Tesi: "Artificial satellites in telecommunication"

1

Fernández-Briseño, Raúl. "Legal aspects of telecommunication satellites operation and financing". Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19641.

Testo completo

Abstract (sommario):

Over the last years the demand for satellite communication services has been increased. Global and domestic regulatory developments and support, as well as the emerge of new services, have facilitated launcMng capabilities and reduced the costs of manufacturing, launching and operating the satellites. Financing the telecommunication satellite systems is one of the most relevant issues that prospective satellite operators face on these days. Mstitutional lenders require adequate legal advise in order to properly instrument multimillion transactions where securitization is not enough clear and risks are extremely Mgh. TMs work analyzes the most important sources of financing of telecommunication satellites and the most adequate legal structures and methods based in legislation, legal cases, jurisprudence, doctrine, and legal practice.

Gli stili APA, Harvard, Vancouver, ISO e altri

2

Hu, Yurong. "Datagram routing for low earth orbit satellite networks". Hong Kong : University of Hong Kong, 2001. http://sunzi.lib.hku.hk/hkuto/record.jsp?B23273215.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

3

Stelianos, Haralambos. "The use of commercial Low Earth Orbit satellite systems to support DoD communications". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA326969.

Testo completo

Abstract (sommario):

Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, December 1996.
"December 1996." Thesis advisor(s): Tri T. Ha and Vicente Garcia. Includes bibliographical references (p. 95-97). Also available online.

Gli stili APA, Harvard, Vancouver, ISO e altri

4

Oiesen, Eric A. "A satellite signal recognition system". Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-09052009-040513/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

5

Marston, Wendy. "Conflict of interests : the ideas, interests and institutions involved in the development of Canadian satellite policy from 1960-1980". Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60674.

Testo completo

Abstract (sommario):

This thesis looks at the development of Canadian satellite policy between 1960 and 1980 through a study of the policy decisions relating to Telesat Canada, its specific corporate structure, and mandates and ownership patterns. The analysis draws upon a modified "interplay" model, which examines public policy as an amalgam of interacting ideas, interests and institutions. On the basis of available documents, supplemented by interviews, and supporting secondary analyses, the sometimes contradictory decisions made by the DOC and the CRTC with regards to Telesat's Agreement with the Trans Canada Telephone system during this period are argued to reflect a policy process driven by the interplay of competing views of Telesat's primary purpose and, by extension, competing visions of what constitutes the public interest.

Gli stili APA, Harvard, Vancouver, ISO e altri

6

胡玉蓉 e Yurong Hu. "Datagram routing for low earth orbit satellite networks". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2001. http://hub.hku.hk/bib/B31224441.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

7

Gremont, Boris Christian. "Fade countermeasure modelling for Ka band digital satellite links". Thesis, Coventry University, 1997. http://curve.coventry.ac.uk/open/items/d85e8a85-635c-d024-3737-d1205f235596/1.

Testo completo

Abstract (sommario):

This thesis investigates the modelling of fade countermeasures (FCMs) for the design of geostationary Ka band digital satellite communication systems. The analysis focuses on a typical low-power low-rate very small aperture terminal application using adaptive forward error correction as a way of counteracting the high level of detected dynamic atmospheric fading. The management and performance of such systems is conditioned greatly by the ability of practical controllers at detecting the actual level of total signal attenuation. At 20 or 30 GHz, rain attenuation and tropospheric scintillation are the two major propagation effects of interest. Part of the solution relies on the consideration and integration of their random and dynamic nature in the design process. The finite response time of practical countermeasure systems is a source of performance degradation which can be minimised by the implementation of predictive control strategies. This is the focal point of this thesis. A novel on-line short-term predictor matched to the Ka band fading process is proposed. While the rain attenuation component is efficiently predicted, tropospheric scintillation is the source of the estimation error. To take this into account, a statistical model, based on an extension of the global fading model for rain and scintillation, is then developed so that long term performance of predictive countermeasures can be drawn. Two possible ways to compensate for scintillation-induced prediction errors, namely the fixed and variable detection margin approaches, are proposed, analysed and then compared. This is achieved by calculating the FCM utilisation factor, as well as the throughput and bit error rate performance of a typical Ka band system in the presence of dynamic fading within the context of predictive fade countermeasure control operations. In the last part of this thesis, the inclusion of instantaneous frequency scaling in the design of efficient FCM control schemes is investigated. This is applicable to systems using fade detection at a base frequency. In particular, a new statistical model, accounting for the impact of the stochastic temporal variations of rain drop size distribution on rain attenuation, is presented. This thesis further confirms that countermeasure systems are technologically viable. The consideration of more specific design problems does not change the overall validity of this statement. In this thesis, it is shown that a predictive FCM technique, based on readily available punctured convolutional codes, with their relatively modest coding gain, is sufficient to provide high link availability and user data throughput on a low-power low-rate in-bound VSAT link.

Gli stili APA, Harvard, Vancouver, ISO e altri

8

Bakari, Salim Rashid. "Solar panel development for high altitude and low earth orbit application". Thesis, Cape Peninsula University of Technology, 2010. http://hdl.handle.net/20.500.11838/2208.

Testo completo

Abstract (sommario):

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2010.
Stable and reliable source of electrical energy is a requirement for efficient operation of satellites. Several sources of electrical power for satellites exist such as fuel cells, nuclear or battery stored Direct Current energy but of late concentration has been on solar cells as the advantages compared to the other sources are many. Solar cells are p-n semiconductor devices which convert light energy into electrical energy by photovoltaic effect. The biggest drawback of solar cell energy system is the low light to electricity conversion efficiency. Apart from powering satellites, solar cells and panels have found other numerous applications such as in water pumping systems, rural electrification, street lightning. Photovoltaic principle of solar cells started way back in 1839 when Alexandre Edmund Becquerel observed that electrical currents arose from certain light induced chemical reactions. A comprehensive understanding of this phenomenon became clear when the science of quantum theory was unveiled in the early parts of the 20th century. Most solar cells and panels available today in the market are silicon based made of single junction technology. The disadvantage with single junction technology is that the p-n junction is made of a single type of solar cell material which absorbs a fraction of light wavelengths from the spectrum of light. The disability of the single p-n junction to convert all the light energy to electricity accounts for the low efficiency for the solar cells. One way to go around the problem of efficiency is to use multi-junction solar cells. Multijunction solar cells are designed to absorb a large fraction of the light spectrum and convert them to electrical energy. They are made of multiple p-n junctions made of different solar cell materials which absorb different parts of light spectrum and convert them to electrical energy. In this thesis, a design of a multi-junction solar cell for developing space solar panel is presented. The multi-junction cell has been designed from simulation results of different solar cell materials simulated with space conditions. Ideas and recommendations for future work are also presented.

Gli stili APA, Harvard, Vancouver, ISO e altri

9

Merritt, Ervin A. "Link budget design software for satellite communications". Master's thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-01262010-020138/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

10

Allnutt, Richard Mallory. "Small scale antenna diversity as a means of reducing the effects of multipath fading for handheld satellite communications systems". Diss., This resource online, 1995. http://scholar.lib.vt.edu/theses/available/etd-10202005-102841/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

11

Smith, William Whitfield Jr. "A satellite interference location system". Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/16879.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

12

Foster, Mark. "A delay-efficient satellite network for multimedia communication a pilot study /". [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1000123.

Testo completo

Abstract (sommario):

Thesis (M.S.)--University of Florida, 2002.
Title from title page of source document. Document formatted into pages; contains viii, 100 p.; also contains graphics. Includes vita. Includes bibliographical references.

Gli stili APA, Harvard, Vancouver, ISO e altri

13

Borgsmiller, Scott A. "Effects of atmospheric scintillation in K[a]-band satellite communications". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/14982.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

14

Alouini, Mohamed-Slim. "Impact of the atmosphere on K [subscript a]-Band satellite communication systems". Thesis, Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/15364.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

15

Dufour, David M. "Improved method for simulating total radiation dose effects on single and composite operational amplifiers using PSPICE". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FDufour.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

16

Gonsalvez, David J. A. "On orbital allotments for geostationary satellites /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487322984313812.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

17

Chambers, Andrew. "Viability of high availability V band satellite communication using hybrid fade mitigation". Thesis, University of South Wales, 2008. https://pure.southwales.ac.uk/en/studentthesis/viability-of-high-availability-kband-satellite-communication-using-hybrid-fade-mitigation(fba7e074-6d1b-4b4f-8c59-53b835a55e4e).html.

Testo completo

Abstract (sommario):

The C and Ku bands that have been the backbone of satellite telephony and data networks in the past are limited in the amount of bandwidth they provide. Consequently, some broadband Internet services have started to move into the Ka band in order to utilise the bandwidth at these higher frequencies. The use of higher frequencies led to fade mitigation design considerations that had not previously been necessary, as fixed power margins had been sufficient to guarantee high availability. This thesis reviews the majority of fade mitigation techniques that are available and simulates a scenario with several combined in a hybrid scheme. The simulations were made possible by several innovative components, including a near-optimum short-term fade predictor, a procedure capable of simulating the effect of site diversity with a single time series of attenuation and a dual-channel protocol structure that is able to increase availability of control information at V band. The near-optimum short-term fade predictor is compared with several other short-term fade predictors and is shown to perform better in terms of the root-mean-square error and by the cumulative distribution of over-predictions. Also noteworthy is the fact that predictors based on fade slope perform very poorly when compared with signal processing and statistical methods of prediction. The procedure capable of producing the effects of site diversity on a single time series of attenuation is described. The results of this procedure are compared with the ITU-R model for site diversity improvement and an acceptable fit is shown. A dual-channel protocol structure capable of increasing control information availability at V band is presented and the availability of this scheme is compared to the availability of current fixed-margin C and Ku band satellite links. While the availability at V band improves via this technique, it does not improve enough to compare favourably with that found in the lower frequency bands. A software turbo decoder capable of decoding the DVB-RCS turbo code is also described in this work since this was not available through other means. The fade dynamics at V band are reviewed and compared with the ITU-R models. The fade slope model gives a good visual fit but the fade duration model is very inaccurate. Finally, the simulation results show that high availability satellite communication is possible at V band, critically, if both site diversity and frequency diversity are available to mitigate the hub and VSAT fading respectively. Signal processing and power control are also found to be complementary techniques.

Gli stili APA, Harvard, Vancouver, ISO e altri

18

Wang, Cou-way. "Optimization of orbital assignment and specification of service areas in satellite communications /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu148726636233915.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

19

Score, Robert H. "An examination of XM satellite subscriber's perceptions of satellite radio compared to traditional AM/FM radio". Instructions for remote access. Click here to access this electronic resource. Access available to Kutztown University faculty, staff, and students only, 2002. http://www.kutztown.edu/library/services/remote_access.asp.

Testo completo

Abstract (sommario):

Thesis (M.S.)--Kutztown University of Pennsylvania, 2002.
Source: Masters Abstracts International, Volume: 45-06, page: 2720. Typescript. Abstract precedes thesis as preliminary leaves 1-2. Includes bibliographical references (leaves 34-35).

Gli stili APA, Harvard, Vancouver, ISO e altri

20

Thompson, Richard. "Evaluating TCP/IP performance over satellite networks". Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49954.

Testo completo

Abstract (sommario):

Thesis (MScEng) -- Stellenbosch University, 2004.
ENGLISH ABSTRACT: Interest in TCP/IP as a communication protocol for use in space communication has increased substantially with the growth of the world wide web (WWW). TCP/IP is a relevant communication protocol for space based communication systems that need to access the broader terrestrial communication network. Low Earth Orbit(LEO) satellites have very short delay times between themselves and the ground, and correspondingly very short connection times. Staying in contact with a LEO satellite continuously through a space-based network requires large constellations of satellites and complex routing strategies. Connectivity with the world wide web using a widely accepted protocol such as TCP/IP is desirable because it would make communication with the satellite over a terrestrial station possible, were it to route communication onto the WWW. This thesis looks at the expected TCP/IP performance over satellite network links, identifies problem areas for current TCP/IP technologies, and makes suggestions for optimizing TCP/IP over such links. The thesis also introduces a new performance benchmark, the equivalence level, allowing for the simplified description of TCP throughput behaviour over a broad range of network parameters. The performance of the Linux kernel release 2.4.18 TCP/IP stack is also evaluated.
AFRIKAANSE OPSOMMING: Die belangstelling in TCP/IP as ’n kommunikasie protokol vir gebruik in die ruimte het kenmerklik toegeneem met die groei van die wereld wye web (WWW). TCP/IP is ’n relevante protokol vir kommunikasie stelsels in die ruimte, veral met die doel om toegang tot land gebaseerde kommunikasie netwerke te kry. Lae wentelbaan sateliete het baie kort vertragingstye tussen die aarde en die sateliet, en gevolglik baie kort verbindingstye. Groot sateliet konstelasies en komplekse verbintenis strategie word benodig om ’n lae wentelbaan sateliet deurentyd in kontak te hou met ’n ruimtegebaseerde netwerk. Verbinding met die wereld wye web deur die gebruik van ’n wyd aanvaarde protokol, soos TCP/IP, is wenslik, want dit sal kommunikasie met die sateliet oor ’n aardgebaseerde stasie moontlik maak, sou dit kommunikasie oor die wereld wye web stuur. Hierdie tesis kyk na die verwagte werking van TCP/IP oor sateliet netwerk konneksies, identifiseer probleme met huidiglike TCP/IP tegnologie, en maak voorstellings vir die optimale funtionering van TCP/IP oor sulke konneksies. Hierdie tesis stel ook ’n nuwe werkverrigtings maatstaf, die gelykheidsvlak, wat die vereenvoudige beskrywing van TCP/IP data tempo gedrag oor ’n groot variasie van netwerk parameters toelaat. Die werking van die Linux Kernel 2.4.18 TCP/IP stapel word ook geevalueer.

Gli stili APA, Harvard, Vancouver, ISO e altri

21

Fremeth, Howard. "The creation of Telesat: Canadian communication policy, Bell Canada, and the role of myth (1960-1974) /". Burnaby B.C. : Simon Fraser University, 2005. http://ir.lib.sfu.ca/handle/1892/2098.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

22

Polaha, James Henry. "An analysis of low-earth-orbit-satellite communication systems". Thesis, Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/74533.

Testo completo

Abstract (sommario):

There is an ever increasing need for low-cost communication systems in the world. One such system, low-earth-orbit satellites, can provide store-and-forward, as opposed to real time, communication for many earth stations. The advantages and disadvantages of such a system is presented. Material covering protocols and communications architectures is elaborated upon for the use of amateur radio communications. Doppler shift and its effect on satellites in low-earth-orbit is examined. Efficiency and throughput of the Amateur X.25 Protocol will be explored. The last chapter entails the analysis of the PACSAT experiment.
Master of Science

Gli stili APA, Harvard, Vancouver, ISO e altri

23

Haidara, Fatim M. "Characterization of tropospheric scintillations on Earth-space paths in the Ku and Ka frequency bands using the results from the Virginia Tech OLYMPUS experiment". Diss., This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06062008-170624/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

24

Harrell, Andre T. "Wireless technology via satellite communications for peacekeeping operations". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2001. http://library.nps.navy.mil/uhtbin/hyperion-image/01Sep%5FHarrell.pdf.

Testo completo

Abstract (sommario):

Thesis (M.S. in Information Systems Technology)--Naval Postgraduate School, September 2001.
Thesis advisor(s): Tri T. Ha, Nancy Roberts. Includes bibliographical references (p. 85-87). Also available online.

Gli stili APA, Harvard, Vancouver, ISO e altri

25

Ah-Thew, George Patrick. "Doppler compensation for LEO satellite communication systems". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0005/NQ42831.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

26

Kassianides, Constantinos N. "A study of the effects of scintillation on digital satellite communication systems". Thesis, University of South Wales, 2002. https://pure.southwales.ac.uk/en/studentthesis/a-study-of-the-effects-of-scintillation-on-digital-satellite-communication-systems(19190903-59f8-4350-9a59-2d2a70e1a623).html.

Testo completo

Abstract (sommario):

The growth of satellite communication industry and the need to offer new and better services, to compete with optical fiber systems, have driven the satellite industry to search for higher bandwidth and improved cost of services. Higher frequency bands, such as Ka and V-band, came into play. These frequency bands have the advantage of efficient use of spectrum, the ability to transfer data at much higher rates, and the use of smaller antennas resulting in lower cost for the user. A major drawback though, is the severity of propagation impairments. Scintillation becomes important for low-fade margin systems operating at high frequencies and with low elevation angles and therefore must be taken into account in the design of satellite communication systems. The first part of the thesis deals with the analysis of beacon data and presentation of various statistics, namely short and long-term distributions of scintillation amplitudes and intensity. Their correlations with meteorological parameters are also presented. A dynamic model of tropospheric scintillation is developed, which permits the generation of scintillation time series based on known scintillation characteristics, such as spectral shape and probability density function. The model employs readily obtainable input parameters (antenna diameter, path elevation angle, frequency, ground temperature and humidity) and yields statistics that compare extremely well with existing prediction models as well as measured scintillation data (up to the fourth moment). Important applications of the new model are for simulating the performance of scintillation-degraded communication links and predicting required scintillation fade margins. The second part of the thesis investigates the effects of scintillation on digital satellite communication systems using simulations implemented in COSSAP. Simulation results show that the higher the order of the modulation that is being used, the larger is the effect of scintillation on the bit error rate performance of the link. In the third part of the thesis, fade mitigation techniques to overcome the effects of scintillation fading are discussed. Analysis of an adaptive modulation system using three modulation techniques is presented and its advantages demonstrated. The adaptive system can be used to mitigate scintillation fading and at the same time increase the capacity of the system, decreasing system outage time through an efficient utilisation of available resources. In the last part, data transfer scenarios in VSAT systems incorporating adaptive modulation, ARQ and adaptive up-link power control are presented. The implementation of the adaptive system in a COSSAP simulation platform is discussed and individual adaptive components are simulated and presented in detail.

Gli stili APA, Harvard, Vancouver, ISO e altri

27

Choy, Faith. "Performance investigation of multi-element antenna terminals for personal communications : TDMA LEOS system applications /". [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16140.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

28

Müller, Joachim W. "International collaboration in advanced technology : the case of the European communication satellite programme". Thesis, University of Oxford, 1988. http://ora.ox.ac.uk/objects/uuid:9b633345-23dd-483c-9623-5ed5e6c16321.

Testo completo

Abstract (sommario):

Governments have funded the development and production of advanced technology in order to establish supply security and/or to achieve economic growth. The policy of government funding includes three alternatives: the two basic options of maintaining a national project or participating in international collaboration involving a number of sovereign states, and the third option of doing both in parallel. The study examines international collaboration in such a way as to assist in the selection of the appropriate policy option. Particular attention is paid to the perspective of small and large, advanced and less advanced European countries. The research problem is addressed by focusing exclusively on those results which distinguish international collaboration from a national project, summarised under the concepts of collaborative sharing and collaborative efficiency. The former identifies the sharing of funding and technology not to be found in a national project. The latter identifies the difference in efficiency between international collaboration and a national project. Efficiency, indicated by cost, quality and time, is examined under the headings of policy-making, executive management, industrial rationalisation and production volume. Furthermore, collaborative sharing and efficiency are examined in the context of parallel national projects. This focus on the differences between the policy options provides the basis for selecting the appropriate one. Previous studies fail to give convincing answers to the research problem: they concentrate on collaborative efficiency while neglecting collaborative sharing, and they disagree over whether international collaboration or a national project is more efficient. This study attempts to overcome these shortcomings by examining a major case study of international collaboration, namely the European Communication Satellite Programme. The following conclusions are established. To achieve supply security, the collaborative option is considered appropriate for the large, advanced European country, and the parallel option for the large, less advanced countries. To achieve economic growth, the national option is appropriate for the advanced European countries. The smaller, less advanced countries are seen to play only a limited role in government funding of advanced technology.

Gli stili APA, Harvard, Vancouver, ISO e altri

29

Henkle, Thomas Grove III. "Performance characteristics of a multiple use Ku-band satellite network". Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/44646.

Testo completo

Abstract (sommario):

Construction of a Ku-band earth station was completed in August 1989 at the teleport in the Corporate Research Center of Virginia Polytechnic Institute and State University. At that time specific applications for the terminal were being determined. Several satellite networks which can use the Ku-band earth station are explored in this thesis. System level designs are presented for each network. The anticipated performance of the network during clear sky conditions and during periods of rain fade conditions are calculated. To aid in these calculations the software package LAMP was developed.

detailed system design of a VSAT network is given in later chapters. The development of VSAT networks considers multiple access and data traffic control protocols. VSAT network performance under various traffic conditions also is determined.
Master of Science

Gli stili APA, Harvard, Vancouver, ISO e altri

30

Kaul, Ranjana 1951. "Regulation of satellite telecommunications in India". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=83954.

Testo completo

Abstract (sommario):

Commercialization of space activities particularly harnessing satellites for telecommunication in the 1970's is perhaps the most dynamic development of the twentieth century comparable only to the industrial revolution of the seventeenth century. The possibilities of civilian applications of satellite technology confined to its military use until the recent past has raised urgent questions of policy and regulations both nationally and internationally.
The main objective of the thesis is to review the development of satellite telecommunication with particular reference to India. The thesis assesses the present access status and the regulatory regime, analyzes general challenges of deregulation including concerns of national security, fair competition, equal opportunity for service providers and manufacturers and above all consumer protection. It examines the how the Canadian CRTC and American FCC are addressing the current challenge posed by rapid technological developments and consequent convergence of telecommunications and broadcasting as well as lessons India could learn from the Canadian and American experiences. Finally suggestions are made for a possible logical direction for India's future telecom policy, in particular and the commercialization of space activities, in general.

Gli stili APA, Harvard, Vancouver, ISO e altri

31

Narasimhan, Priya. "An evaluation of realistic TCP traffic in satellite networks". Ohio : Ohio University, 2002. http://www.ohiolink.edu/etd/view.cgi?ohiou1020344432.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

32

Knoll, James A. "Convergence of the Naval information infrastructure /". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FKnoll.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

33

Knupp, Greg L. "System engineering of a crosslink for geostationary communications satellites". Master's thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-03172010-020055/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

34

Evers, Brent A. "ACTS radiometers and a comparison of atmospheric attenuation derived form temperature-humidity and radiometric data". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-12042009-020308/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

35

Smith, David. "Satellite data transmission by means of a multi-channel system". Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/1213.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

36

Lo, Jonathan Lok-Chuen. "Selected problems analysis for Little LEO data communication service development /". [St. Lucia, Qld.], 2000. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16165.pdf.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

37

Sarrocco, Claudia. "Legal aspects of the mobile satellite telecommunications services". Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31173.

Testo completo

Abstract (sommario):

Thanks to the use of satellite technology, mobile personal telecommunications systems are able to provide communications simultaneously anywhere on the Earth's surface. The implementation of such systems raises several regulatory issues: after a brief explanation of the technical characteristics of different satellite systems in the first chapter, the second chapter will introduce the principles of space law relevant to satellite communications, with particular attention to the provisions which the development of global satellite telecommunication system could infringe. In the third chapter, there will be place for further analysis of international regulations established in the framework of the International Telecommunication Union and the World Trade Organisation, dealing more specifically with satellite telecommunications. The discipline established by the former organisation aims to the optimal management of the orbit and spectrum resources, particularly controversial because of the divergence of interests and exigencies of the member countries, whereas the latter intervened in the liberalisation of the telecommunication services, with the purpose to create an open environment for their diffusion. Furthermore, telecommunication activities are subjected to national regulation. The domestic discipline pertaining to global mobile satellite telecommunication services will be analysed in the fourth chapter, with particular attention to the U.S. Federal Communication Commission regulations and to the developments of Italian legislation in the light of the recent European initiatives in the field. National authorisation requirement conditions, in spite of the international effort toward regulatory harmonisation and liberalisation, are the key elements in the deployment of global mobile telecommunications services. National authorities should not continue to function solely on the basis of their national considerations, but be more flexible and open to cooperation, a

Gli stili APA, Harvard, Vancouver, ISO e altri

38

Pollard, Kimberley Jeanne. "Study of slant path attenuation ratios derived from a dual-polarized radar". Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03122009-040448/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

39

Bochinger, Steve. "The implications of the privatization of space telecommunications on international organizations /". Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31150.

Testo completo

Abstract (sommario):

If the privatization of space telecommunications, because of its impacts, has been subject to various studies, this thesis focuses the analysis of this phenomenon on a particular point: its implications on international organizations.
Because of the evolution of the sector, international satellite organizations have undertaken for around ten years several internal reforms that lead today to the privatization of the three major organizations: Intelsat, Inmarsat and Eutelsat. These transformations constitute a particular sensitive issue as these organizations have been initially established so that to exploit satellite systems for the general interest of their members.
The impact of this phenomenon is no less considerable on the ITU, in charge of the international regulation, from a regulatory but also structural point of view. Moreover, the liberalization of telecommunication market undertaken under the aegis of the WTO grants to this organization a new major place in space telecommunication regulation.

Gli stili APA, Harvard, Vancouver, ISO e altri

40

Allnutt, Richard Mallory. "Total power radiometers at 12, 20 and 30 GHz used in the OLYMPUS experiment at Virginia Tech". Thesis, This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-08142009-040215/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

41

Cawood, Andrew Dudley. "Adaptation, optimisation and simulation of the CSMA/CA protocol for a low earth orbit satellite UHF link". Thesis, Link to the online version, 2006. http://hdl.handle.net/10019/1608.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

42

Christelis, Christian. "Volumetric data throughput optimisation by dynamic FEC bearing frame length adaptation". Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4337.

Testo completo

Abstract (sommario):

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The telecommunications link between a LEO satellite and a rural ground station with a non-tracking antenna, has a strongly varying link quality and a short communications window. The satellite acts as a store-and-forward node between ground stations. The TC-SDLP and an FTP protocol form a shallow protocol stack, which excludes unneeded protocol functionality and the resulting overhead. Coding gain, introduced by BCH FEC in the TCSDLP, allows for link quality improvement. The core of this thesis is an improvement of the TC-SDLP to maximise effective payload data throughput, or goodput. This improvement was achieved by creating an optimal segment length selection metric based on the BER. Since the BER is not determinable from within the TC-SDLP, the metric was twice determined; once based on the FER and finally based on time delays. The work includes an extensive background study, which consists of space standardisation, orbital physics, error detection and correction, space datalink protocols, data throughput and culminating in the protocol stack design. The project specific link budget calculation is presented. The optimal segment length policy was mathematically determined. Asimulation model of the TC-SDLP was used as a proof of concept for the effective throughput and give a performance benchmark. Finally a TC-SDLP implementation offers a real world performance demonstration.
AFRIKAANSE OPSOMMING: Die telekommunikasie skakel tussen ’n lae aardomwenteling (LEO) sateliet en ’n plattelandse grondstasie met ’n nie-volg antenna, het ’n skakelkwaliteit wat in ’n groot mate varieer en ’n kort kommunikasievenster. Die sateliet tree op as ’n stoor- en- aanstuur node tussen grondstasies. Die TC-SDLP en ’n leêr oordrag protokol (FTP) vorm ’n vlak protokol stapel, wat onnodige protokol funksionaliteit en die gevolglike opkoste uitsluit. Kode aanwins, wat deur die BCH FEC in die TC-SDLP, aangebring word, verbeter die skakelkwaliteit. Die kern van hierdie tesis is ’n verbetering van die TC-SDLP om sodoende die ware deurvoer van nuttige vragdata te maksimimeer. Hierdie verbetering is bereik deur die skep van ’n optimale segmentlengte-seleksie metode gebaseer of die bit fout tempo (BER). Aangesien die BER nie bepaal kan word vanuit die TC-SDLP nie, is die maatstaf twee keer bepaal; die eerste keer is die bepaling gebaseer op die raamwerk fout tempo (FER) en die finale bepaling op tyd vertragings. Die tesis sluit ’n omvattende agtergrondstudie in, wat bestaan uit ruimte standardisering, wentelbaan fisika, die opspoor en regstel van foute, ruimte inligtingskakel protokol en deurstuur van data wat uitloop op die protokol ontwerp. Daar word aangedui hoe die berekening van die begroting vir die skakel van toepassing op die spesifieke projek, gedoen is. ’n Wiskundige analise van die optimale segmentlengte s ook gedoen. ’n Simulasie model van die TC-SDLP is gebruik as ’n bewys van die konsep vir die ware deurset en gee ’n prestasie maatstaf. Laastens bied die TCSDLP implementering ’n ware wereld prestasie demonstrasie.

Gli stili APA, Harvard, Vancouver, ISO e altri

43

Schmier, Robert Gordon. "Fade durations in satellite-path mobile radio propagation". Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91053.

Testo completo

Abstract (sommario):

Fades on satellite to land mobile radio links are caused by several factors, the most important of which are multipath propagation and vegetative shadowing. Designers of vehicular satellite communications systems require information about the statistics of fade durations in order to overcome or compensate for the fades. Except for a few limiting cases, only the mean fade duration can be determined analytically, and all other statistics must be obtained experimentally or via simulation. This report describes and presents results from a computer program developed at Virginia Tech to simulate satellite path propagation of a mobile station in a rural area. The simulator was developed using 869 MHz balloon data provided by Wolfhard Vogel of the University of Texas at Austin and was tested using helicopter data provided by Wolfhard Vogel and Julius Goldhirsh of the Johns Hopkins University Applied Physics Laboratory. It generates rapidly-fading and slowly-fading signals by separate processes that yield correct cumulative signal distributions and then combines these to simulate the overall signal. This is then analyzed to yield the statistics of fade durations.
M.S.

Gli stili APA, Harvard, Vancouver, ISO e altri

44

Neumeister, Kenneth Eugene. "Design and analysis of ground stations for Pacsat applications". Thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-03122009-040419/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

45

Hayes, David Paul. "Performance analysis of VSAT networks". Thesis, Virginia Tech, 1987. http://hdl.handle.net/10919/44052.

Testo completo

Abstract (sommario):

Very small aperture terminal (VSAT) networks offer a solution to the increasing demand for low-density voice and data communications. Spread Spectrum and single-channel-per-carrier (SCPC) transmission techniques work well for multiple access purposes while allowing the earth station antennas to remain small. Direct sequence code division multiple access (DS-CDMA) is the simplest spread spectrum technique to use in a VSAT network, since a frequency synthesizer is not required for each terminal. This thesis examines DS-CDMA and SCPC Ku-band VSAT satellite systems for low-density (64 kbps or less) communications. It develops methods for calculating PN coding cross-correlation interference losses and satellite transponder effects, and it includes these losses in a performance analysis of 50 channel full mesh and star network architectures. It demonstrates selection of operating conditions producing optimum performance.
Master of Science

Gli stili APA, Harvard, Vancouver, ISO e altri

46

Badri, Moncef. "Performance analysis of star architecture packet-switched VSAT networks using random code division multiple access". Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/91081.

Testo completo

Abstract (sommario):

The intent of this research is to provide a performance analysis of multiple access protocols in packet-switched Very Small Aperture Terminal (VSAT) satellite communication networks. This research consisted of three major thrusts. First, we analyzed the average time delay of the broadcast Time Division Multiplexing (TDM) outbound channel (hub to VSAT). Second, a throughput performance analysis of an asynchronous Direct-Sequence Code Division Multiple Access (DS-CDMA) communication system is carried out for the inbound line (VSAT to hub). Each channel was characterized by its bit error probability, and transmits fixed-length packets generated according to a Poisson process in an unslotted environment. Third, we presented a delay analysis of the ALOHA DS-CDMA/TDM channel to determine the total service time of a packet originating from either the VSAT or the hub station. In addition to its multiple access capability, this thesis is concerned with the use of direct-sequence spread-spectrum signaling primarily because of its ability to combat interference. Emphasis is placed on average throughput performance, and on the average packet delay after solving for the steady state probability generating function of the station queue size. Then, a discussion of the effect of finite buffer size, and an analysis relating the probability of buffer overflow to packet statistics and buffer size is presented. Because of the bursty nature of a traffic originating from the VSAT’s, the Automatic Repeat Request (ARQ) technique used for error control is the Stop-and-Wait (SW) protocol. It is used as a retransmission strategy in both the Asynchronous Time Division Multiplexing (ASTDM) and the ALOHA DS-CDMA channels.
M.S.

Gli stili APA, Harvard, Vancouver, ISO e altri

47

Hossain, Ziaul. "A study of mechanisms to support variable-rate Internet applications over a multi-service satellite platform". Thesis, University of Aberdeen, 2015. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=225781.

Testo completo

Abstract (sommario):

Satellite broadband has the potential to provide Internet connectivity to people and places that are unreachable using other wired/wireless technologies. It is therefore a critical component of any service seeking to provide universal coverage. A universal service needs to support a range of Internet applications. While there is existing work on bulk and interactive applications with a characteristic transmission rate, popular Internet applications such as web browsing, web video download or variable-rate voice result in a network traffic that varies its transmission rate. This thesis first investigates the interaction of satellite resource request mechanisms with the quality of service offered to these variable-rate applications using a satellite platform based on DVB-RCS2. It shows that a flexible QoS architecture can be achieved by a combination of resource request methods and network-layer queuing. Variable-rate traffic also poses challenges to the widely deployed Transport Control Protocol (TCP). Previous work analysed the interaction with the congestion control algorithms and proposed Congestion Window Validation (CWV) to constrain the congestion window to the amount of traffic a transport has sent. TCP JAGO studied this problem for variable-rate bursty applications and proposed new algorithms; but these were shown to have drawbacks and there were no guidance on how to implement. This thesis therefore presents, newCWV, a practical mechanism to provide an appropriate estimate of the available path capacity and corresponding congestion control behaviour. This benefits variable-rate applications with shorter transfer durations, but has a consequence of allowing larger traffic bursts into the network that can increase packet loss. Burst mitigation techniques, such as TCP pacing, are proposed to deal with this. These techniques are implemented and tested in the Linux TCP/IP stack, where newCWV improves the burst transfer time. This benefit is particularly significant for the large delay of broadband satellite systems.

Gli stili APA, Harvard, Vancouver, ISO e altri

48

Raines, Richard A. "Performance modeling and analysis of parallel processing and low earth orbit satellite communications systems /". This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06062008-164502/.

Testo completo

Gli stili APA, Harvard, Vancouver, ISO e altri

49

Beaudry, Catherine. "Enterprise in orbit : the supply and demand for communication satellites, 1964-1992". Thesis, University of Oxford, 1998. http://ora.ox.ac.uk/objects/uuid:df766834-81c3-4e5b-9158-9240b441bcf8.

Testo completo

Abstract (sommario):

The objective of this study is to develop a general understanding of the evolution of the commercial communication satellite industry. Initial information classifies the industry as an oligopoly with the vendors as price setters. The approach to this thesis is to examine the supply and demand of satellites as a capital good. Assuming the demand curve slopes downwards, the study examines the change in the price of a standard unit satellite. The underlying motivation is the conventional identification problem. Over three generations, the technical attributes of communication satellites are advancing. Taking the hedonic regression approach, the price of satellites is shown to decrease over time. Exploring the relationship between price and complexity, it is demonstrated that in the short-run the oligopoly structure of this industry is accompanied by a simple form of cost-plus price-setting. This finding solves the identification problem, so that simultaneous equation methods are not required. Assuming a constant degree of monopoly power in the industry, changes in multi-factor productivity are estimated. Productivity growth increases until 1980, but decreases slightly afterwards. The learning coefficients estimated for this industry are smaller than those found for the airframe industry. The fall in quality-corrected prices, however, is not big enough to support the interpretation that the expansion of satellite capacity was due to supply shifts along a stationary market demand schedule. Factors driving demand lead to a faster rate of expansion outside the original western world, but in the second half of the period, the ability to use software data compression moderated the rate of growth of demand for new satellites. The study explains the adjustment of the stock of satellite capacity in response to the desired stock: the speed at which countries adjust their stock depends on their characteristics and regional profile.

Gli stili APA, Harvard, Vancouver, ISO e altri

50

Smith, William Travis. "Statistical modeling for land mobile satellite communications". Thesis, Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/91072.

Testo completo

Abstract (sommario):

The Land Mobile Satellite System (LMSS) to be available in the 1990 time frame will provide connection between mobile vehicles and the conventional terrestrial communication network. The design is dependent on the propagation characteristics of the land mobile satellite signal. Unlike fixed satellite links, there is blockage in the line of sight path, mainly in the form of vegetative shadowing. The focus of this study is to develop models for the fading of the received satellite signal. A brief review of the physics and statistics associated with mobile propagation is presented. This is followed by a review of current literature and experiments. The modeling of the cumulative distribution function for a totally vegetatively shadowed mobile (VS distribution) is presented. The VS distribution is then used in a model for the cumulative distribution function of a partially shadowed mobile. The complete model for partially shadowed routes permits calculations for arbitrary combinations of open and forested terrain. Comparisons are made to data reported for partially shadowed routes. The deterministic path model (DPM) developed in an earlier effort is a geometrically based tool for determining the signal path length through a stand of trees. It is expanded to give approximate expressions for the statistical parameters describing the fading of the line-of-sight component of the received signal. New expressions for the secondary statistics of a totally vegetatively shadowed mobile are derived. These new expressions are then used in models for the level crossing rate and average fade duration of a partially shadowed mobile. Comparisons are made to data reported for partially shadowed routes.
M.S.

Gli stili APA, Harvard, Vancouver, ISO e altri

Tesi sul tema "Artificial satellites in telecommunication"

Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili