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Much of the dynamism present in the telephony industry today has stemmed from mobile telephony. The first generation of mobile telephones were based on analogue technology and were relatively unsophisticated. The second generation systems involved digital technology. Perhaps the most successful of these is the Global System for Mobile (GSM) Communications.
Applied research is now taking place aimed at defining standards for the 3rd generation mobile systems. At a European level, this is referred to as the Universal Mobile Telecommunications Systems (UMTS) and the global standardization effort undertaken by the ITU is called IMT-2000. The direction of this research is to evolve today's circuit switched core network to support new spectrum allocations and higher bandwidth capability. Efforts are also being made to integrate the many diverse mobile environments in addition to blurring the distinction between the fixed and mobile networks.
4th generation telephony supports broadly similar goals to the 3rd generation
effort but starts with the assumption that future networks will be entirely
packet-switched using protocols evolved from those in use in today's Internet.
Today's internet telephony systems are the forerunner of the applications
that will be used in the future to deliver telephony services.
Among the major benefits of the 4th generation approach are the following:
Naming and Addressing
Users will need to identify themselves and register for services - they may do this use a range of different identities. Computability with existing systems e.g. Telephone Number (E.164), IMSI, IMUN, IP Address, E-mail address must be considered.
Directory services will be required to map from a users identity to a routable network address to which the call can be delivered. In 4th generation systems, all users will be treated as being mobile, and will thus roam from one network point on another.
In cases where users are using wireless networks to avail of services, it will be possible for users to change location while calls are active. Support must be provided to allow for handoff, and maintenance of the call state.
Quality of Service (QoS) Support
In order to deliver a quality voice stream across a packet switched network, efforts must be made to control network QoS factors such as end-to-end delay, packet loss and jitter. One technique that can address the delay issue is our Smart IP Switching.
The packet switched networks of the future will reflect the structure of today's Internet. That is, they will be made up of interconnected islands of infrastructure owned by competing commercial concerns. The architecture underlying the deliver of telephony services can be simplified using payment systems
The majority of protocols developed for MAC control on wireless links have focused on providing a circuit switched service - adaptation will be required for efficient support of 4th generation services.
Future Tense, RTÉ Radio One's weekly science show broadcast an item in 1998 about the work being carried out at the NTRG. You can download the item in three audio formats: