Universal Mobile Telecommunications System (UMTS) is a voice and high-speed data technology that is part of the International Telecommunication Union’s (ITU) IMT-2000 family of third-generation (3G) wireless standards. Wideband CDMA (WCDMA) is the radio technology used in UMTS. As a result, the terms UMTS and WCDMA are often used interchangeably. UMTS is based on Internet Protocol (IP) technology with user achievable peak data rates of 350 kbps and more typical speeds for both the uplink and the downlink at 200 to 300 kbps.
UMTS has garnered the overwhelming majority of new 3G spectrum licenses. Compared to emerging wireless technologies, UMTS technology is more mature and benefits from research and development that began in the early 1990s. It has been thoroughly trialed, tested and commercially deployed. UMTS deployment offers stable network infrastructures and attractive, reliable mobile devices that have rich capabilities. With the addition of HSPA for high-speed packet data services, UMTS-HSPA is quickly emerging as the dominant global mobile-broadband network.
UMTS employs a wideband CDMA radio-access technology. The primary benefits of UMTS include high spectral efficiency for voice and data, simultaneous voice and data capability for users, high user densities that can be supported with low infrastructure costs, support for high-bandwidth data applications, and a clean migration to VoIP in the future. Operators can also use their entire available spectrum for both voice and high-speed data services.
4G Americas is just one of the many industry groups to endorse UMTS technology; others include the Association of Radio Industries and Businesses (ARIB) in Japan, European Telecommunications Standards Institute (ETSI), Global mobile Suppliers Association (GSA), GSM Association (GSMA), International Telecommunication Union (ITU), 3rd Generation Partnership Project (3GPP) and UMTS Forum.
UMTS builds on GSM, which is the world’s most widely used wireless technology. UMTS enjoys a global cost structure, equipment selection and user adoption that is unmatched by any other 3G technology.
UMTS has been in commercial service in Japan since 2001 and is now available on every continent. On July 20, 2004, AT&T Wireless (U.S.) became the first operator to launch commercial UMTS service in the Western Hemisphere.
UMTS works in a variety of spectrum bands offering operators more flexibility and is currently available worldwide for use in the 450, 700, 850, 900, 1700, 1800, 1900, 2100 and 2600 MHz bands. Currently, UMTS TDD equipment is available for the 450 MHz spectrum band. Because signals travel farther at lower frequencies, UMTS networks at 850 or 900 MHz are a good fit for covering sparsely populated rural areas.
UMTS operators can use a common core network that supports multiple radio-access networks, including GSM, EDGE, WCDMA, HSPA and evolutions of these technologies. This is called the UMTS multi-radio network and it gives operators maximum flexibility in providing different services across their coverage areas.
Initial UMTS network deployments were based on 3GPP Release 99 specifications, which included voice and data capabilities. Since then, Release 5 has defined HSDPA and Release 6 has defined HSUPA. With HSPA-capable devices, the network uses HSPA (HSDPA/HSUPA) for data. Operators with Release 99 networks are upgrading them to Release 5 or Release 6.
In UMTS Release 99, the maximum theoretical downlink rate is just over 2 Mbps. Although exact throughput depends on the channel sizes the operator chooses to make available, the capabilities of devices, and the number of users active in the network limit, the peak throughput rate a user can expect to achieve is about 350 kbps in commercial networks.