WCDMA (Wideband Code Division Multiple Access)

WCDMA ( Wideband Code Division Multiple Access ) is a third generation wireless communication technology. W-CDMAWideband CDMA is a 3GPP specifically formulated, based on the GSM MAP core network, UTRAN ( UMTS UMTS terrestrial radio access network ) is a radio interface of the third generation mobile communication system. At present, WCDMA Release 99, Release 4, Release 5, Release 6 version. China Unicom currently uses the 3G communication standards.

W-CDMA ( wideband code division multiple access) is a ITU ( International Telecommunication Union ) standard, it is from wideband code division multiple access ( CDMA ) evolved, from the official is considered IMT-2000 direct expansion, and now the market usually provide the technology, it can provide mobile and portable wireless device with the higher data rate. WCDMA direct sequence spread spectrum code division multiple access ( DS-CDMA ), frequency division duplexing ( FDD ) mode, the chip rate for 3.84Mcps, carrier bandwidth of 5MHz. Based on Release 99 / Release 4 version, available on the 5MHz bandwidth, provide the highest 384kbps user data transfer rate. W-CDMA is able to support mobile / handheld device between the speech, image, data and video communication, speed can reach 2Mb / S ( for local) or 384Kb / S ( for broadband network ). The input signal to be digitized, and then in a wide spectral range with coded spread spectrum mode transmission. Narrow band CDMA is using 200KHz width of the carrier, while W-CDMA is the use of a 5MHz width of the carrier frequency. W-CDMA by ETSI NTT DoCoMo as a wireless interface for their 3G FOMA network development. Later, NTTDocomo to ITU a detailed specification as a like IMT-2000 as a candidate of the international 3G standard. The International Telecommunications Union ( ITU ) W-CDMA IMT-2000 3G is finally accepted as a standard part of the family. Later W-CDMA was selected for UMTS wireless interface, as the successor of GSM 3G technology or project. Despite the name of misunderstanding with CDMA are very similar, but has little relationship with CDMA W-CDMA. Many are small to see the different standpoint. In the mobile phone, the term CDMA can refer to the code division multiple access spread spectrum multiplexing technique, can also refer to the United States of America Qualcomm ( Qualcomm ) development including IS-95 / CDMA1X and CDMA2000 ( IS-2000 ) of the CDMA family of standards.

Development process

History, European Telecommunications Standards Institute ( ETSI ) after GSM began to study the 3G standard, in which there are several alternatives are based on direct sequence spread spectrum code division multiple access, while the Japanese third generation research is also used in wideband code division multiple access technology, thereafter, leading to the two fusion, in the 3GPP organization development the third generation mobile communication system UMTS, and presented it to the International Telecommunications Union ( ITU ).

International Telecommunication Union eventually accepted WCDMA IMT-2000 as part of the 3G standard.

In 2001, Japan's NTT DoCoMo FOMA is the world's first commercial operation of WCDMA services. W-CDMA mobile phone using J-Phone Japanese telephone (now software bank ) has been following the launch of WCDMA services based, claiming " Vodafone global standard" UMTS compatible ( though there is controversy in 2004 when ).

At the beginning of 2003, and recorded in Whampoa　 gradually in the global operation of their UMTS networks (3 ).

Most of the European GSM operators have launched the UMTS service.

Vodafone in 2004 February in several European UMTS network operation. Vodafone in other countries ( including Australia and New Zealand ) construction of UMTS network.

AT&T wireless ( now belongs to Cingular Wireless ) in some city opened a UMTS. Because although the merger makes network construction progress was delayed, but the Cingular has announced plans to deploy WCDMA in 2005 and HSDPA.

TeliaSonera started in October 13, 2004 in Finland to provide the rate of 384kbps WCDMA services. The service is available in the main city. Communication rate of about $2 per megabyte.