bluuebunny/crossref_metadata_2025_split huggingface dataset:
Demand assignment for light‐route TDMA
Authors: Kamal S. S. , Matyas R. , Lyons R. G. 
Published: July 2007

AbstractWith the fluctuating inter‐nodal traffic levels that characterize light‐route networks, demand assignment (DA) provides the means of increasing the system's effective capacity. This paper focuses on the application of DA in light‐route TDMA, and proposes a control architecture that is well‐suited to service of heterogeneous traffic. The major advantage of the proposed architecture is its benefit from both the efficient resource management typical of centralized schemes, and the shorter response times of distributed schemes. The impact of the assignment algorithm on the grade of service to heterogeneous populations, and the difficulty in quantifying this impact are also addressed. Results from analytical and simulation models illustrating resource utilization are presented.
The smoothed step‐track antenna controller
Authors: Edwards D. J. , Terrell P. M. 
Published: July 2007

AbstractThe paper describes a new adaptive tracking system which, unlike simple step‐track sytems, does not use the stepping cycles to directly position the antenna. The system can cope with severe noise; about 15 dB worse than step track. The system is cheap and practical. Results are given for both large and small dish antennas.
Proposed novel technique for the measurement of antenna gain in satellite earth‐stations
Authors: Daly P. , Tits D. 
Published: July 2007

AbstractIn the design of communication satellite systems, knowledge of earth‐station receive antenna gain and gain stability is essential. Gain measurement relies on the establishment of a constant receive signal flux.This paper attempts to show how a standard gain horn and a reference source can be used together with a closed‐loop satellite ALC circuit to provide a stable, known received flux at the input of the earth‐station antenna with unknown gain. Theoretical limitations of the technique are discussed as a forerunner to future practical measurements.Elements of the reference receive chain are transportable and can therefore be used to cross‐calibrate antennas, even in the case of receive‐only terminals.
Inmarsat expands its horizons
Authors: Lundberg Olof 
Published: July 2007

AbstractThe International Maritime Satellite Organization (INMARSAT) is the world's only commercial satellite system providing mobile communications. This article describes the system and the services which are provided through it to the worldwide shipping and offshore industries. It provides some background on the establishment of the system and why maritime nations looked to satellites as the way to effect a dramatic improvement in maritime communications. The article discusses some of the research and development now being carried out which is expected to lead to the provision of new services, including aeronautical communications via satellite. Also mentioned is the role to be played by INMARSAT in the Future Global Maritime Distress and Safety System, now being developed by the International Maritime Organization for introduction in 1990. New services, such as these, and greatly expanded capacity are to be provided by INMARSAT in its second generation system, consisting of a new series of satellites for launch from 1988.
Viterbi decoding for impulsive interference satellite channels
Authors: Tsai Chee , Kurz Ludwik 
Published: July 2007

AbstractData taken from real satellite channels point to the fact that such non‐Gaussian behaviour as burst noise exists. Since the probability density function (p.d.f.) which minimizes the Fisher information (If) subject to the given variance of noise is Gaussian, performance can be improved by taking into account the non‐Gaussian nature of the actual noise p.d.f. To achieve the higher efficiency, a modem, which consists of a maximum likelihood sequence detector (MLSD) implemented by an adaptive Viterbi algorithm (VA), is introduced in this paper. The new form of the algorithm, based on the m‐interval polynomial approximation (MIPA) method, which adjusts the operation of the VA decoder to ensure its robustness to changing and/or non‐Gaussian noise conditions, leads to an improvement of the error probability in operation of the receiver. In contrast to coding techniques, this improvement through digital signal processing is not obtained at the expense of bandwidth expansion. Monte Carlo simulation results involving bit error rate (BER) support theoretical conclusions.
An introduction to testing techniques in the intelsat TDMA/DSI system. Part 3: Specialized test equipment for ssog tests
Authors: Colby R. J. , Parthasarathy R. , Prouse D. W. 
Published: July 2007

AbstractThis is the third paper in a four‐part series addressing the testing and alignment techniques to be used in the INTELSAT TDMA/DSI system. In the first part,1 the salient characteristics of the overall TDMA/DSI system were presented together with a discussion of the fundamental requirements for testing and alignment. In the second part,2 INTELSAT's satellite system operations guide (SSOG) for TDMA was introduced, the principles of SSOG testing were discussed and the need for several types of specialized test equipment identified. This third part reviews the features of TDMA which affect test equipment design and gives a detailed description of the three items of specialized test equipment which are essential requirements for the conduct of system tests and line‐up of individual links. The fourth part will complete the series with a report on operational experience gained in the initial stages of TDMA implementation within the INTELSAT system.
CPM—an efficient constant amplitude modulation scheme
Authors: Aulin Tor , Sundberg Carl‐Erik 
Published: July 2007

AbstractThere is an increasing demand for digitial radio transmission. The cost of a channel is proportional to the bandwidth. For many applications power is limited. For satellite applications constant amplitude modulation is advantageous because of non‐linear amplification. In this paper a class of power and bandwidth efficient constant amplitude continuous phase modulation (CPM) schemes is presented. The signals are analysed in great detail and the tools for both error probability analysis and power spectral calculations are presented. Numerical data for raised cosine (RC) pulse shaping is presented. This paper is basically an overview with new results on the trellis description of CPM. The transmission is assumed to be ideally coherent over the Gaussian channel. In a following paper we will deal with transmission imperfections such as bandlimitation and hard limiting and their effect on CPM1.
A rain attenuation model for satellite link attenuation predictions incorporating the spatial inhomogeneity of rainrate
Authors: Manning Robert M. 
Published: July 2007

AbstractA model describing the spatial inhomogeneity of rainrate within a rain cell is derived and incorporated into a specific attenuation model to yield a more exact relationship than has been used heretofore relating rainrate and the attendant attenuation at frequencies above 10 GHz. The resulting unified attenuation model relates terrestrial and slant path attenuation, effective propagation distance and path diversity gain to parameters characterizing the earth‐station or stations (e.g. location, height, latitude, elevation angle and baseline distance from another station), the frequency of operation, and the two possible raintypes admitted into the model (i.e. convective rain and residual or debris rain). The model is particularly suited for the theoretical investigation of path diversity gain since this concept owes its existence to spatial inhomogeneity of rainrate.This inhomogeneous rain attenuation model can be interfaced with an appropriate statistical rainrate prediction model, such as the Crane two‐component model, to yield more precise attenuation predictions.
Loopus opens a new dimension in satellite communications
Authors: Dondl Peter 
Published: July 2007

AbstractWithout any doubt the geostationary orbit is for many applications the most suitable orbit because of the apparent standstill of its satellites. Unfortunately geostationary satellites cannot illuminate the polar regions and furthermore the number of orbit positions is limited. With satellites on certain, dependent on the system, circular or elliptical orbits inclined against the equatorial plane, it is possible to form, off the geostationary orbit, loop‐shaped quasi‐positions—referred to as Loopus positions—which are served by satellites of alternate identity. The basic idea is to employ in shift several satellites along the same apparent track which, in the alternate play with the earth's rotation, form small loops at the celestial sphere. Change‐over takes place at the loop intersection point where a collision of the two satellites is just avoided. Thus a system with for example three satellites, which serve two Loopus positions, allows uninterrupted (quasi‐)stationary communication via earth‐stations in two coverage zones.
Intelsat tdma/dsi burst time plan development
Authors: King C. , Trusty P. , Jankowski J. , Duesing R. , Roach P. 
Published: July 2007

AbstractThe INTELSAT time‐division multiple‐access (TDMA) system, scheduled to begin operation in 1984, will be used with INTELSAT V and post‐INTELSAT V satellites. This system will operate on a 2ms time frame, employ digital speech interpolation (DSI) techniques for baseband processing, and will permit hopping between transponders. Four reference stations will provide timing and control information for each network.This paper describes the approach taken by INTELSAT in the development of burst time plans (BTPs) for the TDMA/DSI system. Network control procedures, burst scheduling and BTP information dissemination are also discussed. The software that has been developed to generate the BTPs and the associated master time plans and condensed time plans is also described.
Testing and maintenance of intelsat tdma traffic terminals—a manufacturer's perspective
Authors: Keelty J. M. 
Published: July 2007

AbstractIn this paper the related matters of testing and maintenance of TDMA traffic terminals are discussed. Generally three types of testing are required: first of all testing to ensure that the equipment complies with the stipulations of INTELSAT (called application tests herein), secondly tests to ensure that a product has been manufactured in accordance with the design (manufacturing tests) and finally maintenance tests for the purpose of resolving equipment malfunctions. It is shown that application testing can be split between tests performed on an entire terminal and tests performed on individual subsystems, and that manufacturing testing best employs automatic software‐driven facilities. Finally it is shown that the best maintenance philosophy is to adopt a circuit card replacement strategy.
The intelsat tdma burst mode link analyser
Authors: Mahoney P. 
Published: July 2007

AbstractIn any wide bandwidth transmission system, the equalization of amplitude and group delay plays an important part in obtaining acceptable transmission quality. In the forthcoming INTELSAT TDMA/DSI system the need to measure the amplitude and group delay response in a time‐shared 80 MHz transponder has led to the design and construction of a new measuring instrument: the burst mode link analyser (BMLA). In this paper, the design principles and method of operation of the BMLA are discussed, together with an overview of its internal architecture.
The TDMA tutor® computer‐based training concept
Authors: Gough R. A. 
Published: July 2007

AbstractSmall personal computers are ideally suited to the task of teaching a complex subject such as the INTELSAT TDMA/DSI system when provided with correctly designed software and supported by conventional, written material. In this paper, the design of a successful low cost computer based training system is discussed including the basic architecture, system operation, scenario technique, utilities and displays. It will be shown that the TDMA TUTOR can reproduce the most useful of the displays to be met in practice which together with an unrestricted scenario creation method produces a powerful practice‐orientated training system allowing students to experiment with ‘live’ (simulated) TDMA terminals and gain a detailed understanding of TDMA operation without risk to a real system.
Satellites versus fibre optic cables
Authors: Crispin J. , Cummins J. M. , Lemus R. , Reyna J. 
Published: July 2007

AbstractThis paper compares the capacities and costs of the new fibre optic submarine cables and the forthcoming INTELSAT VI satellites. The results indicate that, contrary to generally accepted beliefs, satellites are cheaper than fibre optic cables on a per circuit point‐to‐point basis. Moreover, satellites are shown to possess the advantage of superior overall connectivity capability, in addition to simple point‐to‐point capacity. This is expected to be very important in the choice of future cost effective facilities.
Ku‐band satellite digital transmission systems
Authors: McGann W. E. 
Published: July 2007

AbstractA nation‐wide data communications service is being placed in service by a major telecommunications carrier. This service will rely on a satellite network being provided and installed by Harris Satellite Communications Corporation.The network supports information data rates from 56 kb/s to 2·048 Mb/s. This data communications network has been architectured to include a number of innovative monitor and control functions, up‐link power control, modular equipment shelter design and a modular antenna/feed subsystem.This paper will detail this application.
Development of a prototype, experimental single‐channel sequencing navstar gps receiver: Part I—Hardware implementation
Authors: Allison M. T. , Daly P. 
Published: July 2007

AbstractLate in 1988 the Navstar GPS satellite navigation operational phase is planned to commence, offering world‐wide, continuous and precise position‐fixing and timing information to observers on land, sea, air and in space. This paper describes the development of a particular type of Navstar receiver—a single‐channel, single‐frequency, sequencing C/A code unit—and results of various tests carried out on the present phase‐II satellite constellation. Part I of the paper deals essentially with the NAVSTAR satellite system and receiver hardware implementation, whereas Part II concentrates on receiver software and system performance.
A Classification of system structures involving frequency re‐use and cross‐polar cancellation
Authors: Mc Ewan N. J. , Ghorbani A. 
Published: July 2007

AbstractThe concept of frequency re‐use based on orthogonal polarization is clarified by classifying the system structures which might be involved. Distinctions are drawn on the basis of connectivity, of whether the system is broadcast or multiplexed, and of whether the frequency re‐use is ‘full’, ‘partial’ or ‘permuted partial’. Full re‐use is defined to mean that every distinct spatial path carries two spectrally overlapping polarizations and that both of these are wanted at the receiving point. It is concluded that the partial and permuted partial forms are usually as spectrally efficient as the full, and that the partial is generally simplest.Means of cancelling cross‐polarization are also classified and related to the system structure. Discussion includes the types of cross‐coupling structure as well as the methods of deriving control signals for them.It is concluded that the classical problem of restoring mutual isolation between two incoming wanted polarizations is not the most important in practice; more common problems will arise in partial re‐use where a receiver only has to maintain its single wanted polarization orthogonal to the interfering one, or a transmitter only has to adjust a single radiated polarization. In these cases a simpler ‘unitary’ canceller can be used.
Intelnet Services—A global data distribution and collection scheme
Authors: Jamshidi Simin , Nguyen Lan N. 
Published: July 2007

AbstractResponding to the recent availability of very small earth‐stations (commonly called micro terminals) for data/voice communications, INTELSAT has introduced a new service called INTELNET.INTELNET services are designed to operate with two different modulation and coding techniques, i.e. spread spectrum and binary phase‐shift keying (BPSK) with rate 1/2 forward error correction (FEC). The INTELNET I service is a data distribution service, whereas the INTELNET II service is a data collection service. These services are facilitated by the use of micro terminals at remote locations (i.e. outposts) which will be linked through the INTELSAT space segment to relatively large INTELSAT earth‐stations (e.g. Standard A, B, C and E‐3).INTELNET services are leased transponder services offered on a range of INTELSAT satellites in C‐ or Ku‐bands on a pre‐emptible or non‐pre‐emptible basis. These services are offered on a full‐time or occasional‐use basis, by assigning predetermined satellite resources of bandwidth and power with a smallest allotment of 1 MHz.In this paper, the system design and network architecture for the INTELNET I and II services are addressed. Representative transmission parameters have also been developed for the INTELNET I and II services. System cost considerations as a result of the use of micro terminals are analysed.
Technical and economic impact of the use of standard‐B earth stations in the intelsat system
Authors: Rancy F. , Zermizoglou P. , Meunier J. 
Published: July 2007

AbstractMore than 20 years after the INTELSAT system started up, satellite technology developments have led to considerable changes in the world‐wide international satellite transmission system. This evolution and the present capabilities offered by digital technologies make it possible to reassess the potential cost advantages of standard‐B earth stations over a wider portion of international telephone transmission routes. This paper addresses the technical and economic issues raised by the characteristics of the present and planned INTELSAT satellites, together with the current capabilities of digital techniques (forward error correction, low rate encoding, time and frequency division multiple access). The foreseeable impact of the use of such techniques on overall satellite telephone transmission costs is also presented, and compared with that forecasted for fibre optic cable circuits.
Models and algorithms for optimal traffic assignment in SS/TDMA switching systems
Authors: Minoux M. , Brouder C. 
Published: July 2007

AbstractWe address here optimal design and management issues related to traffic assignment problems in SS/TDMA systems of the INTELSAT‐VI type. A general model is described in which the problem is decomposed into three sub‐problems: (1) optimal or sub‐optimal assignment of earth stations to transponders; (2) optimal decomposition of the traffic flows into blocks and sub‐blocks; and (3) optimal assignment of the traffic sub‐blocks into the TDMA frame. Methods of solution are described for solving successively each of these sub‐problems in turn. Computational experiments carried out on a series of realistic problems confirm the interest of this approach both in terms of quality of the solutions obtained and in terms of computational efficiency. Directions for future research are suggested in the conclusion.
Advanced on‐board processing for user oriented communication systems
Authors: Colombo G. , Pennoni G. 
Published: July 2007

AbstractThe continuing improvement of RF components, particularly in the field of spot‐beam antennas, combined with the steady progress in digital technology, leads us to consider the advantages of a satellite system able to provide full connectivity to ground stations operating at different data rates. For low data rates, two different access methods: continuous TDM and Multi‐carrier TDMA, are compared for earth‐stations operating at 2Mb/s. The two methods are compared from the point of view of efficiency and adaptability in a non‐uniform load environment.Some control criteria are proposed for the Multi‐carrier system.Both methods are particularly suited for small users.
System concept for a digital repeater intended for a future generation of german telecommunication satellites
Authors: Heine H. W. 
Published: July 2007

AbstractThe derivation of a system concept for the digital multi‐service repeater starts from evaluating the mission profile and the antenna concept elaborated so far. Furthermore, the repeater concept is shaped by Ka‐band propagation conditions, the kind of integration of a down‐link TV‐distribution service into the prevailing multi‐beam communications mode and readily available digital technologies. It is intended to embark on a completely regenerative approach using a unified switching concept for all services accompanied by a large amount of rearrangement functions in the foreground. An attempt is made to define those network control functions and procedures to be located on‐board exploiting the fact that the repeater already acts as a central switching node. The discussion of on‐board digital technologies concentrates upon a multicarrier demodulator concept and a candidate solution for the baseband switch. One general boundary condition is pronounced due to uncertainties about the actual traffic scenario in the future: all repeater resources must be accessible for the most important of the services considered, i.e. the provision of satellite business services.
Real‐time configurable SS/TDMA equipment for second generation french telecommunications satellite project
Authors: Oppetit A. , Thebault D. , Rousson J. L. 
Published: July 2007

AbstractThis paper describes new on‐board equipment built around a microprocessor and controlled by earth through a specialized link. It drives in real‐time a 4 × 4 microwave switch matrix (MSM) for operation in satellite‐switched time division multiple access (SS/TDMA). The system is designed to evaluate SS/TDMA performances when (i) frame and multiframe durations are changed, (ii) the switch states sequence which controls the MSM is updated in real‐time. Another specific feature of this versatile equipment is the possibility to modify upon earth request the program run by the microprocessor to be able to carry out further experiments.
On‐board processing for communication satellites: Technologies and implementations
Authors: Betaharon K. , Kinuhata K. , Nuspl P. P. , Peters R. 
Published: July 2007

AbstractThis paper presents technologies which are key candidates for advanced on‐board processing for future communication satellites. Satellite switching centres for microwave and baseband signals, on‐board coherent modems for 120Mb/s burst‐mode TDMA systems and their technologies are discussed. A brief description of on‐board demultiplexing and demodulation of low bit rate carriers is offered and study results on investigation of on‐board unique word detectors and large buffers are presented.
Advanced satellite switching centre with on‐board diagnostics
Authors: Betaharon K. , Kitazume S. , Takimoto Y. , Komiyama N. 
Published: July 2007

AbstractDesign and operation of a satellite switching centre (SSC) with its own built‐in diagnostics network are described. This SSC, designed for on‐board applications, utilizes state‐of‐the‐art technologies and techniques which have enhanced its performance significantly when compared to similar existing satellite switching centres. Additionally, unique features of this SSC are presented, specifically with respect to the built‐in diagnostic circuit which fully describes the SSCs health without disturbance of traffic signals. Finally, system aspects of utilizing such satellite switching centres are addressed.