Fourth generation of mobile communication

will be up to inter-operator agreements. It is possible that this might be provided dynamically for "new" network pairs and would include authentication and agreement on methods of financial settlement.

4.6.4. Human factors GSM has defined a limited set of standard Man Machine Interface requirements, generally in line with existing European (CEPT) practice. However, it is not clear that this would be acceptable in a world environment. Many aspects of Human Factors can be left to the terminal designer, but it is also desirable for some aspects to be "married" to the user, whose requirements could be stored either with his profile in the network or in his UIM. a) Charging Traditionally, charging aspects have not been defined by technical standards committees.

However, on UNITS it is likely that a mechanism will need to be standardized for secure transport of charging information when roaming. b) Evolution By the time of introduction of UMTS, the value of the installed base of GSM around the world will be many billions of ECU. By then, the functionality of GSM will have been extended towards that of UMTS, so a smooth migration path will be essential. However, successful standards need to develop and experience in GSM has shown that it is vital to be able to evolve the standard, even within a generation. Evolution would include (for example) services, frequency bands and technologies. c) Radio Access This section sets out the requirements for the Third Generation Radio Access, which the Group recommend that UK Government and industry endorse. A concluding recommendation is made for participation in the selection process for the new system. d) Service Adaptation A goal for third generation mobile systems is to provide universal coverage and to enable terminals to be capable of seamless roaming between networks, which may be of differing types. Realistically, a uniform level of service is impractical, particularly for multimedia services requiring high bandwidths. For customer premises networks and very small area cellular systems, the goal is to be able to offer communications up to 155 Mbit/s by means of 60 GHz wireless. For cellular and micro-cellular applications, the current goal for UMTS is to provide burst rates of up to 2 Mb/s. However with the finite "spectrum available in the 2 GHz region for UMTS, it is clearly impractical to offer continuous connections at such high bit rates for conventional macro-cellular and wide area systems. For the mobile satellite element, it is impossible. e) Quality of Service Aspects Quality of service, with respect to the radio interface, traditionally comprises two main attributes, low error rate and low delay. The speech coder has also been considered as part of the Radio Access system and therefore excellent speech quality has also been a key metric.

However, as the operation of cellular networks has become more sophisticated, other quality factors have also come into play, such as dynamic consistency of quality (e.g. in a fading environment), transmission breaks (e.g. due to handover), as well as factors which affect