9.4 UMTS Requirements and Features

UMTS requirements are driven by market needs and anticipation of new services that make it possible to create a mobile information society. The requirements can be categorized into the following primary drivers:

• Access to information and content on the Internet: As the Internet has grown, so has the dependence of its users for information, entertainment, and business. The Internet has become an integral aspect of many people's lives. Since packet data access in 2G wireless networks is limited by slow speeds and inefficient spectral use, 3G networks are expected to alleviate this problem by addressing the shortcomings and thereby enabling the creation of the wireless Internet.

• Global roaming: With the wide disparity in types of networks deployed globally, roaming across networks has become an issue. UMTS requires that a common core network be able to support different types of access networks. With this, roaming across heterogeneous access types becomes easier since the core and the protocols to access the network and services remain the same.

• New services: UMTS networks are also intended to provide new types of services in addition to traditional voice. Multimedia services such as audio and video streaming, video telephony, and integration of voice and data to provide a rich user experience are expected to be possible with these networks.

• Convergence of datacom and telecom: With wired networks moving in the direction of convergence, wireless networks are set to follow suit, and hence a network that is essentially moving in the direction of being a packet based network is another trend.

The 3G networks are feature rich. UMTS networks increase data rates in the radio interface, improve subscriber security, and clarify the functional split between the access and core networks. The achievable data rates with the new WCDMA interface can be as high as 2 Mbps in the hotspots (at pedestrian speeds) and up to 10 Mbps with HSDPA. The WCDMA technology provides flexibility in radio resource allocation. High-bit-rate users consume capacity and leave lower speeds for other users. The radio resource optimization is a complex issue, whose goal is to optimize the number of users, their access speed, and access network coverage in the best possible way. The UMTS packet core inherits many of the GPRS architectural decisions and features but moves all radio- related functionality into the access network.

From the IP networking perspective, the high access data rate alone is a huge improvement over GPRS. How the improvements are achieved ”the radio protocols and so on ”is irrelevant to IP. The bandwidth increase enables new IP services in addition to the "basic" ones GPRS can provide; real-time services like voice over IP (VoIP) and streaming video will be among the driving applications for UMTS. In order to support such real-time services, the networks will have to support quality of service (QoS).

Subscriber security improvement comes from the stronger cryptography and the two-way authentication UMTS deploys. In GSM and GPRS only the subscriber authenticates himself or herself to the network; in UMTS the network also authenticates toward the user. With the basic GSM voice service the difference is not that significant, but with monetary transactions in UMTS the subscriber really wants to be sure whose network he or she is using.

Core and service network access independence is clearly an essential enabling feature to make a session handover possible, in addition to the radio access handover in place today.