SUMMARYTo provide high-speed multimedia services using the digital video broadcasting-return channel satellite (DVB-RCS) standard, it is imperative to efficiently assign timeslots according to user demands and dynamically take into account the variations of the propagation conditions. In satellite networks operating above 10 GHz, rain fading constitutes the dominant factor deteriorating the quality of service. In this paper, a novel two-phase resource allocation scheme for a DVB-RCS compliant satellite network is proposed. The scheme operates in two phases, the resource calculation and the resource assignment. In the resource calculation phase, based on a dynamic channel model, an efficient algorithm is presented to determine the superframe design that maximizes system throughput. In the resource assignment phase, a novel Hybrid Bin-packing algorithm is introduced maximizing the utilization of the multi-frequency time division multiple access frame. The proposed algorithm has been compared with existing schemes exhibiting significantly better results with regard to overall system throughput.

The high-frequency segment (10-66 GHz) of the IEEE 802.16 standard seems promising for the implementation of wireless backhaul networks carrying large volumes of Internet traffic. In contrast to wireline backbone networks, where channel errors seldom occur, the TCP protocol in IEEE 802.16 Worldwide Interoperability for Microwave Access networks is conditioned exclusively by wireless channel impairments rather than by congestion. This renders a cross-layer design approach between the transport and physical layers more appropriate during fading periods. In this paper, an adaptive coding and modulation (ACM) scheme for TCP throughput maximization is presented. In the current approach, Internet traffic is modulated and coded employing an adaptive scheme that is mathematically equivalent to the replicator dynamics model. The stability of the proposed ACM scheme is proven, and the dependence of the speed of convergence on various physical-layer parameters is investigated. It is also shown that convergence to the strategy that maximizes TCP throughput may be further accelerated by increasing the amount of information from the physical layer.

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Resource allocation and call admission control (CAC) are two key issues in satellite networks for multimedia applications with quality of service (QoS) guarantees. This paper introduces a new priority-based CAC scheme for multiclass services in satellite networks operating above 10 GHz, where the dominant factor limiting performance is rain attenuation, a phenomenon exhibiting both spatial and temporal variation. The proposed scheme exploits the predictability of the satellite channel and accepts a new call if sufficient resources exist for existing and new users to guarantee their QoS requirements. At the same time, it assigns higher priority to real-time users compared to non-real time ones. The performance of the proposed scheme is investigated using Markov chain to represent the satellite channel states. Analytical expressions concerning the call blocking probability under clear sky and rain conditions are derived.