Objective
Recently ETSI-SMG5 has proposed an evolutionary approach from 2nd generation systems (e.g. Global System for Mobile communications, GSM) towards next generation systems (i.e. Universal Telecommunication Systems, UMTS, and Mobile Broadband System, MBS). Thus, starting from the specification of 2nd generation mobile communication systems, the new COST Action (originated from the previous COST 227) will investigate the smooth migration towards the satellite integration for 3rd and 4th generation global mobile systems. A feasibility study and system specification will be carried out which aim to define the main technical aspects and requirements needed for the achievement of systems such as UMTS and MBS. Two are the main objectives considered within this Action : a mid-term activity focused on the adaptability of the GSM standard (2nd generation mobile terrestrial system) to Mobile Satellite System (MSS) ; and a longer-term activity dealing with the exploitation of the satellite component for the MBS able to provide services at higher rates (> 2Mb/s) than presently assumed in the UMTS.
Current status
Method of Working
The activities of the Action (started in October 1996) have been divided into three tasks (each task corresponding to a Working Group). Each task has a number of working packages (WP), as follows :
Task 1 - Strategic Scenarios and a feasibility study
Task 2 - Network Aspects
Task 3 - Air Interface Aspects
Each Working Group carries out the activities of its own Task and regularly during the Management Committee Meetings reports on the outcomes, presenting the relevant documentation for discussion.
Description for planned Activities
The satellite system integrated with the terrestrial cellular one at the highest level will be considered as an essential feature to achieve global mobile communication systems. Geostationary and non-geostationary constellations of satellites will be addressed with major emphasis in the latter ones more suitable for hand-held terminals. The planned activities for each Task are as follows :
Task 1
WG1 - Strategic Scenarios and a feasibility study
A first important step towards the achievement of future satellite-terrestrial integrated systems is the study of a smooth migration from 2nd generation terrestrial systems (e.g. GSM) to include a satellite component. This is a key point, because it relates to the interests of both users and operators : on one hand, we have the interest of operators to save the large investments for the implementation of 2nd generation terrestrial systems ; on the other hand, we have the interests of the users to be able to reuse as much as possible their terminals even for future networks. Inputs from the COST 231 Action ("Evolution of Land Mobile Radio (including personal) Communications") will be used for the research within COST 252 Action. The strategic elements for the deployment of future integrated networks will be :
the ease of implementation of new multimedia and personalised services, Services integration into a network.
Based on the recommendations of ITU, ETSI and of the outcome of RACE, service and security requirements have to be studied.
The use of non-geostationary orbits for the satellite component of the systems (in particular, Low Earth Orbits and Medium Earth Orbits) will be considered.
It is considered essential that there should be a co-operation with COST 248 Action, titled "The Future European Telecommunications User", that studies the user's attitude on future telecommunication services and products. Related inputs on regulatory issues and system requirements are expected from other bodies and groups (e.g. ETSI, ITU-T, ITU-R, SAINT, ACTS).
Task 2
WG2 - Network Aspects
It is a matter of fact that many future global coverage Mobile Satellite Systems (MSSs) will use a constellation of non-geostationary satellites. Starting from the outputs of COST 227 Action and related RACE projects (e.g. SAINT, MBS, MONET), it is necessary to proceed with the studies to improve or modify the network architecture and add new system functionalities. Then, a further division into sub-tasks has been considered within this working group according to the following topics :
The study of the Network Architecture ;
The study of Procedures and Protocols ;
Consideration of Resources Management in the integrated terrestrial-satellite scenario.
Task 3
WG3 - Air Interface Aspects
The interest here focuses on transmissions aspects, including the characterisation of the satellite channel (especially in the case of non-geostationary satellites), and technology issues in order to cope with the link budget requirements that are particularly critical in the case of hand-held mobile terminals. Moreover, specific requirements on the technology are expected to fulfil the requirements related to RF emissions of handsets (health hazard). A close co-operation with other related COST Project is deemed to be essential (e.g. COST 244 Action, titled "Biomedical Effects of Electromagnetic Fields"). Then, the work within this group is divided among the following topics :
Characterisation of non-GEO channels and propagation effects ;
Multiple Access Techniques and Inter-System Interference ;
Identification of GSM and UMTS commonalties for a smooth transition ;
Handover strategies ; Receivers : modulation, coding and equalisation with variable data rates ;
Gateway station ;
Terminal technology including biological constraints.
WEB page
The updated status of COST252 can be found at :
http://amerigo.die.unifi.it/cost252
Programme(s)
Topic(s)
Call for proposal
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50139 Firenze
Italy