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Proceedings of the IEEE

Issue 7 • Date Jul 1990

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Displaying Results 1 - 22 of 22
  • VSAT technology, trends, and applications

    Publication Year: 1990 , Page(s): 1087 - 1095
    Cited by:  Papers (12)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    A survey of very small aperture terminal (VSAT) technology is provided, and systems and services using VSAT technology are described. Trends in VSAT technology and applications, the three general categories of VSAT networks (broadcast, point-to-point, and interactive), and system architecture and design are discussed View full abstract»

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  • Communication protocol standards for space data systems

    Publication Year: 1990 , Page(s): 1295 - 1303
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (780 KB)  

    The main elements and requirements of advanced space data networks are identified. The communication protocol standards for use on space missions during the coming decades are described. In particular, the blending of high-performance space-unique data transmission techniques with off-the-shelf open systems interconnection (OSI) protocols is described View full abstract»

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  • VSAT data networks

    Publication Year: 1990 , Page(s): 1267 - 1274
    Cited by:  Papers (18)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    The use of satellite channels for very small-aperture terminal (VSAT) data networks such as spread spectrum and ALOHA is reviewed. Certain basic aspects of the architecture of VSAT data networks are discussed. Although spread spectrum and ALOHA have different origins and are sometimes represented as competing technologies, they can in fact be characterized as different ways of viewing the same low-dimensional signals in a high-dimensional signal space. After a brief introduction to the architecture of VSAT networks, it is shown how a simple linear transformation of conventional ALOHA packets called spread ALOHA leads to signals identical in all respects to the most common form of spread-spectrum signals. Two practical consequences of this theoretical result are discussed. First, for the case of small earth stations it is not possible to find an Access technique with a higher throughput than spread ALOHA. Second, the use of different spreading sequences for different users in a packet network using spread spectrum is not necessary for user separation View full abstract»

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  • Satellite communications systems and technology, circa 2000

    Publication Year: 1990 , Page(s): 1039 - 1056
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3648 KB)  

    The authors discuss many satellite communications systems and technology concepts that can be expected by the year 2000. Challenges and changes that are taking place in the commercial market place are discussed. Technology advances that promise to enable future communications satellites to capture their share of the future marketplace are discussed. Current, near-term, and far-term technologies are discussed View full abstract»

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  • Radio determination satellite service

    Publication Year: 1990 , Page(s): 1096 - 1106
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (612 KB)  

    The capabilities and measured performance of a geosynchronous satellite-based service called the radio determination satellite service (RDSS), which operates at radio frequencies allocated by the International Telecommunications Union (ITU) and is licensed in the United States by the Federal Communications Commission (FCC), are discussed. Plans for both improvement in capability and expansion to nearly global coverage are described. Since RDSS can also provide radio navigation, some comparisons of this service with the Global Positioning System (GPS) are made View full abstract»

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  • The role of technology in influencing future civil communications satellites

    Publication Year: 1990 , Page(s): 1190 - 1205
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2304 KB)  

    Technology, both as an enabler and as a driver of new and improved communication satellites, is discussed. A brief look at the beginnings and evolution of satellite communications is given to reveal the continuing influence of technology over the past 25 years. An assessment of the current state of the art which serves as a benchmark representing how far technology has come and as a basis for comparison for future possibilities is presented. A short tutorial on communications satellite basics is presented, followed by an assessment of technologies used for satellite antennas and signal amplification and routing. A discussion of future service requirements follows, and emerging technologies are identified along with possible improved communications capabilities that can result from them. The outlook for the role of technology for future communication satellites is summarized View full abstract»

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  • NASA's advanced tracking and data relay satellite system for the years 2000 and beyond

    Publication Year: 1990 , Page(s): 1141 - 1151
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB)  

    An advanced tracking and data relay satellite system (ATDRSS) reference architecture that embodies many of the system features and technological enhancements considered essential is presented and described. The architectural and user service features of the existing TDRSS are reviewed, and certain evolutionary features that will take place by the mid-1990s are discussed. NASA's projected user service requirements for the first decade at the next century, which are the principal drivers for the ATDRSS architecture, are described, including such aspects as the real-time data rates and the quantity of simultaneous services that must be supported. The discussion of the ATDRSS reference architecture covers rationale, technology considerations, and key features of the future ATDRSS user service. A status summary of the ATDRSS program is given View full abstract»

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  • Modulation and coding for satellite and space communications

    Publication Year: 1990 , Page(s): 1250 - 1266
    Cited by:  Papers (8)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1308 KB)  

    Several modulation and coding advances supported by NASA are summarized. To support long-constraint-length convolutional code, a VLSI maximum-likelihood decoder, utilizing parallel processing techniques, which is being developed to decode convolutional codes of constraint length 15 and a code rate as low as 1/6 is discussed. A VLSI high-speed 8-b Reed-Solomon decoder which is being developed for advanced tracking and data relay satellite (ATDRS) applications is discussed. A 300-Mb/s modem with continuous phase modulation (CPM) and codings which is being developed for ATDRS is discussed. Trellis-coded modulation (TCM) techniques are discussed for satellite-based mobile communication applications View full abstract»

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  • Source coding of speech and video signals

    Publication Year: 1990 , Page(s): 1233 - 1249
    Cited by:  Papers (5)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1460 KB)  

    Some digital source coding techniques for speech and video are reviewed. Predictive coding of speech, multipulse and code-excited coders and frequency-domain coders are discussed and compared for the coding of speech signals, and intraframe and still image coding and interframe coding are examined for the coding of image and video signals. The emphasis is on those algorithms that offer high compression while maintaining the perceptual quality of the source signals are discussed. Some algorithms that are general waveform coding algorithms and do not strictly depend on the input source are included View full abstract»

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  • Management and control of CCSDS cross-support services

    Publication Year: 1990 , Page(s): 1304 - 1310
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    A candidate architecture for management and control of Consultative Committee for Space Data Systems (CCSDS) services is presented. An operations concept is presented. Candidate management procedures and a management information base for the resources to be managed are suggested. This architecture is based on concepts of network management of computer and telecommunication networks which are under study by other international standards bodies such as the International Organization for Standardization (ISO) and the International Telephone and Telegraph Consultative Committee (CCITT) View full abstract»

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  • Propagation considerations in satellite communication systems

    Publication Year: 1990 , Page(s): 1275 - 1282
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (640 KB)  

    Radiowave propagation phenomena that affect the performance of satellite communication systems are concisely discussed to introduce some topics in propagation research related to satellite systems design and to illustrate related problems and uncertainties. The focus is on tropospheric effects. A summary of relevant propagation impairments is supplied, and general classes of impairments, the physical cause of each, and the major importance of each for satellite systems are given. Some impairments in the table are critically important for certain systems applications. For example attenuation due to rainfall can be substantial for significant percentages of the time on 30/20 GHz propagation paths and will be the dominant path impairment for most Ka-band systems. Appropriate literature sources are referenced for the additional details that will be required for many applications View full abstract»

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  • INTELSAT VII: a flexible spacecraft for the 1990s and beyond

    Publication Year: 1990 , Page(s): 1057 - 1074
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1224 KB)  

    An overview of the INTELSAT VII spacecraft program is presented. The overview begins at the spacecraft definition stage with an outline of the key mission objectives. A description of the spacecraft, with particular emphasis on the payload equipment and capabilities, is provided. Key features of the competitive selection process are highlighted. Current and future innovations in the program and measures being adopted to ensure the reliability and usefulness of the spacecraft over orbital lifetimes of up to 15 years or more are discussed View full abstract»

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  • On-board switching and processing

    Publication Year: 1990 , Page(s): 1206 - 1213
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (748 KB)  

    Findings from NASA's space electronics division's (SED's) advanced systems studies related to future communications satellite services that will require onboard switching and processing technology are reviewed. SED's digital signal switching and processing technology program is reviewed. This program responds to specific systems technology development needs for enabling commercial development of future satellite services. The technologies include: modulators, demodulators, and forward error-correction hardware for space- and ground-based applications; onboard information switching and processing, onboard network control, and health monitoring; and cost-efficient ground terminals. The in-house systems integration, test, and evaluation (SITE) project, which includes a laboratory testbed for evaluating technology in a simulated systems environment, is reviewed View full abstract»

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  • Satellite direct broadcast

    Publication Year: 1990 , Page(s): 1116 - 1140
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1780 KB)  

    A brief history and commentary on the development of satellite direct broadcast (direct broadcast satellite, or DBS) to small user terminals is given, and the interrelations among the technical, economic, and political aspects are discussed. The fundamental technical problems in the transmission of video and audio directly to small user terminals are reviewed at a basic level, and points of particular interest relating to DBS are highlighted. The effects of improved transmission systems using multiplexed analog components and of high-definition television are related to the satellite transmission problems. The conflicting requirements of performance, compatibility with existing equipment, competition with other means of transmission, and vested political interests are pointed out. A reasonably complete summary of existing programs, both true DBS and near DBS, is given View full abstract»

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  • Advances in multibeam communications satellite antennas

    Publication Year: 1990 , Page(s): 1214 - 1232
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1456 KB)  

    The evolution of satellite antennas over the past quarter of a century is presented. Five major areas of advances in communications satellite antenna technology are reviewed: single offset reflectors with feed arrays, shaped reflector systems, active phased arrays, phased-array-fed dual reflector systems, and lightweight feed elements. Examples are given of existing systems and of the ongoing development of new technologies View full abstract»

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  • Operation of higher layer data communication protocols over satellite links

    Publication Year: 1990 , Page(s): 1289 - 1294
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    The International Standards Organization's (ISO's) seven-layer reference model for computer communication protocols is discussed. The layering arises out of the stratification of functions across the layers. The various protocol functions performed at each higher layer are examined in detail, identifying the appropriate procedures that affect the efficient operation of these protocols over satellite links for different ranges of transmission speeds and bit error rates. Appropriate modifications are presented for removing the possible degradation and improving the performance. Specifically, changes are discussed in Transport Protocol Class 4 (ISO 8073), Session Protocol (ISO 8327), and the File Transfer Access, and Management (FTAM) Protocol (ISO 8571) View full abstract»

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  • Land mobile satellite systems

    Publication Year: 1990 , Page(s): 1107 - 1115
    Cited by:  Papers (16)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (676 KB)  

    The general advantages and potential operating characteristics of the mobile satellite service (MSS) are described, and distinctions are made between radio telephone, which is interconnected to the public switched telephone network, and private mobile radio systems. Mobile satellite service offers voice, data, position location, and paging services, interconnection to the public switched telephone network, and the possibility of private networks. Performance and cost characteristics are given along with summaries of market needs and market demands. The space and ground systems of the MSS are described View full abstract»

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  • Fixed satellite service frequency allocations and orbit assignment procedures for commercial satellite systems

    Publication Year: 1990 , Page(s): 1283 - 1288
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (596 KB)  

    The international regulatory framework which resulted form the 1988 International Telecommunication Union (ITU) Conference on Space Services (ORB-88) and its potential effect on the implementation of US satellite systems are discussed. The impact of several significant results of ORB-88 on the ability of the FCC to assign geostationary satellite orbital positions within the US and to secure international protection for these assignments is reviewed. A table of fixed satellite service frequency allocations in North, Central, and South America is given View full abstract»

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  • Domestic and regional satellite systems

    Publication Year: 1990 , Page(s): 1075 - 1086
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1548 KB)  

    The technical characteristics of domestic and regional satellite systems are discussed. Spacecraft technology is reviewed, communication payload technology developments are discussed, and resources and economics are considered. It is seen that, compared to the installation of terrestrial microwave or optical cable networks in remote and harsh areas, satellite systems offer both lower costs and shorter time to bring on line. Proven technology and mature hardware is available for regions where orbit/spectrum space is still plentiful. As in North America, the sequence of growth is likely to be C-band and then K -band. Corresponding earth station advances in efficient modulation techniques and time-division multiple access will increase the capacity per transponder channel, while frequency and spatial reuse will provide more channels per satellite View full abstract»

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  • Architectural trends in military satellite communications systems

    Publication Year: 1990 , Page(s): 1176 - 1189
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1048 KB)  

    A historical overview of military communications by satellites and a detailed description of current systems are provided. The capabilities of present systems are reviewed in relation to user requirements and threats. It is concluded that use of satellite communications by a large number of small-terminal users (aircraft, ships, submarines, and land mobiles) still requires major technological innovations to meet needs for a substantial increase in system capacity and performance improvements in a jamming environment. The next-generation systems of the 1990s are reviewed with emphasis placed on the discussion of extremely-high-frequency (EHF) systems. Architectural trends are investigated for the post-2000 era. Alternative directions for future systems development, such as the use of highly proliferated satellite constellations, are explored View full abstract»

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  • Advanced communications technology satellite (ACTS) and potential system applications

    Publication Year: 1990 , Page(s): 1165 - 1175
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    A description of the advanced communications technology satellite (ACTS) system is given with special emphasis on the communication characteristics. Potential satellite communications scenarios, including future operational ACTS-like satellite systems, are discussed. The description of the ACTS system updates previously published ACTS system references. Detailed information on items such as experimental ground stations is presented. The potential services can be generically described as voice, video, and data services. The implementation of these services on future operational ACTS-like systems can lead to unique quality, flexibility, and capacity characteristics at lower service costs. The specific service applications that could be supported range from low to high data rates and include both domestic and international applications View full abstract»

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  • The European data relay system: present concept and future evolution

    Publication Year: 1990 , Page(s): 1152 - 1164
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (872 KB)  

    After briefly reviewing the users' requirements and the results of traffic scenario simulations needed to size the system, the design of the European data relay system (DRS) (ground and space segment) is presented in detail. The interrelationship with the other data relay systems (NASA's tracking and data relay satellite system (TDRSS) And the Japanese data relay and tracking satellite system (DRTSS)) is discussed together with the current status of systems interoperability. The evolution of DRS into a second generation, foreseen for operation at the beginning of next century, is outlined in terms of user scenario, improved spacecraft and system configurations, and technology developments needed View full abstract»

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