76 research outputs found
Application of advanced on-board processing concepts to future satellite communications systems: Bibliography
Abstracts are presented of a literature survey of reports concerning the application of signal processing concepts. Approximately 300 references are included
Application of advanced on-board processing concepts to future satellite communications systems
An initial definition of on-board processing requirements for an advanced satellite communications system to service domestic markets in the 1990's is presented. An exemplar system architecture with both RF on-board switching and demodulation/remodulation baseband processing was used to identify important issues related to system implementation, cost, and technology development
Joint coding and modulation designs for bandlimited satellite channels
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1981.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.Includes bibliographical references.by Joseph Y. N. Hui.M.S
Secure mobile radio communication over narrowband RF channel.
by Wong Chun Kau, Jolly.Thesis (M.Phil.)--Chinese University of Hong Kong, 1992.Includes bibliographical references (leaves 84-88).ABSTRACT --- p.1ACKNOWLEDGEMENT --- p.3Chapter 1. --- INTRODUCTION --- p.7Chapter 1.1 --- Land Mobile Radio (LMR) CommunicationsChapter 1.2 --- Paramilitary Communications SecurityChapter 1.3 --- Voice Scrambling MethodsChapter 1.4 --- Digital Voice EncryptionChapter 1.5 --- Digital Secure LMRChapter 2. --- DESIGN GOALS --- p.20Chapter 2.1 --- System Concept and ConfigurationChapter 2.2 --- Operational RequirementsChapter 2.2.1 --- Operating conditionsChapter 2.2.2 --- Intelligibility and speech qualityChapter 2.2.3 --- Field coverage and transmission delayChapter 2.2.4 --- Reliability and maintenanceChapter 2.3 --- Functional RequirementsChapter 2.3.1 --- Major system featuresChapter 2.3.2 --- Cryptographic featuresChapter 2.3.3 --- Phone patch facilityChapter 2.3.4 --- Mobile data capabilityChapter 2.4 --- Bandwidth RequirementsChapter 2.5 --- Bit Error Rate RequirementsChapter 3. --- VOICE CODERS --- p.38Chapter 3.1 --- Digital Speech Coding MethodsChapter 3.1.1 --- Waveform codingChapter 3.1.2 --- Linear predictive codingChapter 3.1.3 --- Sub-band codingChapter 3.1.4 --- VocodersChapter 3.2 --- Performance EvaluationChapter 4. --- CRYPTOGRAPHIC CONCERNS --- p.52Chapter 4.1 --- Basic Concepts and CryptoanalysisChapter 4.2 --- Digital Encryption TechniquesChapter 4.3 --- Crypto SynchronizationChapter 4.3.1 --- Auto synchronizationChapter 4.3.2 --- Initial synchronizationChapter 4.3.3 --- Continuous synchronizationChapter 4.3.4 --- Hybrid synchronizationChapter 5. --- DIGITAL MODULATION --- p.63Chapter 5.1 --- Narrowband Channel RequirementsChapter 5.2 --- Narrowband Digital FMChapter 5.3 --- Performance EvaluationChapter 6. --- SYSTEM IMPLEMENTATION --- p.71Chapter 6.1 --- Potential EMC ProblemsChapter 6.2 --- Frequency PlanningChapter 6.3 --- Key ManagementChapter 6.4 --- Potential Electromagnetic Compatibility (EMC) ProblemsChapter 7. --- CONCLUSION --- p.80LIST OF ILLUSTRATIONS --- p.81REFERENCES --- p.82APPENDICES --- p.89Chapter I. --- Path Propagation Loss(L) Vs Distance (d)Chapter II. --- Speech Quality Assessment Tests performedby Special Duties Unit (SDU
A likelihood ratio analysis of digital phase modulation
Bibliography: p. 180-188.Although the likelihood ratio forms the theoretical basis for maximum likelihood (ML) detection in coherent digital communication systems, it has not been applied directly to the problem of designing good trellis-coded modulation (TOM) schemes. The remarkably simple optimal receiver of minimum shift keying (MSK) has been shown to result from the mathematical simplification of its likelihood ratio into a single term. The log-likelihood ratio then becomes a linear sum of metrics which can be implemented as a so-called simplified receiver, comprising only a few adders and delay elements. This thesis project investigated the possible existence of coded modulation schemes with similarly simplifying likelihood ratios, which would have almost trivially simple receivers compared to the Viterbi decoders which are typically required for maximum likelihood sequence estimation (MLSE). A useful notation, called the likelihood transform, was presented to aid the analysis of likelihood ratios. The work concentrated initially on computer-aided searches, first for trellis codes which may give rise to simplifying likelihood ratios for continuous phase modulation (CPM), and then for mathematical identities which may aid in the simplification of generic likelihood ratios for equal-energy modulation. The first search yielded no simplified receivers, and all the identities produced by the second search had structures similar to the likelihood ratio of MSK. These observations prompted a formal proof of the non-existence of simplified receivers which use information from more than two symbols in their observation period. This result strictly bounds the error performance that is possible with a simplified receiver. It was also proved that simplified receivers are only optimal for modulation schemes which use no more than two pairs of antipodal signals, and that only binary modulation schemes can have simplified receivers which use information from all the symbols in their observation period
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Integration of unidirectional technologies into wireless back-haul architecture
This thesis was submitted for the degree of Docter of Philosophy and awarded by Brunel University.Back-haul infrastructures of today's wireless operators must support the triple-play services demanded by the market or regulatory bodies. To cope with increasing capacity demand, the EU FP7 project CARMEN has developed a cost-effective heterogeneous
multi-radio wireless back-haul architecture, which may also leverage the native multicast
capabilities of broadcast technologies such as DVB-T to off-load high-bandwidth broadcast
content delivery. However, the integration of such unidirectional technologies into a packet-switched architecture requires careful considerations. The contribution of this thesis is the investigation, design and evaluation of protocols and mechanisms facilitating the integration of such unidirectional technologies into the wireless
back-haul architecture so that they can be configured and utilized by the spectrum and
capacity optimization modules. This integration mainly concerns the control plane and, in particular, the aspects related to resource and capability descriptions, neighborhood, link and Multi Protocol Label Switching (MPLS) Label-Switched Path (LSP) monitoring, unicast and multicast LSP signalling as well as topology forming and maintenance. During the course of this study we have analyzed the problem space, proposed solutions to the resulting research questions and evaluated our approach. Our results show that the now Unidirectional Technology (UDT)-aware architecture can readily consider
Unidirectional Technologies (UDTs) to distribute, for example, broadcast content
Joint University Program for Air Transportation Research, 1990-1991
The goals of this program are consistent with the interests of both NASA and the FAA in furthering the safety and efficiency of the National Airspace System. Research carried out at the Massachusetts Institute of Technology (MIT), Ohio University, and Princeton University are covered. Topics studied include passive infrared ice detection for helicopters, the cockpit display of hazardous windshear information, fault detection and isolation for multisensor navigation systems, neural networks for aircraft system identification, and intelligent failure tolerant control
The Telecommunications and Data Aquisition Report
Tracking and ground-based navigation techniques are discussed in relation to DSN advanced systems. Network data processing and productivity are studied to improve management planning methods. Project activities for upgrading DSN facilities are presented
The telecommunications and data acquisition report
Deep Space Network operations, engineering, and implementation are reported. Developments in Earth-based radiotechnology as applied to other research programs in the fields of Geodynamics, Astrophysics, and programs related to radio searchers (instrumentation and methods) in extraterrestrial areas in the microwave region of the electromagnetic spectrum are also presented
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