UMTS - WCDMA Technology


The first Multiple Access Third Generation Partnership Project (3GPP) Wideband Code Division networks (WCDMA) were launched in 2002. At the end of 2005, there were 100 WCDMA networks open and a total of more than 150 operators with licenses for frequencies WCDMA operation. Currently, WCDMA networks are deployed in UMTS band of around 2 GHz in Europe and Asia, including Japan and America Korea. WCDMA is deployed in the 850 and 1900 of the existing frequency allocations and the new 3G band 1700/2100 should be available in the near future. 3GPP has defined WCDMA operation for several additional bands, which are expected to be commissioned in the coming years.

As WCDMA mobile penetration increases, it allows WCDMA networks to carry a greater share of voice and data traffic. WCDMA technology provides some advantages for the operator in that it allows the data, but also improves the voice of base. Voice capacity offered is very high due to interference control mechanisms, including frequency reuse of 1, fast power control, and soft handover.

WCDMA can offer a lot more voice minutes to customers. Meanwhile WCDMA can also improve broadband voice service with AMR codec, which clearly provides better voice quality than fixed telephone landline. In short, WCDMA can offer more voice minutes with better quality.

In addition to the high spectral efficiency, third-generation (3G) WCDMA provides even more dramatic change in capacity of the base station and the efficiency of the equipment. The high level of integration in the WCDMA is achieved due to the broadband carrier: a large number of users supported by the carrier, and less radio frequency (RF) carriers are required to provide the same capacity.

With less RF parts and more digital baseband processing, WCDMA can take advantage of the rapid evolution of digital signal processing capability. The level of integration of the high base station enables efficient building high capacity sites since the complexity of RF combiners, additional antennas or power cables can be avoided. WCDMA operators are able to provide useful data services, including navigation, person to person video calls, sports and video and new mobile TV clips.

WCDMA enables simultaneous voice and data which allows, for example, browsing or email when voice conferencing or video sharing in real time during voice calls.

The operators also offer mobile connectivity to the Internet and corporate intranet with maximum bit rate of 384 kbps downlink and both uplink. The first terminals and networks have been limited to 64 to 128 kbps uplink while the latter products provide 384 kbps uplink.


3G wireless service has been designed to provide high data speeds, always-on data access, and greater voice capacity. Listed below are a few notable points −

  • The high data speeds, measured in Mbps, enable full motion video, high-speed internet access and video-conferencing.

  • 3G technology standards include UMTS, based on WCDMA technology (quite often the two terms are used interchangeably) and CDMA2000, which is the outgrowth of the earlier CDMA 2G technology.

  • UMTS standard is generally preferred by countries that use GSM network. CDMA2000 has various types, including 1xRTT, 1xEV-DO and 1xEV-DV. The data rates they offer range from 144 kbps to more than 2 mbps.

Sub-systems of 3G Network

A GSM system is basically designed as a combination of three major subsystems −

  • Network Subsystem (NSS) − MSC/VLR, HLR, AuC, SMSC, EIR, MGW. Common for both 2G & 3G Network.

  • UTRAN − RNC & RBS.

  • Operation and maintenance Support Subsystem (OSS).

There are three dominant interfaces, namely,

  • IuCS − Between RNC and MSC for speech & Circuit data;

  • IuPS − Between RNC & SGSN for packet data;

  • Uu interface − Between the RNC and MS.