Universal Mobila Telephone Service

One of the major new third-generation (3G) mobile systems being developed within the global IMT-2000 framework is the Universal Mobile Telecommunications System (UMTS), which has been standardized by the European Telecommunications Standards Institute (ETSI). UMTS makes use of UMTS Terrestrial Radio Access (UTRA) as the basis for a global terrestrial radio access network.

Europe and Japan are implementing UTRAin the paired bands 1920–1980 MHz and 2110–2170 MHz. Europe also has decided to implement UTRA in the unpaired bands 1900–1920 MHz and 2010–2025 MHz. UMTS combines key elements of Time Division Multiple Access (TDMA)—about 80 percent of today’s digital mobile market is TDMA-based—and Code Division Multiple Access (CDMA) technologies with an integrated satellite component to deliver wideband multimedia capabilities over mobile communications networks.

The transmission rate capability of UTRAwill provide at least 144 kbps for full-mobility applications in all environments, 384 kbps for limited-mobility applications in the macro- and microcellular environments, and 2.048 Mbps for low-mobility applications particularly in the micro- and picocellular environments. The 2.048-Mbps rate also may be available for short-range or packet applications in the macrocellular environment.

Because the UMTS incorporates the best elements of TDMAand CDMA, this 3G system provides a glimpse of how future wireless networks will be deployed and what possible services may be offered within the IMT-2000 family of systems.

UMTS Objectives

UMTS makes possible a wide variety of mobile services ranging from messaging to speech, data and video communications, Internet and intranet access, and high-bit-rate communication up to 2 Mbps. As such, UMTS is expected to take mobile communications well beyond the current range of wireline and wireless telephony, providing a platform that will be ready for implementation and operation in the year 2002.

UMTS is intended to provide globally available, personalized, and high-quality mobile communication services. Its objectives include:

  • Integration of residential, office, and cellular services into a single system, requiring one user terminal.
  • Speech and service quality at least comparable to current fixed networks.
  • Service capability up to multimedia.
  • Separation of service provisioning and network operation.
  • Number portability independent of network or service provider.
  • The capacity and capability to serve over 50 percent of the population.
  • Seamless and global radio coverage and radio bearer capabilities up to 144 kbps and further to 2 Mbps.
  • Radio resource flexibility to allow for competition within a frequency band.


UMTS separates the roles of service provider, network operator, subscriber, and user. This separation of roles makes pos sible innovative new services without requiring additional network investment from service providers. Each UMTS user has a unique network-independent identification number, and several users and terminals can be associated with the same subscription, enabling one subscription and bill per household to include all members of the family as users with their own terminals.

This arrangement would give children access to various communications services under their parents’ account. This application also would be attractive for businesses that require cost-efficient system operation— from subscriber/user management down to radio system—as well as adequate subscriber control over the user services. UMTS supports the creation of a flexible service rather than standardizing the implementations of services in detail.

The provision of services is left to service providers and network operators to decide according to the market demand. The subscriber— or the user when authorized by the subscriber— selects services into individual user service profiles, either with the subscription or interactively with the terminal. UMTS supports its services with networking, broadcasting, directory, localization, and other system facilities, giving UMTS a clear competitive edge over mobile speech and restricted data services of earlier-generation networks.

Being adept at providing new services, UMTS is also competitive in the cost of speech services and as a platform for new applications. UMTS offers a high-quality radio connection that is capable of supporting several alternative speech codecs at 2 to 64 kbps, as well as image, video, and data codecs. Also supported are advanced data protocols covering a large portion of those used in Integrated Services Digital Network (ISDN). The concept includes variable and high bit rates up to 2 Mbps.

Functional Model

The UMTS functional model relies on distributed databases and processing, leaving room for service innovations without the need to alter implemented UMTS networks or existing UMTS terminals. This service-oriented model provides three main functions: management and operation of services, mobility and connection control, and network management.

  • Management and operation of services Aservice data function (SDF) handles storage and access to service-related data. Aservice control function (SCF) contains overall service and mobility control logic and service-related data processing. Aservice switching function (SSF) invokes service logic—to request routing information, for example. Acall control function (CCF) analyzes and processes service requests in addition to establishing, maintaining, and releasing calls.
  • Mobility and connection control Drawing on the contents of distributed databases, UMTS will provide for the realtime matching of user service profiles to the available network services, radio capabilities, and terminal functions. This function will handle mobile subscriber registration, authentication, location updating, handoffs, and call routing to a roaming subscriber.
  • Network management Under UMTS, the administration and processing of subscriber data, maintenance of the network, and charging, billing, and traffic statistics will remain within the traditional telecommunications management network (TMN).

TMN consists of a series of interrelated national and international standards and agreements that provide for the surveillance and control of telecommunications service provider networks on a worldwide scale. The result is the ability to achieve higher service quality, reduced costs, and faster product integration. TMN is also applicable in wireless communications, CATV networks, private overlay networks, and other large-scale, high-bandwidth communications networks.

With regard to UTMS (and other 3G wireless networks), TMN will be enhanced to accommodate new requirements. In areas such as service profile management, routing, and radio resource management between UMTS services, networks, and terminal capabilities, new TMN elements will be developed.

Bearer Services

Under UMTS, four kinds of bearer services will be provided to support virtually any current and future application:

  • Class A This bearer service offers constant-bit-rate (CBR) connections for isochronous (real-time) speech transmission. This service provides a steady supply of bandwidth to ensure the highest quality speech.
  • Class B This bearer service offers variable-bit-rate connections that are suited for bursty traffic, such as transaction-processing applications.
  • Class C This bearer service is a connection-oriented packet protocol that can be used support time-sensitive legacy data applications such as those based on IBM’s Systems Network Architecture (SNA).
  • Class D This is a connectionless packet bearer service. This is suitable for accessing data on the public Internet or private intranets.

By harnessing the best in cellular, terrestrial, and satellite wideband technology, UMTS will guarantee access to all communications, from simple voice telephony to high-speed, high-quality multimedia services. It will deliver information directly to users and provide them with access to new and innovative services and applications.

It will offer mobile personalized communications to the mass market regardless of location, network, or terminal used. Users will be provided with adaptive multimode/multiband phones or terminals with a flexible air interface to enable global roaming across locations and with backward compatibility with second-generation (2G) systems.