The TOMAS satellite-UMTS inter-trial platform

Within this paper the inter-trial platform for mobile satellite services realized in the EU-ACTS project TOMAS is introduced. The main objective of TOMAS (inter-trial testbed of mobile applications for satellite communications) is to continuously enhance the platform with state-of-the-art S-UMTS system components and to evaluate the performance in joint trials with other ACTS and non-ACTS projects. The paper gives an overview of the TOMAS S-UMTS platform architecture comprising the mobile multimedia user terminal (UT), the mobile satellite terminal (MST), the geostationary space segments used and the fixed ground segment. Particular emphasis within this paper is put on the multimedia and satellite terminals as well as on the UMTS adaptation realized in TOMAS. The results of the first MPEG-4 and H.324 real time multimedia transmission trials via satellite are also described