Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 60 for “"mobile radio"”.
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Noise blanker for land mobile radio systems
The field of private mobile radio systems (taxis, police, emergency services, dispatch systems etc.) is undergoing accelerated change and deregulation. More users, demanding more services with better quality, are squeezed into the same bandwidth. However, noise and impulsive noise levels on the …
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Fade durations in satellite-path mobile radio propagation
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 …
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Low bit-rate speech encoding for digital mobile radio
… is the result of growing demand on the available radio bandwidth for mobile communications both for military purposes and for the public sector. To meet this growing demand it is required that the available bandwidth be utilized in the most economic way to accommodate more services. Two low …
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Security in Packet-Switched Land Mobile Radio Backbone Networks
… lower-cost technology and services, many land mobile radio (LMR) operators have begun transitioning from circuit-switched to packet-switched backbone networks to handle their future communication needs. Due to the unique demands of packet-switched backbone networks for LMR, it may not be wise …
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Design Considerations in a Modern Land Mobile Radio System
Modern Land Mobile Radio has the potential for large growth in the near future. Current regulations have set the stage for a required transition to more spectrally efficient technologies. While several organizations are working to ease this transition, there still remain many details and feature …
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An Integrated voice-data transmission system for private mobile radio
Private mobile radio services have experienced for a number of years congestion of the available spectrum. Although the release of Band III has contributed significantly to alleviating the spectrum shortage, it will however, not be sufficient to accommodate the projected growth in private mobile …
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Analysis and simulation of computer controlled cellular mobile radio systems
Cellular mobile radio systems will be of increasing importance in the future. This thesis describes research work concerned with the teletraffic capacity and the canputer control requirements of such systems. The work involves theoretical analysis and experimental investigations using digital …
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The re-engineering of VHF mobile radio services in the UK
… considerations necessary for the design of VHF mobile radio systems, and is directed particularly at the requirements of the emergency services of the United Kingdom. It was occasioned by an international regulatory decision to re-allocate part of their existing operating frequencies. This work …
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A land mobile radio coverage area prediction model for New Zealand
… step in the development of a nationwide land mobile coverage area prediction model for New Zealand. The most suitable approach is shown to be a computer-based method which includes corrections for both environmental and terrain features. Extensive field trials performed in Auckland at 76 and …
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Efficiency improvements to the Groupe Special Mobile (GSM) digital mobile radio system
Groupe Spécial Mobile (GSM) has been developed as the pan-European second generation of digital mobile systems. GSM operates in the 900 MHz frequency band and employs digital technology instead of the analogue technology of its predecessors. Digital technology enables the GSM system to operate in …
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Performance of GMSK and 7/4-DQPSK Modulations in Land Mobile Radio Channels
… that provide telephone communication service to mobile users have experienced a rapid growth during the last five years. The current cellular systems are analog in nature. These systems employ frequency modulation. As the spectrum gets crowded, bandwidth efficient digital systems will find …
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Dynamic range of analog fiber optic links used in microcellular mobile radio applications
… of analog fiber optic links for microcellular mobile radio communications has been the focus of considerable research recently. These systems have the advantages relative to coaxial cable of low noise and enormous bandwidth. Analog subcarrier multiplexing techniques are used for transmitting …
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Investigation of a Packet-Switched Inter-System Interface for Land Mobile Radio Systems
Traditionally, and up to this date, Land Mobile Radio (LMR) systems have been interconnected via leased lines and microwave links across circuit-switched networks. With the recent deployment of digital LMR standards such as the Association of Public and Communications Officials (APCO) Project 25 …
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Simulation of adaptive equalization in two-ray, SIRCIM, and SMRCIM mobile radio channels
… degraded by intersymbol interference in radio communication. This thesis considers the following structures: the linear transversal equalizer (LTE), the decision feedback equalizer (DFE), the lattice equalizer, and the maximum likelihood sequence estimation (MLSE) equalizer. Least mean …
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Coherence bandwidth characterisation for indoor mobile radio microcells at microwave and millimetre wave frequencies
… results of the coherence bandwidth of indoor mobile radio microcells at 11 GHz and 62.4 GHz. Furthermore, the influence of the antennas radiation patterns and the effect of furniture on the value of the coherence bandwidth has been investigated.<br/><br/>A two branch frequency diversity system …
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Design of mobile radio communication system at millimetre-waves and BER measurements for indoor environments
… to estimate the system performance in indoor mobile channels is necessary for future system design and applications.<br/><br/>The studies reported in this thesis are concerned with the design of a digitally modulated broadband system at 60 GHz and the estimation of Bit Error Rate (BER) …
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Evaluation of several techniques for enhancing speech degraded by additive noise in mobile radio environments
… enhancing speech degraded by additive noise in mobile cellular communications. The primary goal of this multi-stage study was to examine adaptive noise cancellation techniques in which one microphone is used to measure the speech plus noise signal and another microphone is used to form an …
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