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Wireless Communications, IEEE

Issue 5 • Date Oct. 2005

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Displaying Results 1 - 21 of 21
  • IEEE Wireless Communications

    Page(s): 0_1
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  • Table of contents

    Page(s): 2
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  • Scanning the literature

    Page(s): 6 - 7
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  • Blockage mitigation techniques in satellite communications

    Page(s): 10 - 13
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (147 KB) |  | HTML iconHTML  

    This article proposes systematic approaches to minimize severe channel degradation. Detection of channel condition is performed by means of two continuous ARQ NAK counting schemes. Stop-and-wait ARQ non-NAK counting is used for timed complete blockage. A single (31,21,5) code is designed for all the ARQ systems proposed. After the blockage state of a transmission channel is determined, satellite link parameter trade-offs and other specific remedy alternatives are recommended to enhance channel performance. System performance criteria are derived with different Earth station capabilities. View full abstract»

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  • Dynamic capacity allocation for quality-of-service support in IP-based satellite networks

    Page(s): 14 - 20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (209 KB) |  | HTML iconHTML  

    In broadband satellite access networks, the efficient management of the return channel transmission capacity is key in reducing the service cost while satisfying the QoS requirements of IP-based multimedia applications. In this article a dynamic capacity allocation scheme based on combined free/demand assignment multiple access is proposed, allowing the return channel capacity to be efficiently shared among many user terminals. Simulation results indicate that the proposed scheme provides adequate DiffServ IP QoS support while maintaining high satellite bandwidth utility and reduced DCA signaling overhead. View full abstract»

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  • QoS provisioning in GEO satellite with onboard processing using predictor algorithms

    Page(s): 21 - 27
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (151 KB) |  | HTML iconHTML  

    Recently, IP satellite networks have attracted considerable interest as a technology to deliver high-bandwidth IP-based multimedia services to nationwide areas. In particular, IP satellite networks seem to be one of the most promising technologies for connecting users in rural areas, where a wired high-speed network (e.g., xDSL) is not foreseen to be used. However, one of the main problems arising here is to guarantee specific quality of service constraints in order to have good performance for each traffic class. Among various QoS approaches used in the Internet, recently the DiffServ technique has become the most promising solution, mainly for its scalability with respect to the IntServ approach. Moreover, in satellite communication systems, DiffServ computational capabilities are placed at the edge points, reducing the implementation complexity of the satellite onboard equipment. This article deals with the problem of QoS provisioning for packet traffic by considering some resource allocation schemes, including bandwidth allocation techniques and priority-driven onboard switching algorithms. As to the first aim, the proposed technique takes advantage of proper statistical traffic modeling to predict future bandwidth requests. This approach takes into consideration DiffServ-based traffic management to guarantee QoS priority among different users. Moreover, the satellite onboard switching problem has been addressed by considering a suitable implementation of the DiffServ policy based on a cellular neural network. View full abstract»

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  • Critical issues of onboard switching in DVB-S/RCS broadband satellite networks

    Page(s): 28 - 36
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    The next generation of broadband satellite networks is challenged to accommodate multimedia services while concurrently integrating with terrestrial IP networks. With IP applications dominating the Internet, carrying IP traffic over the satellite has been under intensive study. Originally developed to bring digital television home through satellites, the DVB-S and DVB-RCS standards empower interactive satellite communications with economical standardized satellite terminals. Furthermore, onboard switching technology is increasingly gaining attention, due to optimized bandwidth usage, fully meshed network topology through one satellite hop, and quality of service guarantee. This article investigates the onboard switching technologies in DVB-S/DVB-RCS broadband satellite networks. Aside from the network system infrastructure and switch hardware architecture, the QoS mechanisms supported by the switch onboard the satellite are discussed in depth. View full abstract»

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  • Call for papers

    Page(s): 37
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  • Securing multicast in DVB-RCS satellite systems

    Page(s): 38 - 45
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB) |  | HTML iconHTML  

    While TV broadcasting is probably the best known application of satellite technology, satellite service providers are now expanding their services to include Internet data transmission. Consequently, security of satellite data is becoming an important issue. This article examines the current DVB-RCS security standard and identifies the principal gaps in the provision of secure multicast over DVB-RCS. The main contribution of this article is a proposal for adapting the current DVB-RCS two-way satellite standard to provide secure multicast services over satellites. View full abstract»

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  • VoIP over DVB-RCS with QoS and bandwidth on demand

    Page(s): 46 - 53
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (173 KB) |  | HTML iconHTML  

    Motivated by the need for compliance/interoperability above the satellite-specific layers, this article proposes a consolidated approach for voice over IP over satellite networks based on the ETSI DVB-RCS standard. Voice communication is a real-time service that needs priority over other services in IP environments with limited bandwidth, such as IP satellite networks. Bandwidth utilization in such networks needs to be optimized in order to reduce service costs, and this requires the use of dynamic bandwidth allocation schemes. This article therefore addresses the role of bandwidth on demand in the optimization of bandwidth allocation for VoIP and assesses the impact of BoD mechanisms on voice quality. The trade-off between voice quality and bandwidth efficiency is investigated under different DVB-RCS-specific capacity request/allocation strategies, and it is demonstrated that DVB-RCS provides an efficient platform for integrated support for a variety of VoIP applications over satellite. The main contribution of this article consists of the identification of the mechanisms capable of responding to the key challenges raised by the VoIP application in the satellite environment. View full abstract»

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  • Evaluation of SCTP for space networks

    Page(s): 54 - 62
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    The stream control transmission protocol has recently been standardized as a new transport layer protocol in the IP protocol suite. SCFP is based on the TCP protocol, but incorporates a number of advanced and unique features that are not available in TCP. Although the suitability of TCP over satellite networks has been widely studied, the suitability of SCTP over satellite networks remains to be evaluated. The objective of this article is to investigate the suitability of SCTP for data communications over satellite networks. We focus on the advanced features of SCTP that enhance its performance in satellite networks. Finally, we provide recommendations on the use of SCTP over satellite networks. View full abstract»

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  • Recent trends in IP/NGEO satellite communication systems: transport, routing, and mobility management concerns

    Page(s): 63 - 69
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (154 KB) |  | HTML iconHTML  

    Non-geostationary (NGEO) satellite communication systems are seen as an attractive solution to realize the vision of anywhere, anytime pervasive access to the Internet. Their design and development have thus gained tremendous interest in the last few years. Commencing with a brief overview of general NGEO satellite configurations, this article next addresses the key technical difficulties in the development of NGEO IP-based satellite communications systems. The article discusses routing concerns, mobility management, and transport protocols with an emphasis on TCP performance in NGEO satellite networks. Some key innovations are presented. The recursive, explicit, and fair window adjustment (REFWA) scheme is presented as a solution to improve the efficiency and fairness of TCP in NGEO systems. An improvement to the REFWA scheme, REFWA plus, is also described to combat link errors in satellite environments. View full abstract»

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  • Integration of satellite and terrestrial systems in future multimedia communications

    Page(s): 72 - 80
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (394 KB) |  | HTML iconHTML  

    In this article we examine the role of satellite communications in future telecommunication networks and service provision. Lessons from the past indicate that satellites are successful as a result of their wide area coverage or speed to market for new services. Niche areas such as coverage of air and sea will persist, but for land masses convergence of fixed, mobile, and broadcasting will dictate that the only way forward for satellites is in an integrated format with terrestrial systems. We outline future ways forward for satellites, and discuss the research challenges and technology advances needed to facilitate this integrated approach. View full abstract»

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  • Call for papers

    Page(s): 81
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  • Demonstration with field trails of a satellite-terrestrial synergistic approach for digital multimedia broadcasting to mobile users

    Page(s): 82 - 90
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (871 KB) |  | HTML iconHTML  

    The close synergy between a satellite system and terrestrial mobile cellular networks for cost-efficient content delivery to mobile users lies at the core of the satellite digital multimedia broadcasting system concept. Having already rich research and design work behind it, much of which has been carried out in the framework of European R&D projects, the system has recently seen the end of its first field trials, which relied on an experimental platform representing the future operational system. The article reports the outcomes of these trials that confirmed the technical feasibility of the system concept and provided valuable hints for the subsequent system design stages. View full abstract»

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  • Design considerations of satellite-based vehicular broadband networks

    Page(s): 91 - 97
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    Convergence between wireless networks is the main trend in current and future wireless communications. The distinct advantage of satellite and terrestrial network integration is the possibility to provide ubiquitous multimedia services in vehicles at any location. The key design considerations of mobile broadband satellite access technologies are given in this article. After presenting the conceptual models of a system and services, the design issues of satellite network synchronization and burst demodulation are described. The design considerations of medium access control, resource management, capacity, and buffer controls for internetworking are given. Also, the active antenna issues are provided along with a sample design. View full abstract»

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  • Integrating users into the wider broadband network via high altitude platforms

    Page(s): 98 - 105
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    An overview of CAPANINA, a project funded by the European Commission's 6th Framework Programme, is presented. The project is developing communications technologies for use with aerial platforms with the aim of integrating users in hard to reach areas and those disadvantaged by geography into the wider broadband network. The article discusses the three broad areas of the project. Specific aspects covered include broadband applications and services selection, along with appropriate integrated delivery configurations to deliver the required capacity and upgradeability; and the associated trials, along with the required wireless and free space optical equipment. Longer-term research underway into delivering broadband backhaul to high-speed trains from aerial platforms, enabling integration with onboard WLAN access points, is also discussed. View full abstract»

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  • Support infrastructures based on high altitude platforms for navigation satellite systems

    Page(s): 106 - 121
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (153 KB) |  | HTML iconHTML  

    In this article the use of an augmentation system based on high altitude platforms (HAPs) for supporting global navigation satellite systems is discussed. In fact, HAP-based systems are being studied and designed for several communication applications, but they can also be considered added value infrastructure if integrated with navigation systems, providing aiding services based on terrestrial stations or geostationary satellites. The article investigates the results of a feasibility study for the design of a stratospheric pseudo-satellite to provide additional ranging signal to improve the accuracy and availability of the overall navigation system, and an effective integrity service, strengthening the reliability of the positioning procedures. The work here presented discusses issues that have arisen in the design, and provides simulation performance of the proposed architecture. View full abstract»

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Aims & Scope

IEEE Wireless Communications Magazine deals with all technical and policy issues related to personalization, location-independent communications in all media.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Hsiao-Hwa Chen
Cheng Kung University, Taiwan