(IDG) -- Wireless videophones and high-speed Internet access are a reality with the world's first third-generation or "3G" mobile services, which were launched on October 1 by NTT DoCoMo in Tokyo.
Third-generation wireless: A group of wireless technologies that move from circuit-switched communications to wireless broadband, high-speed, packet-based networks. These are preceded by first-generation analog, and second-generation digital, communication technologies.
What is 3G wireless?
So-called 3G wireless networks are capable of transferring data at speeds of up to 384Kbps. Average speeds for 3G networks will range between 64Kbps and 384Kbps, quite a jump when compared to common wireless data speeds in the United States that are often slower than a 14.4Kb modem. 3G is considered high-speed or broadband mobile Internet access, and in the future 3G networks are expected to reach speeds of more than 2Mbps.
The 3G technologies are turning phones and other devices into multmedia players, making it possible to download music and video clips. The new service is called the "freedom of mobile multimedia access" (FOMA), and it uses wideband code division multiple access (W-CDMA) technology to transfer data over its networks. W-CDMA sends data in a digital format over a range of frequencies, which makes the data move faster, but also uses more bandwidth than digital voice services. W-CDMA is not the only 3G technology; competing technologies include CDMAOne, which differs technically, but should provide similar services.
FOMA services are available within a 20-mile radius around the center of Tokyo, the company plans to introduce it to other Japanese cities by the end of the year. But services and phones are expensive and uptake of this market is expected to be slow.
What is 2.5G?
When the wireless industry realized that it was going to be costly and technologically challenging to upgrade to 3G networks, an interim stage emerged called 2.5G. These networks transfer data at speeds of up to 114Kbps, which is faster than traditional digital (2G) networks. They are always on. A phone with 2.5G services can alternate between using the Net, sending or receiving text messages, and making phone calls without losing its connection.
While Japan has had 2.5G services for more than a year and Europe also has had 2.5G services, the U.S. is just beginning to make these same services available. Seattle was the first U.S. city to acquire 2.5G services, in July. Wireless carriers are working on expanding those services to more cities in 2001. The dominant 2.5G technology is general packet radio service (GPRS), which is always on and gives users a connection to the Internet and e-mail.
Why is the U.S. so far behind the rest of the world?
The U.S. lags behind the rest of the world when it comes to wireless technologies for a number or reasons. The telecommunications infrastructure in the U.S. is more developed than many European and Asian countries. As a result, the demand for wireless devices has been lower in the U.S because consumers have other lower-cost options.
Also, the U.S. has a number of competing technical standards for digital services, while European and Asian countries are predominately centered around one group of standards in the global systems for mobile communication (GSM) family.
The 3G wireless services also require additional bandwidth (compared to 2G services), but many U.S. wireless companies don't have licenses for enough airwaves to provide such services.
ref:http://edition.cnn.com/2001/TECH/industry/10/22/3g.defined.idg/index.html
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