G), such as second-generation GSM, time division A, etc., which appeared between 1996 and 1997, have added the ability to receive data, such as e-mail or web pages.

3G wasn't born in 2009. It was the product of the last century. It was already produced abroad as early as 2007. China also successfully developed 4G in 2008. Its network transmission speed can reach 2G per second, which is equivalent to the next movie in just one second.In Japanese and Korean movies such as My Barbaric Girlfriend in the late 1990s, one of the important applications of 3G technology is that the heroine uses a video phone that lets her partner see her.The use of 3G in countries such as Japan and South Korea was at the end of the last century.At present, some foreign regions have tried to run 3.5G or even 4G networks.

(Following are misleading) The main difference between the third generation (3G) and the first two in 2009 is the increased speed at which sound and data are transmitted. It enables better seamless roaming around the world and handles a variety of media formats, including images, music, video streaming, etc., offering web pagesView, teleconferencing, e-commerce and other information services, but also to consider good compatibility with existing second-generation systems.In order to provide this service, wireless networks must be able to support different data transmission speeds, that is, at least 2Mbps (megabits per second), 384kbps (kilobits per second) and 144kbps in indoor, outdoor and vehicle environments, respectively.(This value varies depending on the network environment).

3G standards, the International Telecommunication Union (ITU) has currently identified four major global 3G standards, namely WCDMA, CDMA2000, TD-SCDMA and WiMAX.

In May 2000, the International Telecommunication Union (ITU) of 3G Standards identified the four main wireless interface standards of W-CDMA, CDMA2000, TD-SCDMA and WiMAX, and wrote the guidance document for 3G technology, International Mobile Communication Plan 2000 (IMT— 2000).CDMA is the abbreviation of Code Division Multiple Access and the technical basis of the third generation mobile communication system.The first generation mobile communication system uses the analog modulation mode of frequency division multiple access (FDMA). The main drawbacks of this system are low frequency spectrum utilization and signaling interferes with the voice service.The second generation mobile communication system mainly uses time division multiple access (F4A) digital modulation to improve the system capacity, and uses independent channel to transmit signaling, which greatly improves the system performance. However, the system capacity of the F4A is still limited, and the cross-zone switching performance is still imperfect.The CDMA system shows great potential for development because of its simple frequency planning, large system capacity, high frequency multiplexing factor, strong anti-multipath capability, good communication quality, soft capacity, soft switching, etc.Here are some standards for 3G:

(1) W-CDMA

Also known as WCDMA, fully known as Wideband CDMA, also known as CDMA Direct Spread, means broadband code multiple access. This is a 3G technical specification based on GSM network, which is proposed by Europe. It is basically the same as the broadband CDMA technology proposed by Japan and is currently being further integrated.W-CDMA is mainly supported by European manufacturers mainly based on GSM system, and Japanese companies are more or less involved, including Ericsson, Alcatel, Nokia, Lucent, Nortel, NTT, Fujitsu, Sharp and other manufacturers in Japan.The standard proposed the evolution strategy of GSM(2G) - GPRS-EDGE-WCDMA (3G).The system can be mounted on existing GSM networks, making it easier for system providers to transition, but Asia, where the GSM system is fairly ubiquitous, is expected to see considerable acceptance of this new technology.Therefore, W-CDMA has inherent market advantages.

(2) CDMA2000

CDMA2000 is a broadband CDMA technology developed from narrowband CDMA (CDMA IS95), also known as CDMA Multi-Carrier. It was proposed by Qualcomm North America, Motorola, Lucent and Samsung Korea joined later. Korea is now the leader of the standard.Derived from the narrow-band CDMA One digital standard, this system can be upgraded directly from the original CDMA One structure to 3G with low cost.However, currently only Japan, South Korea and North America use CDMA, so there are not as many supporters of CDMA2000 as W-CDMA.However, the research and development technology of CDMA2000 is currently the fastest in all standards, and many 3G mobile phones have been introduced first.The standard proposes an evolving strategy from CDMA IS95 (2G) - CDMA20001x - CDMA20003x (3G).CDMA20001x is called 2.5 generation mobile communication technology.The main difference between CDMA20003x and CDMA20001x is the application of multi-carrier technology, which improves the bandwidth by using three carriers.At present, China Telecom is using this scheme to transition to 3G, and has built a CDMA IS95 network.