3G, in fact, is the third generation, which means the third generation digital communication in Chinese. 1995, the first generation of digital mobile phones, can only make voice calls; From 1996 to 1997, the second generation of digital mobile phones appeared, adding the function of receiving data, such as receiving mail or web pages; The main difference between the third generation and the first two generations is that the speed of transmitting sound and data has increased. It can handle various media forms, such as images, music and video streams, and provide various information services, including web browsing, teleconference and e-commerce.

Compared with the first generation of analog mobile phones (1G) and the second generation of GSM, TDMA and other digital mobile phones (2G), 3G communication has many names, which are defined by ITU as "IMT-2000" (International Mobile Phone 2000) and called "UMTS" by European telecom giants.

According to the standard, when the mobile terminal moves at the vehicle speed, its transmission data rate is 144kbps, when it is stationary or walking outdoors, the rate is 384kbps, and it is 2Mbps indoors. However, these requirements do not mean that the available rate of users can reach 2Mbps, because the indoor rate will also depend on the detailed frequency planning in the building and the close cooperation between organizations and operators.

At present, the 2.5G mobile communication technology that has been put into commercial use is a fusion technology from 2G to 3G. Because 3G is a huge project, involving many complicated layers, it is impossible to connect from the current 2G to 3G at once, so there is a 2.5G between 2G and 3G. HSCSD, GPRS, WAP, EDGE, Bluetoot, EPOC and other technologies are all 2.5G technologies.

HSCSD This is an upgraded version of GSM network, which can greatly increase the transmission speed to two or three times as usual. At present, both M 1 in Singapore and Singapore Telecom use HSCSD system, and the transmission speed can reach 57.6kbps.

Because GPRS has the characteristics of instant online, it is always online for users. GPRS technology also allows service providers to charge according to data transmission volume, rather than simply charging according to online time. This technology cooperates with GSM network, and the transmission speed can reach 1 15kbps.

EDGE is completely based on the current GSM standard, which can not only maximize the function of GPRS, but also provide broadband multimedia services through the current wireless network. The transmission speed of EDGE can reach 384kbps, which can be used for wireless multimedia, e-mail, network infotainment and video conference.

WAP is the first stage product of the combination of mobile communication and Internet, and it is also the most heard. This technology allows users to surf the Internet using wireless devices such as mobile phones and travel between the same stations through small screens. These same stations must also be written in WMl (Wireless Markup Language), which is equivalent to HTML (Hypertext Markup Language) on the Internet.

Prospect of 3G era

Japanese mobile communication giant NTF DoCoMo launched the world's first 3G service based on WCDMA standard on June 10. At present, Asia has become the fastest growing region of 3G, followed by Europe, and the United States is far behind in technical preparation due to lack of enthusiasm. In addition to Japan and South Korea, Thailand and Hong Kong also issued 3G licenses. Taiwan Province Province will soon issue 3G licenses. It is expected that 3G licenses will be issued in the Mainland before the end of the year, and the market is expected to issue two or three photo licenses.

3G(3rd Generation) refers to the third generation mobile communication technology. Compared with the previous two generations, the main feature of the third generation mobile communication system is that it can provide rich and colorful mobile multimedia services. Its design goal is to provide greater system capacity and better communication quality than the second-generation system, better realize seamless roaming around the world, and provide users with a variety of services including voice, data and multimedia, while considering good compatibility with the existing second-generation system.

At present, there are three main 3G standards accepted by ITU: WCDMA, CDMA2000 and TD-SCDMA. CDMA is the abbreviation of code division multiple access, which is the technical basis of the third generation mobile communication system. The first generation mobile communication system adopts frequency division multiple access (FDMA) analog modulation mode. The main disadvantages of this system are low spectrum utilization and signal interference to voice services. The second generation mobile communication system mainly adopts time division multiple access (TDMA) digital modulation mode, which improves the system capacity, and uses independent channels to transmit signaling, which greatly improves the system performance. However, the system capacity of TDMA is still limited and the handover performance is still not perfect. CDMA system shows great development potential with its advantages of simple frequency planning, large system capacity, high frequency reuse coefficient, strong anti-multipath ability, good communication quality, soft capacity and soft handover. Here are some 3G standards:

( 1) WCDMA

The full name is broadband CDMA, which is a 3G technical specification based on GSM network and a broadband CDMA technology proposed by Europe. It is basically the same as the broadband CDMA technology proposed by Japan and is being further integrated. This standard puts forward the evolution strategy of GSM(2G)-GPRS-EDGE-WCDMA(3G). GPRS stands for General Packet Radio Service, and EDGE stands for Enhanced Data Rate of GSM Evolution. These two technologies are called 2.5 generation mobile communication technologies.

(2)CDMA2000

CDMA2000 is a wideband CDMA technology developed from narrowband CDMA(CDMA IS95) technology, which is mainly promoted by the United States. This standard puts forward the evolution strategy from CDMA IS95 (2G)-CDMA 20001X-CDMA 20003x (3G). CDMA2000 1x is called the 2nd and 5th generation mobile communication technology. The main difference between CDMA20003x and CDMA2000 1x lies in the application of multicarrier technology, which improves the bandwidth by using three carriers. At present, China Unicom is adopting this scheme to transition to 3G, and has built a CDMA IS95 network.

(3)TD-SCDMA

The full name is time division-synchronous code division multiple access, which is a 3G standard proposed by China Datang Telecom Company. This standard proposes a direct transition to 3G without the intermediate link of 2.5 generation, which is very suitable for upgrading GSM system to 3G.

Respondent: Fuping11-Chief Operating Officer 13 level 4-29 08: 17.

Now "3G communication" is about to become the mantra in people's mouths, so do you know what 3G communication is? The so-called 3G, in fact, is the third generation, which means the third generation digital communication in Chinese. 1995, the first generation of digital mobile phones, can only make voice calls; The second generation digital mobile phones from 1996 to 1997 have added the function of receiving data, such as accepting emails or web pages; The main difference between the third generation and the first two generations is that the speed of transmitting sound and data has increased. It can handle various media forms, such as images, music and video streams, and provide various information services, including web browsing, teleconference and e-commerce. Compared with the first generation analog mobile phones (1G) and the second generation GSM, TDMA and other digital mobile phones (2G),

There are many names for 3G communication. ITU defines it as "IMT-2000" (International Mobile Phone 2000), and European telecom giants call it "UMTS" universal mobile telecommunications system. According to the standard, when the mobile terminal moves at the vehicle speed, its transmission data rate is 144kbps, when it is stationary or walking outdoors, the rate is 384kbps, and it is 2Mbps indoors. However, these requirements do not mean that the available rate of users can reach 2Mbps, because the indoor rate will also depend on the detailed frequency planning in the building and the close cooperation between organizations and operators.

The International Telecommunication Union (ITU) has determined three mainstream wireless interface standards for 3G communication, namely W-CDMA (Wideband Code Division Multiple Access), CDMA2000 (Multicarrier Wavelength Division Multiplexing Spread Spectrum Modulation) and TDS-CDMA (time division-synchronous code division multiple access). Among them, the W-CDMA standard mainly originated from the early third-generation wireless research activities in Europe and Japan. The system is used on the existing GSM network and can be easily converted by system providers. The main supporters of this standard are Europe, Japan and South Korea. At the end of last year, at&; T Mobile Services Branch also announced that it has chosen WCDMA as its third generation service platform. CDMA2000 system is mainly proposed by Qualcomm North America Company, and its construction cost is relatively low. Its main supporters include Japan, South Korea and North America. TD-SCDMA standard was first put forward by China, and cooperated with the international community on the basis of RTT. TD-SCDMA standard is completed and becomes a member of CDMA TDD standard. This is a pioneering work in the field of mobile communication in China, and also China's contribution to the development of the third generation mobile communication. In the competition with the 3G standards proposed by Europe and America respectively, TD-SCDMA proposed by China has officially become one of the global 3G standards, which indicates that China has entered a leading position in the field of mobile communication.

3G mobile phone is the product of the integration of communication industry and computer industry. Compared with the previous mobile phone, the difference is too great, so more and more people begin to call this new mobile communication product "personal communication terminal". Even the most layman in the communication industry can easily judge whether a mobile phone is the "third generation" from the appearance: the third generation mobile phones are all large color display screens, which are often touched. 3G mobile phone can not only complete high-quality daily communication, but also carry out multimedia communication. Users can write and draw directly on the touch screen of 3G mobile phone and send it to another mobile phone, which may take less than one second. Of course, you can also send this information to the computer or download some information from the computer; Users can use 3G mobile phones to surf the Internet directly, check emails or browse the web. There will be many models of 3G mobile phones with their own cameras, which will allow users to hold computer meetings with their mobile phones and even make digital cameras "redundant".

3G communication is a mobile communication service introduced in the mobile communication market after the first generation of analog technology, and it has been introduced into the agenda in the vigorous development of the second generation digital mobile communication market. With the rise of Internet data services and the improvement of fixed access rate (HDSL, ADSL, VDSL), 3G mobile communication system has also seen the dawn of the market, and attracted more and more attention from telecom operators, communication equipment manufacturers and ordinary users.