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3g [1], which is called 3rd Generation, means the third generation digital communication in Chinese.
The first generation analog mobile phone (1G) which came out in p>1995 can only make voice calls;
In p>1996-1997, the second generation of GSM, CDMA and other digital mobile phones (2G) added the function of receiving data, such as receiving emails or web pages.
3G was not born in 29, it was the product of the last century, and it was already produced abroad as early as 27. In 28, China also successfully developed China 3G, and its network transmission speed can reach 2G per second, which is equivalent to only one second for the next movie. In Japanese and Korean movies such as My Barbarian Girlfriend at the end of 199s, the video phone that the heroine used to let the other side see herself was one of the important applications of 3G technology. The application of 3G in Japan, South Korea and other countries was at the end of last century. At present, 3.5G or even 4G networks have been put into trial operation in some foreign regions.
The third generation (3G) that came out in p>29 is mainly different from the previous two generations in the speed of transmitting sound and data. It can better realize seamless roaming around the world, handle various media forms such as images, music and video streams, and provide various information services including web browsing, teleconference and e-commerce. At the same time, it should also consider its good compatibility with the existing second generation system. 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 driving environments, respectively. (This value will change according to the network environment). [edit this paragraph ]3G standards
3G standards: they are WCDMA, CDMA2, TD-SCDMA and WiMAX respectively.
in may 2, the international telecommunication union (ITU) determined four mainstream wireless interface standards, namely WCDMA, CDMA2, TD-SCDMA and WiMAX, and wrote them into the 3G technical guidance document "international mobile communication plan 2" (IMT—2 for short). CDMA is the abbreviation of Code Division Multiple Access, which is the technical basis of the third generation mobile communication system. The first generation of mobile communication system adopts frequency division multiple access (FDMA) analog modulation mode. The main disadvantages of this system are low spectrum utilization and signaling interference with 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, but the system capacity of TDMA is still limited and the handover performance is still not perfect. CDMA system shows great development potential because of its 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) W-CDMA
, also known as WCDMA, also known as Wideband CDMA, also known as CDMA Direct Spread, which means wideband code division multiple access. This is a 3G technical specification developed 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. The supporters of W-CDMA are mainly European manufacturers with GSM system, and Japanese companies are more or less involved, including Ericsson, Alcatel, Nokia, Lucent and Nortel in Europe and America, as well as NTT, Fujitsu and Sharp in Japan. This standard puts forward the evolution strategy of GSM(2G)-GPRS-EDGE-WCDMA(3G). This system can be set up on the existing GSM network, and it can be easily transitioned for system providers. It is expected that the acceptance of this new technology will be quite high in Asia where GSM system is quite popular. Therefore, W-CDMA has inherent market advantages.
(2)CDMA2
CDMA2 is a wideband CDMA technology developed from narrowband CDMA(CDMA IS95) technology, also known as CDMA Multi-Carrier. It was proposed by Qualcomm North America Company of the United States, with Motorola, Lucent and Samsung of South Korea participating, and South Korea is now the leader of this standard. This system is derived from the narrow-band CDMAOne digital standard, and can be directly upgraded from the original CDMAOne structure to 3G, with low construction cost. But at present, CDMA is only used in Japan, South Korea and North America, so there are not as many supporters of CDMA2 as W-CDMA. However, the research and development technology of CDMA2 is the fastest among the current standards, and many 3G mobile phones have taken the lead. This standard puts forward the evolution strategy from CDMA IS95 (2G)-CDMA 21x-CDMA 23x (3G). CDMA21x is called the 2.5 generation mobile communication technology. The main difference between CDMA23x and CDMA21x lies in the application of multi-carrier technology, which improves the bandwidth by adopting three carriers. At present, China Telecom is adopting this scheme to transition to 3G, and has built a CDMA IS95 network.
(3)TD-SCDMA
is called Time Division-Synchronous CDMA (Time Division Synchronous CDMA), which is a 3G standard independently formulated by Chinese mainland. On June 29th, 1999, China Institute of Telecommunications Science and Technology (Datang Telecom) proposed it to ITU. This standard integrates the international leading technologies such as smart wireless, synchronous CDMA and software radio, and has unique advantages in spectrum utilization, flexibility in service support, frequency flexibility and cost. In addition, due to the huge market in China, the standard has attracted the attention of major telecom equipment manufacturers, and more than half of the equipment manufacturers in the world have announced that they can support the TD-SCDMA standard. 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.
(4) WiMAX
The full name of WiMAX is Worldwide Interoperability for Microwave Access, also known as 82.16 wireless metropolitan area network, which is another broadband wireless connection scheme for enterprises and home users. Combining this technology with microwave equipment that needs authorization or no authorization will expand the broadband wireless market and improve the awareness of enterprises and service providers because of its low cost. On October 19th, 27, at the wireless communication plenary meeting held by the International Telecommunication Union in Geneva, WiMAX was officially approved as the fourth global 3G standard after WCDMA, CDMA2 and TD-SCDMA.
3G China is the registered trademark of the largest professional 3G mobile phone network business service platform in China. 3G China includes industries, enterprises, products, services and trade functions, etc. It is an integrated system service platform for enterprises to realize wap website construction, industry new media communication, mobile business operation and wireless timely communication on 3G network. Its promotion concept of industry integration and brand-new marketing mode of 3G network wireless communication form a new 3G wireless information network. All its functions and value-added services provide users with a perfect and efficient 3G experience, which perfectly embodies the strong business connotation in the 3G era.
1. Product features
1. Easy to use, easy to build, continuous improvement, automatic update without manual work
2. High technology, top-end search technology, powerful and not outdated
3. Adapting to business changes on demand, quick response in the first time
4. Low cost, rich in functions. Zero-cost revision of DIY
II. Six advantages of 3G China
1. Authoritativeness:
1) The name of the applied industry platform is protected by the state
2) Independent and powerful authoritative media is established in the industry
3) Brand building while publishing industry information
2. Monopoly:
Having an industry platform, Let your peers only publish information on your platform
3. Scarcity:
1) Only one mobile phone industry platform is selected for each industry to operate on behalf of the enterprise
2) The number of certified industry platforms is limited, with first come first served
4. Value-added:
1) The number of national certified industry platforms is limited, which has long-term appreciation potential
2) The industry platforms operate. Attract people's attention
3) The income model of membership fee+advertising fee is profitable
5. Timeliness:
Focus the attention of 6 million customers on the square inch, know the market trend with every move, plan and make a decisive victory
6. Simplicity:
Training and operating one-stop service. Senior operation consultant guides [edits this paragraph ]3G parameters
WCDMA
RTT FDD
Asynchronous CDMA system: no GPS
Bandwidth: 5MHz
Chip rate: 3.84Mcps
China band: 194MHz-1955MHz (uplink) and 213MHz -2145MHz.
TD-SCDMA
RTT TDD
synchronous CDMA system: GPS
bandwidth: 1.6MHz
chip rate: 1.28Mcps
China frequency band: 188-192MHz, 21-225 MHz
23-24 MHz
CDMA 2
RTT FDD
Synchronous CDMA system: with GPS
bandwidth: 1.23MHz
chip rate: 1.2288Mcps
China frequency band: 192 MHz-199.
WiMax
Worldwide microwave interconnection, another name is 82.16
Bandwidth: 1.5M to 2MHz
Maximum access speed: 7M
Maximum transmission distance: 5km
Chip rate: unknown
China frequency band: (not available yet) [Edit this paragraph] Convenient life in p>3G era.
●3G is a soap opera that you can't miss by train;
●3G is an image sent back from the scene to the headquarters for analysis;
●3G is to enjoy your wonderful holiday in Morocco with friends.
The 3G road in China has just begun. The first popular 3G application is "wireless broadband Internet access", and 6 million mobile phone users can access the Internet anytime and anywhere. The streaming media service of wireless Internet will gradually become dominant. The core applications of 3G include:
1. Broadband Internet access
Broadband Internet access is a very important function of 3G mobile phones. At that time, we can send and receive voice mails, write blogs, chat, search, download ringtones, etc ... Now many people think that these functions and applications on mobile phones will wait until the 3G era, but in fact, the current wireless Internet portal can already be provided. Although the current GPRS network speed is not very satisfactory, it is no longer a dream that mobile phones will become small computers when the 3G era comes.
2. Video call
In the p>3G era, the traditional voice call is already a very weak function. By then, new services such as video call and voice mail will be the mainstream, and the traditional voice call charges will be reduced, while the visual impact will be strong, and the fast and direct video call will become more popular and develop rapidly.
The most talked about in 3G era is the video calling function of mobile phone, which is also one of the most popular 3G services abroad. I believe many people have used the video chat function of QQ, MSN or Skype to chat "face to face" with distant relatives and friends. In the future, relying on the high-speed data transmission of 3G network, 3G mobile phone users can also "face-to-face". When you make a video call with a 3G mobile phone, instead of putting the phone to your ear, face the phone and put on a wired headset or a Bluetooth headset. You will see the other person's image on the phone screen, and you will be recorded and sent to the other party.
3. Mobile TV
From the perspective of operators, the issuance of 3G licenses has solved a great technical obstacle, and the construction of standards such as TD and CMMB has also promoted the development of the whole industry. Mobile streaming media software will become the most used mobile TV software in the 3G era, which will improve the smoothness of video images and picture quality, break through the technical bottleneck and be really applied on a large scale.
4. Wireless search
For users, this is a practical mobile network service, which can also be quickly accepted. Searching by mobile phone anytime and anywhere will become a common life habit for more mobile phone users.
5. Mobile music
In Japan, where the wireless Internet is mature, mobile music is the most beautiful landscape, and downloading music from the Internet through mobile phones is 5 times that of computers. In the 3G era, as long as a mobile phone music software is installed on the mobile phone, the mobile phone can be turned into a music box anytime and anywhere through the mobile phone network, and countless songs can be easily stored, with faster download speed and negligible traffic consumption.
6. Mobile shopping
Many people have the experience of shopping on Taobao, but the mobile mall is still a new thing for many people. In fact, mobile e-commerce is the favorite of mobile Internet users in the 3G era. At present, 9% of Japanese and Korean mobile phone users are used to spending on their mobile phones, even