UMTS services

The best known new feature of UMTS is higher user bit rates: on circuit-switched con-nections 384 kbps, and on packet-switched connections up to 2 Mbps, can be reached. Higher bit rates naturally facilitate some new services, such as video telephony and quick downloading of data. If there is to be a killer application, it is most likely to be quick access to information and its filtering appropriate to the location of a user. Often the requested information is on the Internet, which calls for effective handling of TCP/UDP/IP traffic in the UMTS network. At the start of the UMTS era almost all traffic will be voice, but later the share of data will increase. It is, however, difficult to predict the pace at which the share of data will start to dominate the overall traffic volume. At the same time that transition from voice to data occurs, traffic will move from circuit-switched connections to packet-switched connections. At the start of UMTS service not all of the Quality of Service (QoS) functions will be implemented, and therefore delay-critical applications such as speech and video telephony will be carried on circuit-switched bearers. Later, it will be possible to support delay-critical services as packet data with QoS functions.