3G/UMTS

3G – History:

First generation wireless, or 1G, refers to analog networks introduced in the mid-1980s. Examples include Advanced Mobile Phone Service (AMPS) used in North America and Total Access Communications System (TACS) used in the UK. As mobile communications grew in popularity, networks often became overloaded, resulting in busy signals and dropped calls. The solution was second-generation wireless, or 2G, which emerged in the early 1990s. 2G technologies were digital and offered the much-needed capacity that 1G analog systems did not afford. Several technologies were widely used:

• TDMA (IS-54 and IS-136)
• GSM (a TDMA based technology)
• CDMA IS-95 or cdmaOne (a CDMA based technology)

However, these 2G technologies are incompatible with each other. Thus, mobile service subscribers were still often limited to using their phones in a single country or region.

In an effort to standardize future digital wireless communications and make global roaming with a single handset possible, the ITU established a single standard for wireless networks in 1999. Called IMT-2000, which is commonly referred to today as 3G, the initiative set forth the requirements (mentioned above) for the third generation of wireless networks.

3G – The Standard:

3G stands for third-generation wireless technology and networks. The concept of a single standard evolved into a family of five 3G wireless standards. Of those five, the most widely accepted are CDMA2000, WCDMA (UMTS) and TD-SCDMA. According to the ITU and IMT-2000, a wireless standard must meet minimum bit-rate requirements to be considered 3G:

• 2 Mbps in fixed or in-building environments
• 384 Kbps in pedestrian or urban environments
• 144 Kbps in wide area mobile environments
• Variable data rates in large geographic area systems (satellite)

In addition to providing faster bit rates and greater capacity over previous-generation technologies, 3G standards excel by effectively:

• Delivering mobile data
• Offering greater network capacity
• Operating with existing second-generation technologies
• Enabling rich data applications such as VoIP, video telephony, mobile multimedia, interactive gaming and more

3G Today:
Today, WCDMA (Wideband CDMA) and CDMA2000 are by far the dominant standards in terms of current commercial services, operator deployment plans and vendor support. Launched commercially by wireless operators in 2000, CDMA2000 1X was the world’s first operational 3G technology, capable of transmitting data faster than most dial-up services. Today, more than 190 million people enjoy the benefits of CDMA2000 1X, which provides enhanced data capacity compared to all 2G technologies.

Also known as UMTS (Universal Mobile Telecommunications System), WCDMA (Wideband CDMA) is the 3G standard chosen by most GSM/GPRS wireless network operators wanting to evolve their systems to 3G network technology. WCDMA offers enhanced voice and data capacity and peak data rates faster than most dial-up services and average rates consistently greater than GSM/GPRS (Global System for Mobile communications/General Packet Radio Service) and EDGE (Enhanced Data for GSM Evolution). As of February 2006, more than 51 million subscribers were using WCDMA for their mobile voice and data needs.

Architecture: