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Switch diversity system in mobile radio.Vu, Van Van. January 1978 (has links) (PDF)
Thesis (M.Eng.Sc. 1979) from the Department of Electrical Engineering, University of Adelaide.
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Theory of Stochastic Local Area Channel Modeling for Wireless CommunicationsDurgin, Gregory David 11 December 2000 (has links)
This dissertation outlines work accomplished in the pursuit of this degree. This report is also designed to be a general introduction to the concepts and techniques of small-scale radio channel modeling. At the present time, there does not exist a comprehensive introduction and overview of basic concepts in this field. Furthermore, as the wireless industry continues to mature and develop technology, the need is now greater than ever for more sophisticated channel modeling research.
Each chapter of this preliminary report is, in itself, a stand-alone topic in channel modeling theory. Culled from original reports and journal papers, each chapter makes a unique contribution to the field of channel modeling. Original contributions in this report include:
1. joint characterization of time-varying, space-varying, and frequency-varying channels under the rubric of duality
2. rules and definitions for constructing channel models that solve Maxwell's equations
3. overview of probability density functions that describe random small-scale fading
4. techniques for modeling a small-scale radio channel using an angle spectrum
5. overview of techniques for describing fading statistics in wireless channels
6. results from a wideband spatio-temporal measurement campaign
Together, the chapters provide a cohesive overview of basic principles. The discussion of the wideband spatio-temporal measurement campaign at 1920 MHz makes an excellent case study in applied channel modeling and ties together much of the theory developed in this dissertation. / Ph. D.
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Frequency discriminator detection in frequency-selective fading environments.Rohani-Mehdiabadi, Bijan January 1998 (has links)
In recent years, millions of customers all over the world have been subscribing to mobile telephony services which are based on modern digital transmission. At the high transmission bit rates that these systems use, the mobile radio channel exhibits frequency-selective fading characteristics. Under such conditions, the received signal could experience significant intersymbol interference (ISI) from severe distortion to the waveform of the received baseband signal. Therefore, such techniques as adaptive waveform equalisation or adaptive maximum likelihood sequence estimation (MLSE) are used in modern digital mobile radio telephone systems to combat this undesirable ISI. These adaptive schemes have almost always been used in conjunction with coherent demodulation in the receivers.This study examines the application of noncoherent demodulation, in the form of frequency discriminator detection, as an alternative to coherent demodulation. The GSM (Global System for Mobile Communications) standard has been used as the basis for this investigation. It has been shown analytically that in the presence of frequency-selective fading, a propagation environment common to the GSM system, the use of frequency discriminator detection gives rise to nonlinear ISI in the demodulated signal. It has also been shown that frequency-selective fading could cause large unwanted "spikes" to appear in the demodulated signal, thus leading to a severe degradation in the bit-error-rate (BER) performance. Consequently, several waveform distortion cancellation schemes for combatting the nonlinear ISI have been formulated. The BER performances of these proposed schemes, under various propagation conditions, have been studied by computer simulation.Furthermore, it has been observed that the undesirable "spikes", that occur in the demodulated signal due to frequency-selective fading, could be ++ / suppressed by the use of inverse-limiting in conjunction with frequency discriminator detection. As a result, an effective adaptive detection scheme has been formulated, based on modelling the combination of the GMSK modulator, the mobile channel, the frequency discriminator, and any transmit and receive fitters, as a finite-state machine. The transmitted data is then detected using an MLSE. The BER performance of this proposed adaptive detection scheme has been extensively investigated by computer simulation. This has been carried out assuming various propagation conditions, including the two-ray fading channel model with equal path powers and relative delays of up to four bit periods, the maximum relative delay considered in the GSM system. Also, the effectiveness of the proposed adaptive detection scheme in combatting IS] has been investigated by computer simulation based on the six-ray GSM empirical propagation models for typical urban (TU), hilly terrain (HT) and rural area (RA) environments. The computer simulated results confirm that the voice grade performance required for the GSM system could be achieved by the proposed adaptive detection scheme in all the recommended GSM propagation models considered. Furthermore, the BER performance of the receiver remains unaffected by a carrier frequency offset of up to 2 kHz.
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Band sharing between CDMA based non-geostationary satellite personal communication networks (S-PCN)Aziz, Hafeez Mohammad January 2000 (has links)
During the past few years, a worldwide interest and unanimous consensus has arisen on personal communication services (PCS), where satellites can play a crucial role in a global scenario for the provision of PCS's all over the world. While for maritime and aeronautical communication services, the mature technologies of geostationary earth orbit (GEO) satellite systems seem the most suitable for present and future enhanced systems, other orbital configuration such as low earth orbit (LEO) and medium earth orbit (MEO) are being considered for the provision of satellite personal communication services to hand-held mobile terminals. One of the main objectives of personal communication services is the capability to provide personal (or continuous) mobility, communication anytime, anywhere. In general, satellite systems can provide a limited capacity with respect to terrestrial networks, nevertheless they are particularly suited in order to cover large terrestrial areas offering a scarce amount of traffic. The problem of radio frequency management for mobile applications has been addressed by World Administrative Radio Conference (WARC-92). One of the most relevant decisions taken at WARC-92 was to allocate the radio determination satellite system (RDSS) 1610-1626.5 MHz (L-Band) and 2483.5-2500 MHz (S-Band) slots to LEO satellite services on a worldwide, primary basis. This enables "big LEO's" to have a reasonable amount of spectram (i.e. capacity) to serve a substantial number of subscribers. However, the available amount of spectrum at L-band and S-band out of WARC-92 appears hardly sufficient to permit several systems to operate. Hence, to enable all the systems to operate and fulfil the capacity demand, S-PCNs need to share the limited available frequency spectrum. In this thesis we have proposed and evaluated a new fully overlapped band sharing scheme for mobile satellite systems operating in a land mobile satellite channel environment. The results show that the mobile satellite systems can share the limited available bandwidth. However, the overall system capacity of the MSS has been reduced due to excess intersystem interference. In order to reduce the excess inter-system interference a new enhanced overlapped band sharing protocol is proposed. The performance of this optimised band sharing scheme outperforms the conventional band segmentation scheme. Thus, achieving superior overall system capacity.
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On air.January 1997 (has links)
Lo Kong Alvin. / "Architecture Department, Chinese University of Hong Kong, Master of Architecture Programme 1996-97, design report." / Includes bibliographical references. / Chapter 1.0 --- INTRODUCTION / Chapter 1.1 --- GENERAL BACKGROUND / Chapter 1.2 --- DEFICIENCY IN RTHK / Chapter 1.3 --- TECHNOLOGICAL REVOLUTION / Chapter 1.4 --- COMPARISON / Chapter 1.5 --- RATIONALIZATION / Chapter 1.6 --- ARCHITECTURAL RESPONSE / Chapter 1.7 --- SUMMARY / Chapter 1.8 --- METHODOLOGY / Chapter 2.0 --- BACKGROUND OF RTHK / Chapter 2.1 --- OBJECTIVES / Chapter 2.2 --- ROLES OF RTHK / Chapter 2.3 --- HISTORY / Chapter 2.4 --- ORGANIZATION / Chapter 2.5 --- OPERATION / Chapter 2.6 --- PROGRAM / Chapter 3.0 --- PHYSICAL CONDITIONS OF EXISTING RTHK / Chapter 3.1 --- REGIONAL CONTEXT OF KOWLOON TONG / Chapter 3.2 --- SITE AND FACILITIES / Chapter 3.3 --- BROADCASTING HOUSE / Chapter 3.4 --- TELEVISION HOUSE / Chapter 3.5 --- EDUCATION TELEVISION CENTER / Chapter 4.0 --- THE PROPOSAL / Chapter 4.1 --- MISSION / Chapter 4.2 --- GOALS / Chapter 4.3 --- OBJECTIVES / Chapter 4.4 --- PERFORMANCE REQUIREMENTS / Chapter 4.5 --- SITE OPPORTUNITIES / Chapter 4.6 --- SCHEDULE OF ACCOMMODATION / Chapter 5.0 --- DESIGN REPORT / Chapter 5.1 --- CONCEPTS / Chapter 5.2 --- DESIGN DEVELOPMENT / Chapter 5.3 --- DESIGN OPTIONS / Chapter 6.0 --- SCHEMATIC DESIGN / Chapter 6.1 --- CONCEPT / Chapter 6.2 --- DESIGN OPTIONS / Chapter 6.3 --- DETAIL DESIGN / Chapter 7.0 --- RESEARCH AND FIELD WORKS (I) ENERGY / Chapter 7.1 --- PHOTOVOLTAIC ENGINEERING / Chapter 7.2 --- STRUCTURE OF A PHOTOVOLTAIC SYSTEM / Chapter 7.3 --- ENERGY STORAGE / Chapter 7.4 --- APPLICATION: SOLAR TELECOMMUNICATION / Chapter 8.0 --- RESEARCH AND FIELD WORKS (II) STUDIO / Chapter 8.1 --- TYPES OF STUDIOS / Chapter 8.2 --- PERFORMANCE STUDIOS / Chapter 8.3 --- PRODUCTION STUDIOS / Chapter 8.4 --- POSTPRODUCTION STUDIOS / Chapter 8.5 --- MOBILE STUDIOS / Chapter 8.6 --- PORTABLE EQUIPMENT / Chapter 8.7 --- STUDIO DESIGN / Chapter 8.8 --- ERGONOMICS / Chapter 9.0 --- CASE STUDIES / Chapter 9.1 --- STUDIO CASE STUDIES / Chapter 9.2 --- RELOCATABLE ARCHITECTURE CASE STUDIES
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A feasibility study and business proposal for a new comer of CT2 cordless telephone operating company /Liu, Van-chee. January 1900 (has links)
Thesis (M.B.A.)--University of Hong Kong, 1992.
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5G Sports – tragbare Technologiedemonstratoren im taktilen InternetLüneburg, Lisa-Marie, Papp, Emese, Krzywinski, Jens 03 January 2020 (has links)
Der fünfte Mobilfunkstandard 5G wird zukünftig die Übertragung großer Datenmengen auch über weite Strecken nahezu in Echtzeit ermöglichen. Diese neue, praktisch latenzfreie Kommunikationstechnologie erlaubt einen von zeit- und ortsunabhängigen Austausch von Fähigkeiten und Kompetenzen zwischen Menschen und Maschinen. Damit werden haptisches Feedback über weite Entfernungen (taktiles Internet) und als Anwendung dessen neue Formen des räumlich verteilten Kooperierens und Lernens (Internet der Fähigkeiten und Kompetenzen) möglich. Das Exzellenzcluster CeTI der TU Dresden setzt mit seiner Forschung genau an dieser Stelle an: Eine Vielzahl möglicher interaktiver Anwendungen im Konsumenten-, aber auch im professionellen Bereich ist denkbar. In einer interdisziplinären Vorstudie des Technisches Designs und des 5G Lab Germany wurden mögliche Einsatzfelder identifiziert und durch Demonstratoren erlebbar gemacht. Als ein Anwendungsbereich wurde der Leistungssport identifiziert. Da Disziplin, hohe körperliche Belastung und Perfektion im Bewegungsablauf von professionellen Sportlern über einen langen Zeitraum abverlangt wird, bringt der Bereich ein hohes Potenzial und Akzeptanz mit sich, um effizientere Trainingsmethoden mit Hilfe von cyber-physischen Systemen zu entwickeln. Eine wesentliche Fragestellung der Vorstudie war außerdem zu untersuchen, inwieweit Demonstratoren das Erleben verschiedener Ebenen einer abstrakten Technologie ermöglichen können. In einer Primärstudie, die als Beobachtungen während einer Messeveranstaltung des 5G Summit und weiteren öffentlichen Ausstellungen in Dresden 2018 durchgeführt wurden, konnten hierzu erste Erkenntnisse gewonnen werden.
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License-free communication using digital mobile radio standards and spread spectrumMcQuay, Colter James Alexander 17 July 2019 (has links)
The concept of using spread spectrum and open radio standards to provide license-free, short range Peer-to-Peer (P2P) communication is explored. This research makes use of the Time Compression Overlap Add (TC-OLA) algorithm to transparently spread the spectrum of the Digital Mobile Radio (DMR) standard; this allows for reuse of existing hardware, software, and expertise relating to this well established protocol. Initial high level hardware designs of a communication device established the need to implement a proof of concept system which could be validated against Radio Frequency (RF) regulations. This proof of concept system was constructed using a hardware implementation of DMR processed through custom TC-OLA blocks in GNU Radio (GR). A spectral and performance analysis of this system was performed, showing that this approach has several benefits over existing license free communication options. / Graduate / 2020-07-11
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Connectivity monitoring in mobile packet radio networksHluchyj, Michael Gene January 1979 (has links)
Thesis (Elec.E)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Michael Gene Hluchyj. / Elec.E
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Multi-access in packet radio networksArıkan, Erdal January 1982 (has links)
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Includes bibliographical references. / by Erdal Arikan. / M.S.
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