百木通的效果怎么样:What's 3G technolige? Please answer it in English.

3G (wCDMA, CDMA-2000, UMTS, FOMA) in Japan FAQ
1. What are third generation (3G) wireless communications? Second generation (2G) cellular data networks in Japan deliver data rates up to 9.6 kbps for upload and up to 29.8 kbps for download.
PHS networks in Japan deliver data rates up to 128 kbps for terminals which are not moving at high speeds (e.g. PHS does not connect well in high-speed trains).
Third generation (3G) wireless networks in Japan deliver datarates from 64 kbps for upload and on the order of 200 kbos for downlad. Increasingly 3G networks in Japan are upgraded to deliver data connection rates on the order of 2 to 10 Mbps. These higher speeds allow the transmission of video and two-way video telephony, rapid download of movie sketches, music and JAVA applications. Other data connections, e.g. download of information or JAVA applets, are also several times faster on 3G networks then on older 2G networks.
In Japan there are three parallel, independent and competing 3G networks. Costs to the carrier are lower, so that competition drives prices down. 2. Which networks are there in Japan and how many 3G users are there? KDDI/AU, NTT-DoCoMo and Vodafone operate 3G mobile networks in Japan. The following figure shows the user numbers as of January 2005:

2. What is the "killer application" for 3G? Is there one at all? If there is a "killer application" for 3G, its mobile music! Chaku-Uta downloads on KDDI-AU mobile phones have similar download numbers as iTunes in the US with a very much smaller potential user pool. One can therefore safely say, that mobile music downloads seem to be substantially more attractive for paying users than conventional fixed line internet music downloads.

3G
From Wikipedia, the free encyclopedia.

3G (or 3-G) is short for third-generation mobile telephone technology. The services associated with 3G provide the ability to transfer both voice data (a telephone call) and non-voice data (such as downloading information, exchanging email, and instant messaging).

In marketing 3G services, video telephony has often been used as the flagship killer application for 3G. A certain euphoria was created, which led to very large spectrum licencing fees in many countries especially in Europe. Since these spectrum licensing fees were collected many years before any income could be expected from 3G business, and since huge investments are necessary to build the 3G networks, many telecommunication operators were maneuvered into great financial difficulties, which greatly delayed 3G roll-out in all countries except Japan and Korea, where such spectrum licensing fees were avoided since priority was set on national IT infrastructure development.

The first country which introduced 3G on a large commercial scale was Japan. In 2005 about 40% of subscribers use 3G networks only, and 2G is on the way out in Japan. It is expected that during 2006 the transition from 2G to 3G will be largely completed in Japan, and upgrades to the next 3.5G stage with 3 Mbit/s data rates is underway.

The successful 3G introduction in Japan shows that Video telephony is not a killer application for 3G networks after all. Actually, the real-life usage of video telephony on 3G networks is only a very very small fraction of all services. On the other hand, downloading of music finds very strong demand by customers. Music downloads were pioneered by KDDI with the EZchakuuta and the Chaku Uta Full services.

Next generation (3G) wireless networks are not IEEE 802.11 networks. Rather, they are networks dedicated to personal devices, including PDAs and cellular telephones.

Contents
1 3G standards
1.1 UMTS (W-CDMA)
1.2 CDMA 2000
1.3 TD-SCDMA
1.4 Wideband CDMA
1.5 UMTS TDD
2 List of countries that have deployed 3G
3 References
4 See also
5 External links

3G standards
3G technologies are an answer to the International Telecommunications Union's IMT-2000 specification. Originally, 3G was supposed to be a single, unified, worldwide standard, but in practice, the 3G world has been split into four camps.

UMTS (W-CDMA)
UMTS (Universal Mobile Telephone System), based on W-CDMA technology, is the solution generally preferred by countries that used GSM, centered in Europe. UMTS is managed by the 3GPP organization also responsible for GSM, GPRS and EDGE.

FOMA, launched by Japan's NTT DoCoMo in 2001, is generally regarded as the world's first commercial 3G service. However, while based on W-CDMA, it is not generally compatible with UMTS (although there are steps currently under way to remedy the situation).

CDMA 2000
The other significant 3G standard is CDMA2000, which is an outgrowth of the earlier 2G CDMA standard IS-95. CDMA2000's primary proponents are outside the GSM zone in the Americas, Japan and Korea. CDMA2000 is managed by 3GPP2, which is separate and independent from UMTS's 3GPP. The various types of transmission technology used in CDMA2000 include 1xRTT, CDMA2000-1xEV-DO and 1xEV-DV.

CDMA 2000, has a data rates of 144 kbit/s to over 3 Mbit/s. Adopted by the International Telecommunication Union ITU

Arguably the most successful introduction of CDMA-2000 3G networks is Japan's KDDI, which under the AU brand has more than 20 million 3G subscribers. Since December 2003, KDDI has upgraded the CDMA2000-1x network to CDMA2000-1xEV-DO which achieves data rates up to 2.4 Mbit/s. In 2006, AU plans to upgrade the network to above 3 Mbit/s.

TD-SCDMA
A less well known standard is TD-SCDMA which is being developed in the People's Republic of China by the companies Datang and Siemens. They are predicting an operational system for 2005.

Wideband CDMA
Supports speeds between 384 kbit/s and 2 Mbit/s. When this protocol is used in a WAN, the top speed is 384 kbit/s. When it is used in a LAN, the top speed is 2 Mbit/s. Also adopted by the ITU.

UMTS TDD
Supports speeds of up to 3 Mbit/s. UMTS TDD Alliance

List of countries that have deployed 3G
Countries that have commercial 3G networks include:

Argentina (CDMA2000 1x)
Australia (W-CDMA) (CDMA2000 1x)
Austria (W-CDMA)
Azerbaijan (CDMA2000 1x)
Belarus (CDMA2000 1x)
Belgium (W-CDMA)
Bermuda (CDMA2000 1x)
Brazil (CDMA2000 1x)
Canada (CDMA2000 1x)
Chile (CDMA2000 1x)
China (CDMA2000 1x)
Colombia (CDMA2000 1x)
Cyprus (W-CDMA)
Denmark (W-CDMA)
Dominican Republic (CDMA2000 1x)
Ecuador (CDMA2000 1x)
Finland (W-CDMA)
Georgia (CDMA2000 1x)
Germany (W-CDMA)
Greece (W-CDMA)
Guatemala (CDMA2000 1x)
Hong Kong (W-CDMA)
Hungary (W-CDMA)
India (CDMA2000 1x)
Indonesia (CDMA2000 1x)
Ireland (W-CDMA)
Israel (W-CDMA)
Italy (W-CDMA)
Jamaica (CDMA2000 1x)
Japan (W-CDMA, CDMA2000 1x)
Kazakhstan (CDMA2000 1x)
Kyrgyzstan (CDMA2000 1x)
Malaysia (W-CDMA deployed by Digi, Maxis and Celcom)
Mexico (CDMA2000 1x)
Moldova (CDMA2000 1x)
Netherlands (W-CDMA)
New Zealand (CDMA2000 1x) (W-CDMA in testing) (3GSM)
Nicaragua (CDMA2000 1x)
Nigeria (CDMA2000 1x)
Norway (W-CDMA)
Pakistan (CDMA2000 1x)
Panama (CDMA2000 1x)
Peru (CDMA2000 1x)
Poland (CDMA2000 1x)
Portugal (W-CDMA)
Romania (W-CDMA offered by Connex, CDMA2000 1x offered by Zapp Mobile)
Russia (CDMA2000 1x)
Singapore (W-CDMA)
Slovenia (W-CDMA)
South Korea (CDMA2000 1x)
South Africa (W-CDMA offered by Vodacom and MTN)
Spain (W-CDMA)
Sri Lanka (W-CDMA by Dialog, CDMA2000 1x by Suntel)
Sweden (W-CDMA)
Taiwan (CDMA2000 1x)(W-CDMA)
Tajikistan (W-CDMA)
Thailand (CDMA2000 1x)
Ukraine (CDMA2000 1x)
United Arab Emirates (W-CDMA)
United Kingdom (W-CDMA)
United States (CDMA2000 1x) (W-CDMA in testing)
Uzbekistan (CDMA2000 1x)
Venezuela (CDMA2000 1x)
Vietnam (CDMA2000 1x)

3G