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内容説明 Satellite communication systems represent an important solution to integrate and to complement terrestrial systems， since satellites allow the following advantages: (i) easy fruition of both broadcast and multicast high bit-rate multimedia services; (ii) provision of backup communication services for users on a global scale; (iii) efficient support of high-mobility cellular users (e.g.， users on trains， planes， etc.); (iv) support of broadband applications and services in rural and remote areas for both fixed and mobile users. Multimedia traffic support， multicast and broadcast services are the driving forces for new satellite systems that are expected to provide services with comparable Quality of Service (QoS) levels of terrestrial systems. In particular， the interest is here on the Satellite UMTS system for mobile users and the DVB-S/DVB-S2/DVB-RCS networks for broadband fixed users. New satellite network architectures， protocol design， and adaptivity schemes are necessary to allow the support of prospected future services. Satellite resources are costly and satellite communications impose special constraints with respect to terrestrial systems in terms of channel model， attenuation， propagation delays， fading， etc. The ISO/OSI reference standard is based on a layering paradigm， a strict modularity and layer independence. Such classical approach may lead to non-optimal performance in IP-based next-generation satellite communication systems. In this framework， an optimized cross-layer approach is needed where interactions even between non-adjacent protocol layers are employed. This book provides significant knowledge on innovative radio resource management schemes for satellite communication systems that exploit lower layer adaptivity and the knowledge of layer 3 IP QoS support and transport layer behavior. This book is an interesting novelty since it integrates competencies considering all the parts of system design (i.e.， propagation aspects， radio resource management， access protocols， network protocols， transport layer protocols， etc.) to cover both broadband and mobile satellite systems. A detailed analysis of cross-layer air interface design will be provided with new simulation results， proving that such approach can permit to guarantee high QoS levels for differentiated traffic classes and high utilization of air interface resources. Two scenarios will be addressed for cross-layer optimization issues， that is the satellite version of the terrestrial UMTS for mobile users (3GPP) and the DVB-S/-S2/-RCS air interface for broadband fixed transmissions (ETSI). This book is intended as the outcome of the research results obtained during the last two years in the workpackage 2430 (SatNEx project， www.satnex.org) leaded by Dr. Giovanni Giambene - University of Sienna， Italy.