This paper focuses on the broadcast channel of an interactive Multibeam Broadband Satellite (MBS) system with a transparent architecture. In particular, a cross-layer design is proposed for the packet scheduling on a ...
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This paper focuses on the broadcast channel of an interactive Multibeam Broadband Satellite (MBS) system with a transparent architecture. In particular, a cross-layer design is proposed for the packet scheduling on a forward link that implements adaptive coding and modulation (ACM). A crosslayer approach is considered whereby the physical and Medium Access Control (MAC) layers share knowledge of the channel dynamics in presence of ACM. Transmission power and symbol rate are assumed to be constant, and hence the bit rate is time and space dependant according to the channel conditions. An architecture is proposed which relies on the physical characteristics of the Ka-band satellite propagation channel and the definition of "correlated areas". The stable throughput region has been derived assuming full-queue traffic conditions. Moreover, the proposed architecture is simple but flexible enough to allow the implementation of different scheduling policies like the proportionally fair or opportunistic ones. Finally, a new time-fair policy appropriate for wet seasons is proposed. It has the property of isolating users in clear-sky conditions from the effects of the reduced transmission rate experienced by users under a rain fade.
Blind decoding, used on control channels of some multi-user wireless access systems, is a technique for achieving adaptivemodulation and coding. The idea is to adapt the modulation and coding scheme to the channel qu...
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ISBN:
(纸本)9781467309202
Blind decoding, used on control channels of some multi-user wireless access systems, is a technique for achieving adaptivemodulation and coding. The idea is to adapt the modulation and coding scheme to the channel quality but instead of signaling the parameters used explicitly, the receiver blindly tries a number of fixed parameter combinations until a successful decoding attempt is detected, with the help of a cyclic redundancy check. In this paper we suggest a new method for reducing the complexity and energy consumption associated with such blind decoding schemes. Our idea is to use a mini-CRC injected early in the data stream to determine if the current decoding attempt is using the correct modulation and coding parameters. We analyze and exemplify the complexity gain of this approach and also investigate the impact of the rearrangement of the CRC scheme in terms of the probability of undetected error. The presented results for the complexity gain are promising and the impact on the error detection capability turns out to be small if any.
The conventional wireless communication systems are designed to overcome the worst-case channel, using the huge amount of redundant bits to assure communications performance and quality of services. Those systems cann...
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The conventional wireless communication systems are designed to overcome the worst-case channel, using the huge amount of redundant bits to assure communications performance and quality of services. Those systems cannot achieve the optimum spectrum and power efficiency. This paper presents an adaptive coding and modulation scheme used in the user terminals of the third-generation satellite communication system. A three-state photogrammetric channel estimation method is introduced for tracing the variations of large-scale environments. The mobile user terminal dynamically switches the suitable coding and modulation schemes according to the result of photogrammetric channel estimator in order to maximize the power efficiency and data throughput. The real measurement data were used to validate our proposed method. The results show that the proposed method not only reduces the system complexity, but also mitigates the power control requirements and increases the data throughput for the land mobile satellite personal communication systems. Copyright (c) 2006 John Wiley & Sons, Ltd.
d In this paper an analysis on the use of adaptive coding and modulation (ACM) techniques for EHF satellite communications is presented. In particular, our analysis is focused on W-band channels and includes the main ...
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ISBN:
(纸本)9781424456383
d In this paper an analysis on the use of adaptive coding and modulation (ACM) techniques for EHF satellite communications is presented. In particular, our analysis is focused on W-band channels and includes the main channel impairments in this frequency band, i.e. rain fading and HPA non-linearity. The aim of the analysis is to identify modifications to the ACM mode switching algorithm to optimize their use at those high frequency bands.
Convergence of broadcasting, communications and related domains is intensified recently. IP has become the key “convergence layer”, while adaptive coding and modulation was adopted by most recent physical layer reco...
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Convergence of broadcasting, communications and related domains is intensified recently. IP has become the key “convergence layer”, while adaptive coding and modulation was adopted by most recent physical layer recommendations. GSE scheduler is just needed by DVB systems to arrange IP packets into physical layer containers, which is of variable length. This paper introduces a novel scheduler of GSE over DVB-S2. The scheduler is studied by both theoretical analysis and simulation. The research reveals that the novel scheduler makes significant improvement on the system performance.
A tool has been designed to simulate broadband satellite communication systems and techniques: a system and protocol simulator based on advanced DVB-RCS and DVB-S2 standards. As it powerful and flexible tool, it can b...
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ISBN:
(纸本)9781424425723
A tool has been designed to simulate broadband satellite communication systems and techniques: a system and protocol simulator based on advanced DVB-RCS and DVB-S2 standards. As it powerful and flexible tool, it can be used to investigate and optimize current and future satellite communication systems, mainly to develop resource management algorithms and assess system performances. It is capable of simulating a satellite system using Ka-Band with mufti-beam European coverage. It integrates rain attenuation and interference models and respects the complete DVB-RCS/DVB-S2 protocol stack and an evolution of DVB-RCS with adaptive coding and modulation (ACM). The simulator supports different Quality of Services (QoS)/Service Level Agreements (SLA), ACM, several encapsulation schemes, congestion control mechanisms, call admission control and resource management. This paper gives an overview of the possibilities offered by the tool and presents some results.
Satellite Digital Video Broadcasting is deeply changing : the next generation is dedicated to packet based communications and introduces (like many modern physical layers : WiMax, HSDPA, ...) fade mitigation technique...
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ISBN:
(纸本)9781424423248
Satellite Digital Video Broadcasting is deeply changing : the next generation is dedicated to packet based communications and introduces (like many modern physical layers : WiMax, HSDPA, ...) fade mitigation techniques leading to variable throughput. Such tremendous changes need to be taken into account and introduce the need for a scheduling entity. This paper investigates the opportunity to implement classical scheduler techniques tailored to suit fade mitigation techniques. With the help of a dedicated encapsulation scheme allowing fragmentation and concatenation, we show that stability can be achieved even at high load with basic algorithms. We then show that reclassification (an opportunity that can be described as a side effect of fade mitigation techniques) induces a significant improvement on the system performance.
The paper gives an overview of the UNIC project and describes the DVB-S2 ACM (adaptive coding and modulation) and ACM/QoS (Quality of Service) test platform developed by the project, to optimize satellite access perfo...
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ISBN:
(纸本)9781424425723
The paper gives an overview of the UNIC project and describes the DVB-S2 ACM (adaptive coding and modulation) and ACM/QoS (Quality of Service) test platform developed by the project, to optimize satellite access performance in a TV centric 2-way satellite scenario with interactive multimedia offer to the users. The ACM and ACM/QoS requirements, the development activities and summary of the results of the tests carried out during the project laboratory and field trials is also given.
This paper proposes a methodology for designing and optimizing the performance of adaptive coding and modulation (ACM) schemes for the forward link of unicast satellite broadband networks. The proposed technique of ge...
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This paper proposes a methodology for designing and optimizing the performance of adaptive coding and modulation (ACM) schemes for the forward link of unicast satellite broadband networks. The proposed technique of general applicability is based on the overall system capacity maximization conditioned on meeting a certain service area coverage for a given outage probability. The paper first derives in detail the method for computing the Shannon-based capacity of a multi-beam satellite system adopting ACM. Then the link efficiency is optimized under different physical layer constraints allowing a more realistic system performance assessment. Finally, to exemplify the methodology application and to quantify the ACM system performance improvement capabilities a study case corresponding to a Ka-band state-of-the-art bent pipe satellite network is provided. The example illustrates the very substantial capacity gain offered by state-of-the-art adaptivemodulation and coding schemes utilization compared to current broadband satellite system design approach. Copyright (C) 2004 John Wiley Sons, Ltd.
The paper discusses cross-layer issues of DVB-S2 networks with adaptive coding and modulation (ACM) on the physical layer forward link. Also future return channel via satellite (RCS) systems employing adaptive schemes...
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The paper discusses cross-layer issues of DVB-S2 networks with adaptive coding and modulation (ACM) on the physical layer forward link. Also future return channel via satellite (RCS) systems employing adaptive schemes on the return link are analysed. Cross-layer issues focus on medium access control (MAC) and encapsulation layer effects. Recent work of the S2 encapsulation over generic streams (GS) is described, and the effects on quality of service (QoS) scheduling for the forward link are analysed by means of simulation. A performance comparison between DVB-S and S2, both for transport streams (TS) and GS shows a significant gain by new encapsulation and fragmentation protocols that allow fragmentation across BBFrames. Here, realistic traffic scenarios with a mix of several services as well as rain fading are taken into account. For the return link, an adaptive scheme is discussed, going beyond the current RCS standard. Several approaches for access burst structures are presented and their impact on link efficiency through padding and encapsulation overhead is simulated. Finally, burst segmentation impact on jitter is investigated. Copyright (c) 2006 John Wiley & Sons, Ltd.
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