Dissertations / Theses: 'Radio (telecommunication system)'

1

Sharkey, Jeffrey Allen. "Automated radio network design using ant colony optimization." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/sharkey/SharkeyJ0508.pdf.

Full text

Abstract:

Radio networks can provide reliable communication for rural intelligent transportation systems (ITS). Engineers manually design these radio networks by selecting tower locations and equipment while meeting a series of constraints such as coverage, bandwidth, maximum delay, and redundancy, all while minimizing network cost. As network size and constraints grow, the design process can quickly become overwhelming. In this thesis we model the network design problem (NDP) as a generalized Steiner tree-star (GSTS) problem. Any solution to the minimum Steiner tree (MST) problem on a constructed GSTS graph will directly identify the tower locations and equipment needed to build the network at an optimal cost. The direct MST solution can only satisfy coverage constraints. Because the MST problem is known to be NP-hard, our research applies ant colony optimization (ACO) to find near-optimal MST solutions. Using ACO also allows us to meet bandwidth, maximum delay, and redundancy constraints. We verify that our approach finds near-optimal designs by comparing it against a 2-approximation algorithm in several different scenarios.

APA, Harvard, Vancouver, ISO, and other styles

2

Kyösti, P. (Pekka). "Radio channel modelling for 5G telecommunication system evaluation and over the air testing." Doctoral thesis, Oulun yliopisto, 2018. http://urn.fi/urn:isbn:9789526219035.

Full text

Abstract:

Abstract This thesis discusses radio channel modelling for evolving radio access and of using the models in practice in a setup for radiated testing of radio devices. New telecommunication systems are constantly being developed to address continuously increasing wireless communication needs. The first pieces of intensively developed fifth generation (5G) networks and devices are planned to be available, in some form, approximately by 2020. An interesting feature of 5G concerning propagation and consequently channel modelling, is the expected utilization of frequencies clearly higher than the legacy cellular systems. This work aims to define a channel model for the simulated evaluation of the coming 5G systems. New requirements for the channel model are identified and addressed. Further, over the air (OTA) testing of 5G devices in fading conditions is examined and a new setup is proposed. The test environment aims to reconstruct a time variant electromagnetic (EM) field around a device under test (DUT) considering the spatial, polarimetric, Doppler, and delay dispersion characteristics specified by the target channel model. Components and key design parameters of the setup are designated. It was found that the proposed map-based channel model is capable of fulfilling the identified requirements. Furthermore, the simulations indicate that the state-of-the-art geometry-based stochastic channel model (GSCM) may give over-optimistic multi-user MIMO (MU-MIMO) performance in an urban micro-cellular environment. The sectored OTA concept was shown appropriate for device testing. Key parameters, such as the physical dimensions of the multi-probe anechoic chamber (MPAC) OTA configuration and the number of active probes, were determined by simulations. The 3GPP is the main forum working towards 5G standards. A channel model for 5G evaluations has recently (2016) been specified. The base-line model is a GSCM inherited from the 4G models. However, the author expects that the proposed map-based models will gain popularity in the future, despite the current widespread use of GSCMs. In the 3GPP working group RAN4 (Radio performance and protocol aspects) the test methods for 5G user equipment (UE) are currently (2017) under investigation. The proposed sectored MPAC method has been contributed to and is under consideration in 3GPP. Even if it is not approved for UE testing, the author expects it to be useful for performance testing of base stations (BSs)
Tiivistelmä Tämän väitöskirjan sisältönä on radiokanavamallinnus langattomia tiedonsiirtojärjestelmiä varten ja lisäksi mallien käyttöönottoa tulevien radiolaitteiden säteilevässä testauksessa. Uusia tietoliikennejärjestelmiä kehitetään jatkuvasti, yhtä lailla jatkuvasti kasvavien tiedonsiirtotarpeiden tyydyttämiseksi. Ensimmäisten verkkojen ja päätelaitteiden pitäisi olla saatavilla tulevaan viidennen sukupolven (5G) järjestelmään vuoden 2020 tietämillä. Työn tarkoituksena on määritellä kanavamalli 5G-järjestelmän simulointeja varten ja sitä edeltäen tunnistaa kanavamallin vaatimukset. Lisäksi tutkimuksen aiheena on 5G-laitteiden säteilevä (OTA) testaus häipyvässä radiokanavassa ja uuden testijärjestelmän määrittely tätä tarkoitusta varten. Ehdotetun testijärjestelmän keskeisenä toimintona on halutun sähkömagneettisen (EM) kentän tuottaminen testattavan laitteen ympärille. EM-kentän pitää olla kanavamallin mukainen ja toteuttaa sen häipymä-, tila-, polarisaatio-, doppler- ja viiveominaisuudet. Testijärjestelmän komponentit ja tärkeimmän suunnitteluparametrit pyritään selvittämään tässä työssä. Tutkimuksessa havaittiin, että ehdotettu karttapohjainen kanavamalli toteuttaa 5G-mallille asetetut vaatimukset. Simuloinnit osoittavat myös, että tyypillisessä kaupunkiympäristössä suosittu GSCM-malli yliarvioi kanavan kapasiteetin monen käyttäjän MIMO-tekniikka käytettäessä. Lisäksi osoitettiin sektoroidun OTA-järjestelmän, jossa hyödynnetään useita antenneja, radiokanavaemulaattoria sekä radiokaiutonta huonetta (MPAC), käyttökelpoisuus 5G-laitteiden testaukseen. Kyseisen testausjärjestelmän parametrit määriteltiin. 3GPP on tärkein foorumi, jolla 5G-standardeja luodaan. Siellä on hiljattain (2016) sovittu 5G-simulointeja varten kanavamalli, joka ei ole tässä työssä ehdotetun kaltainen. Standardoitu malli on tyypiltään GSCM ja se on johdettu suoraan edellisen sukupolven (4G) kanavamallista. Kirjoittaja olettaa tästä GSCM:n nykyisestä vahvasta asemasta huolimatta, että ehdotettu karttapohjainen kanavamalli lisää suosiotaan tulevaisuudessa. Parhaillaan (2017) on 3GPP:n RAN4-työryhmässä käynnissä 5G-päätelaitteiden (UE) testimenetelmien määrittelyvaihe. Väitöskirjassa tutkittua sektoroitua MPAC-menetelmää on ehdotettu työryhmälle standardoitavaksi. Vaikka mainittua menetelmää ei siellä standardoitaisikaan UE-testaukseen, niin voidaan olettaa menetelmän olevan hyödyllinen erityisesti tukiasemien säteilevään testaukseen

APA, Harvard, Vancouver, ISO, and other styles

3

Smuts, Matthys. "Software modem for a software defined radio system." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/1985.

Full text

Abstract:

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2007.
The use of older and slower protocols has become increasingly difficult to justify due to the rapid pace at which telecommunications are advancing. To keep up to date with the latest technologies, the communications system must be designed to accommodate the transparent insertion of new communications standards in all the stages of a system. The system should, however, also remain compatible with the older standards so as not to demand an upgrade of the older systems. The concept of a software defined radio was introduced to overcome these problems. In a software defined radio system, the functionality of the communications system is defined in software, which removes the the need for alterations to the hardware during technology upgrade. To maintain interoperatibilty, the system must be based on a standardised architecture. This would further allow for enhanced scalability and provide a plug-andplay feature for the components of the system. In this thesis, generic signal processing software components are developed to illustrate the creation of a basic software modem that can be parameterised to comply fully, or partially, to various standards.

APA, Harvard, Vancouver, ISO, and other styles

4

Larsson, Joachim. "CPU Load Control of LTE Radio Base Station." Thesis, Linköpings universitet, Reglerteknik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-123499.

Full text

Abstract:

A radio base station (RBS) may become overloaded if too many mobile devices communicate with it at the same time. This could happen at for instance sport events or in the case of accidents. To prevent CPU overload, the RBS is provided with a controller that adjusts the acceptance rate, the maximum number of connection requests that can be accepted per time interval. The current controller is tuned in real radio base stations and the procedure is both time consuming and expensive. This, combined with the fact that the mobile data usage is predicted to increase puts more pressure on today's system. Thus, there is a need to be able to simulate the system in order to suggest an alternative controller. In this thesis, an implementation of the system is developed in Matlab in order to simulate the RBS system load control behaviour. A CPU load model is estimated using system identification. The current version of the CPU load controller and an alternative PI CPU load controller are implemented. Both are evaluated on different test cases and this shows that it is possible to increase the performance of the system with the alternative CPU load controller, both in terms of lower amount of rejected connection requests and decreased CPU load overshoot.

APA, Harvard, Vancouver, ISO, and other styles

5

Labuschagne, Adriaan S. "The design of a telemetry system for Grumeti Reserves /." Thesis, Link to the online version, 2006. http://hdl.handle.net/10019.1/2542.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Aburawi, Abdulrahman, and Sarija Salic. "Emergency Communication." Thesis, Malmö högskola, Fakulteten för teknik och samhälle (TS), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-20568.

Full text

Abstract:

Even in the 21st century, modern communication technology is still affected by natural disasters and political turmoil which threaten people’s lives and make the internet or mobile phone networks unavailable for use. This work uses systems theory which resulted in a proof of concept system that uses shortwave radio technology to provide a one-way communication system. A message a user writes on their smartphone, which is connected to a small pre-set transmitter, is sent out to a receiver in another part of the world where the message can then be posted on the internet. This system is a cheaper alternative to other shortwave radio transmitters, and has potential for improvement.

APA, Harvard, Vancouver, ISO, and other styles

7

Senol, Gokberk. "Performance Analysis Of A Digital Communication System On Sea Platforms." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12615134/index.pdf.

Full text

Abstract:

The transmission rate and reliability are the most crucial elements of a communication system on sea platforms. In this thesis, the performance of a high speed and reliable communication system that can be used on ship to ship sea platforms will be evaluated. The two ray channel model is used in order to characterize the channel considering the refraction and reflection. Using the channel model, the path loss and the Shannon channel capacities are obtained for different systems. In order to increase the system performance, frequency diversity technique is used and a detailed comparison of diversity combining techniques is provided. As an alternative to Shannon channel capacity, cut off rate analysis is considered to get more realistic results about the rate of the communication system in that it takes modulation into account and the results are compared with the channel capacity. Block fading model and jamming effects on the achievable rate of the system is considered for different linear modulation techniques. Finally, an OFDM system design is given as an example using the tools obtained in this work.

APA, Harvard, Vancouver, ISO, and other styles

8

Tanyer, Fatma Muge. "Design Of Log-periodic Dipole Array Feed And Wide Band Reflector Antenna System." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/12605948/index.pdf.

Full text

Abstract:

The introduction of broadband systems to communication and radar technologies has demanded the design of broadband antennas. In this thesis, broadband log-periodic dipole antennas and reflector antennas are investigated. A dual polarized log-periodic dipole antenna and a reflector antenna are designed and analyzed within the frequency band of 0.4-18 GHz. Basic theory and calculations about mutual coupling between the linear antenna elements are given. The currents at the bases of dipoles of the log-periodic antenna are found and these currents are used as inputs for the design of the reflector antenna. After the simulations made with MATLABÒ
and FORTRAN, a prototype single polarized log-periodic antenna is produced. Developments on the prototype antenna are performed, both to improve the electrical characteristics of the antenna and to make the final design realizable. After the performance of the single polarized log-periodic antenna is found satisfactory, dual polarized antenna is produced. Performances of both single and dual polarized log-periodic antennas are measured in the anechoic chamber at ASELSAN®
Inc. After the measurements of the antenna, using the currents at the bases of the dipoles, a reflector antenna is designed using &ldquo
MIR&rdquo
program written in FORTRAN, which is based on physical optics method. A method to calculate the aperture blockage of the reflector is developed. Simulation results of reflector antenna are given.

APA, Harvard, Vancouver, ISO, and other styles

9

Kilicoglu, Nezaket. "Construction Of An Experimental Radar System." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612760/index.pdf.

Full text

Abstract:

In this thesis, an Experimental Radar System is designed and constructed for use in experimental radar studies such as clutter measurement and target detection, both in the laboratory and outdoor. COTS laboratory equipments are utilized as hardware elements of the radar and MATLAB is used as signal processing and user interface software tool. Vector signal generator (as transmitter), spectrum analyzer with vector signal analysis (as receiver), a high power amplifier, a low noise amplifier, horn antennas and a computer are the hardware units of the system. Various transmit signals are generated and pulse Doppler processing is performed at the receiver side. The system is controlled through the user interface which runs on a PC.

APA, Harvard, Vancouver, ISO, and other styles

10

Kurekli, Kenan. "System Parameter Adaptation Based On Image Metrics For Automatic Target Detection." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604966/index.pdf.

Full text

Abstract:

Automatic object detection is a challenging field which has been evolving over decades. The application areas span many domains such as robotics inspection, medical imaging, military targeting, and reconnaissance. Some of the most concentrated efforts in automatic object detection have been in the military domain, where most of the problems deal with automatic target detection and scene analysis in the outdoors using a variety of sensors. One of the critical problems in Automatic Target Detection (ATD) systems is multiscenario adaptation. Most of the ATD systems developed until today perform unpredictably i.e. perform well in certain scenarios, and poorly in others. Unless ATD systems can be made adaptable, their utility in battlefield missions remains questionable. This thesis describes a methodology that adapts parameterized ATD systems with image metrics as the scenario changes so that ATD system can maintain better performance. The methodology uses experimentally obtained performance models, which are functions of image metrics and system parameters, to optimize performance measures of the ATD system. Optimization is achieved by adapting system parameters with incoming image metrics based on performance models as the system works in field. A simple ATD system is also proposed in this work to describe and test the methodology.

APA, Harvard, Vancouver, ISO, and other styles

11

Hsueh, Yu-Ting. "Frontiers of optical networking technologies: millimeter-wave radio-over-fiber and 100g transport system for next-generation high-data-rate applications." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43681.

Full text

Abstract:

The enabling technologies and the issues of next-generation millimeter-wave wireless access network and 100G long-haul optical transport network were developed and identified. To develop a simple and cost-effective millimeter-wave optical-wireless system, all-round research on the technical challenges of optical millimeter-wave generation, transmission impairments compensation, and simple base station design were discussed. Several radio-over-fiber systems were designed to simultaneously deliver multi-band wireless services on a single optical infrastructure, enabling converged system control and quality maintenance in central office. For the 100G optical transport network, the issues related to successful implementations of transmitter, fiber link, and receiver of a 112-Gb/s polarization-division multiplexing-quadrature phase shift keying (PDM-QPSK) system were comprehensively explored. The experimental results based on the constructed 112-Gb/s testbed indicated that careful dispersion management can effectively increase nonlinearity tolerance. Furthermore, the special emphasis on the two impairments of the 100G network with reconfigurable optical add-drop multiplexers: passband narrowing and in-band crosstalk, was studied. The results demonstrated that these impairments can be readily predicted with proper experimental and simulation efforts.

APA, Harvard, Vancouver, ISO, and other styles

12

Kasak, Kerem. "An Implementation And Algorithm Development For Uwb Through The Wall Imaging System." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12609025/index.pdf.

Full text

Abstract:

The feasibility of Ultra Wide Band (UWB) through the wall surveillance system is studied in this thesis. The transmitter and receiver architectures are discussed and an experimental set-up is constructed to verify the theory of UWB sensing. The constructed system has 80 mW peak, 6 uW average transmit power and 500 kHz PRF and a range resolution better than 1 cm. Using the experimental set-up, two problems are examined. The first problem is the respiration rate detection problem. It has been shown that the respiration rate can be accurately estimated and the signs of vital activity can be determined behind the wall. The second problem studied in this thesis is the through the wall imaging problem. The imaging system is based on the construction of a synthetic aperture by sliding the transmit-receive antenna pair along the cross range direction. The cross range resolution is improved by applying a migration algorithm to the collected data. It has been shown that imaging of a scene 8 meters in range, behind a wall of 20 cm thickness is possible with the available power.

APA, Harvard, Vancouver, ISO, and other styles

13

Salmon, Brian P. "Optimizing LDPC codes for a mobile WiMAX system with a saturated transmission amplifier." Pretoria : [s.n.], 2008. http://upetd.up.ac.za/thesis/available/etd-01262009-160431/.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Yuksekkaya, Mehmet. "Implementation And Performance Analysis Of The Dvb-t Standard System." Master's thesis, METU, 2005. http://etd.lib.metu.edu.tr/upload/2/12606904/index.pdf.

Full text

Abstract:

Terrestrial Digital Video Broadcasting (DVB-T) is a standard for wireless broadcast of MPEG-2 video. DVB-T is based on channel coding algorithms and uses Orthogonal Frequency Division Multiplexing (OFDM) as a modulation scheme. In this thesis, we have implemented the standard of ETSI EN 300 744 for Digital Video Broadcasting in MATLAB. This system is composed of the certain blocks which include OFDM modulation, channel estimation, channel equalization, frame synchronization, error-protection coding, to name a few of such blocks. We have investigated the performance of the complete system for different wireless broadcast impairments. In this performance analysis, we have considered Rayleigh fading multi-path channels with Doppler shift and framing synchronization errors and obtained the bit error rate (BER), and channel minimum square error performances versus different maximum Doppler shift values, different channel equalization techniques and different channel estimation algorithms. Furthermore, we have investigated different interpolations methods for the interpolation of channel response. It is shown that minimum mean-square error (MMSE) type equalization has a better performance in symbol estimation compared to zero forcing (ZF) equalizer. Also linear interpolation in time and low pass frequency interpolation, for time frequency interpolation of channel response can be used for practical application.

APA, Harvard, Vancouver, ISO, and other styles

15

Aburas, Akram. "Operating System Based Perceptual Evaluation of Call Quality in Radio Telecommunications Networks. Development of call quality assessment at mobile terminals using the Symbian operating system, comparison with traditional approaches and proposals for a tariff regime relating call charging to perceived speech quality." Thesis, University of Bradford, 2012. http://hdl.handle.net/10454/5479.

Full text

Abstract:

Call quality has been crucial from the inception of telecommunication networks. Operators need to monitor call quality from the end-user's perspective, in order to retain subscribers and reduce subscriber 'churn'. Operators worry not only about call quality and interconnect revenue loss, but also about network connectivity issues in areas where mobile network gateways are prevalent. Bandwidth quality as experienced by the end-user is equally important in helping operators to reduce churn. The parameters that network operators use to improve call quality are mainly from the end-user's perspective. These parameters are usually ASR (answer seizure ratio), PDD (postdial delay), NER (network efficiency ratio), the number of calls for which these parameters have been analyzed and successful calls. Operators use these parameters to evaluate and optimize the network to meet their quality requirements. Analysis of speech quality is a major arena for research. Traditionally, users' perception of speech quality has been measured offline using subjective listening tests. Such tests are, however, slow, tedious and costly. An alternative method is therefore needed; one that can be automatically computed on the subscriber's handset, be available to the operator as well as to subscribers and, at the same time, provide results that are comparable with conventional subjective scores. QMeter® 'a set of tools for signal and bandwidth measurement that have been developed bearing in mind all the parameters that influence call and bandwidth quality experienced by the end-user' addresses these issues and, additionally, facilitates dynamic tariff propositions which enhance the credibility of the operator. This research focuses on call quality parameters from the end-user's perspective. The call parameters used in the research are signal strength, successful call rate, normal drop call rate, and hand-over drop rate. Signal strength is measured for every five milliseconds of an active call and average signal strength is calculated for each successful call. The successful call rate, normal drop rate and hand-over drop rate are used to achieve a measurement of the overall call quality. Call quality with respect to bundles of 10 calls is proposed. An attempt is made to visualize these parameters for better understanding of where the quality is bad, good and excellent. This will help operators, as well as user groups, to measure quality and coverage. Operators boast about their bandwidth but in reality, to know the locations where speed has to be improved, they need a tool that can effectively measure speed from the end-user's perspective. BM (bandwidth meter), a tool developed as a part of this research, measures the average speed of data sessions and stores the information for analysis at different locations. To address issues of quality in the subscriber segment, this research proposes the varying of tariffs based on call and bandwidth quality. Call charging based on call quality as perceived by the end-user is proposed, both to satisfy subscribers and help operators to improve customer satisfaction and increase average revenue per user. Tariff redemption procedures are put forward for bundles of 10 calls and 10 data sessions. In addition to the varying of tariffs, quality escalation processes are proposed. Deploying such tools on selected or random samples of users will result in substantial improvement in user loyalty which, in turn, will bring operational and economic advantages.

APA, Harvard, Vancouver, ISO, and other styles

16

Rootman, Adriaan Cornelius. "Development of a remote wireless monitoring system for large farms." Thesis, Cape Peninsula University of Technology, 2012. http://hdl.handle.net/20.500.11838/1173.

Full text

Abstract:

Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Electrical Engineering at the Cape Peninsula University of Technology, 2012
This research project addresses the unique challenges of extensive farming in terms of monitoring and controlling remote equipment or events. Poorly maintained roads and escalating fuel costs increase difficulty of farming and the time spent on physically monitoring remote sites further reduces financial yields. The research showed that there are very few solutions that implement wireless or electronic technology to overcome the challenges associated with these isolated and arid areas and that a low-cost, long range wireless telemetry solution that is easy to use would be beneficial for the extensive farming industry. It was therefore the aim of this project to develop a remote monitoring and controlling solution that implements wireless technology to convey information of activities around the farm utilising electronic means. To be able to successfully develop a wireless telemetry solution that will accurately meet the needs of this specific sector of industry, market research was conducted. To guide the research, the QFD (quality function deployment) process for product development has been implemented. The research consisted out of various aspects including a survey, financial considerations and international comparisons. The research also aided in the understanding of the day-to-day activities and also the physical parameters of extensive farms. Also, currently available technologies and products were evaluated to establish whether similarities exist that will aid in the development of a new product. The development process was based on the results obtained in the market research and resulted in a wireless telemetry solution that overcame all the design challenges and proved to be technically feasible, successfully addressing the application requirements. Zigbee technology was utilized for wireless communication because it provided an off-the-shelf solution with a number of readily available development platforms from various technology providers. A communication range of up to 6 kilometres with a transmitted power of 11dBm was achieved for point-to-point communication and a mesh network topology has been implemented for even longer range and complete coverage on farms. Various types of measurements have been catered for, with custom-designed instrumentation which enabled measurements such as water levels, movement and analogue signals. Also, a basic user interface was developed to enable the user to monitor or control the equipment or events remotely from a personal computer, locally or even over the internet. The results of this research project showed that by carefully selecting available technologies and understanding the application, it is possible to develop a solution that addresses the monitoring and controlling needs associated with extensive farming. The wireless telemetry system that was developed resulted in a saving equal to 10% of the total expenses of the farms per year. The telemetry system is therefore a financially feasible solution with a payback period of less than 1 year and far below the initial estimated budget. Without the need to physically monitoring equipment and events, an increase in productivity and the expansion of the overall enterprise is a further benefit added unto the monetary savings. In addition to the financial benefits of implementing new wireless technology, this is an opportunity to contribute to a cleaner and more sustained future as a legacy for the next generation by reducing the carbon footprint of the farm.

APA, Harvard, Vancouver, ISO, and other styles

17

Van, Dam Catharina Johanna Henrica. "Intelligent control of radio communication system." Thesis, Queen Mary, University of London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299184.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Wang, Li. "TDMA digital mobile radio transmission system." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240335.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Shepherd, Mark. "Radio channel assignment." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288047.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Wassell, Ian J. "Digital mobile radio." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.277683.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Nappier, Jennifer M. "An FPGA Abstraction Layer for the Space Telecommunications Radio System." Case Western Reserve University School of Graduate Studies / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1227033556.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Atefi, A. "An investigation of radio wave propagation in mobile radio frequency bands." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354537.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Kilic, Hasan Huseyin. "Design And Fabrication Of A High Gain, Broadband Microwave Limiting Amplifier Module." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613616/index.pdf.

Full text

Abstract:

Microwave limiting amplifiers are the key components of Instantaneous Frequency Measurement (IFM) systems. Limiting amplifiers provide constant output power level in a wide input dynamic range and over a broad frequency band. Moreover, limiting amplifiers are high gain devices that are used to bring very low input power levels to a constant output power level. Besides, limiting amplifiers are required to provide minimum small signal gain ripple in order not to reduce the sensitivity of the IFM system over the operating frequency band. In this thesis work, a high gain, medium power, 2-18 GHz limiting amplifier module is designed, simulated, fabricated and measured. First, a 3-stage cascaded amplifier with 27 dB small signal gain is designed and fabricated. The 3-stage amplifier is composed of a novel cascaded combination of negative feedback and distributed amplifiers that provides the minimum small signal gain ripple and satisfactory input and output return losses inside 2-18 GHz frequency band. Then, the designed two 3-stage amplifiers and one 4-stage amplifier are cascaded to constitute a limiting amplifier module with minimum 80 dB small signal gain. The designed 10-stage limiting amplifier module also includes an analog voltage controllable attenuator to be used for compensating the gain variations resulting from temperature changes. The fabricated 10-stage limiting amplifier module provides 20 +/- 1.2 dBm output power level and excellent small signal gain flatness, +/- 2.2 dB, over 2-18 GHz frequency range.

APA, Harvard, Vancouver, ISO, and other styles

24

Bria, Aurelian. "Hybrid cellular-broadcasting infrastructure systems : radio resource management issues." Licentiate thesis, Stockholm, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3922.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Stevens, David Story. "TDMA slot allocation strategies for mobile packet radio networks." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/9190.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Brannon, Raymond James. "The radio spectrum requirements of broadband power line telecommunications systems." Thesis, Open University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430560.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Carvalho, Nefi Julião. "Impact of the nonlinear phenomenon on wireless radio telecommunications systems." Master's thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/1996.

Full text

Abstract:

Mestrado em Engenharia Informática
A dimensão e heterogeneidade de recentes sistemas de telecomunicações sem fios impossibilitam a previsão do comportamento do sistema completo quando operado nos limites das suas capacidades. Isto torna irrealista o estudo do impacto do fenómeno não linear no desempenho dos sistemas em especial devido a que os resultados são diferentes quando estudados em separado ou embebidos num sistema. Este trabalho ultrapassa estas problemáticas através do uso de técnicas de co-simulação e de modelação do actual estado da arte as quais tornam possível uma representação mais realista do desempenho de um sistema. ABSTRACT: The dimension and heterogeneity of recent wireless radio telecommunication systems makes impracticable the prediction of the full system behavior when pushed to its performance limits. This makes unrealistic the study of the impact of the nonlinear phenomenon on the systems performance, especially because the results are different when studied alone or embedded in a system. This work overcomes these difficulties by using state-of-the-art cosimulation and modeling techniques that made possible the presentation of more realistic system performance evaluations.

APA, Harvard, Vancouver, ISO, and other styles

28

Foster, Howard Mark Jameson. "High capacity cellular mobile radio systems." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301208.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Lee, Chin-Chun. "CDMA for cellular mobile radio systems." Thesis, University of Southampton, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240979.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Mkondweni, Ncedo Sandiso. "Design and implementation of linear robust networked control systems." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1195.

Full text

Abstract:

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology, 2013
Networked Control Systems is a control system where the plant and the controller exchange information via a shared communication network and the network is considered as part of the closed loop control system. Unfortunately the network introduces network induced random varying time delays and data packet loss amongst the communication network imperfections. The network delays are considered to be between the controller and the actuator and between the sensor and the controller. These network imperfections degrade the performance of the closed loop control system and result in closed loop system instability. The complexity of measuring the communication network imperfection in networked control systems makes it difficult for the control engineers to develop methods for design of controllers that can incorporate and compensate these imperfections in order to improve the performance of the networked control systems. In this thesis a co-simulation toolset called LabNS2 is developed to address the first problem of measuring the communication network imperfections by providing an ideal environment that can be used to investigate the influence of network time delays or packet loss. The software environment of the toolset is based on LabVIEWTM and Network Simulator Version 2 (NS2). A new robust predictive optimal controller design method is developed to address the problem of the destabilising effect of the network induced time delay between the controller and the actuator. The design approach is based on time shifting of the optimisation horizon and a state predictor. The design of the controller is based on a model of the plant with delay in the control vector equal to the delay between the controller and the actuator or to the sum of the delays between the controller and the actuator and between the sensor and the controller. The time shifting approach allows the design of the controller to be performed for a model without time delay. Then the control action is based on the future values of the state space vector estimates. The state predictor is developed to predict these future values of the state using the present and past values of the state estimates and control actions. This technique is made possible by the use of the plant model Transition Matrix. A Discrete Kalman Filter is modified to address the problem of the destabilising effect of the network induced time delay between the sensor and the controller. An additional state estimation vector is added to the filter estimate at every current moment of time. iv The developed methods are implemented for networked control of a dish antenna driven by two stepper motors. The outcomes of the thesis can be used for the education and fundamental research purposes, but the developed control strategies have significant sense towards the Square Kilometer Array projects and satellite systems industry.
National Research Foundation

APA, Harvard, Vancouver, ISO, and other styles

31

Giortzis, Athanasios. "Channel assignment in mobile radio networks." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266017.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Razavi, S. H. "Data transmission over TACS cellular radio." Thesis, University of Manchester, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329178.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Arowojolu, Adekunle Andrew. "Microcellular mobile radio measurements and modelling." Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266170.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Toh, Chai-Keong. "Protocol aspects of mobile radio networks." Thesis, University of Cambridge, 1996. https://www.repository.cam.ac.uk/handle/1810/273055.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Johansson, Leif Albin. "Broadband millimetre-wave radio over fibre systems." Thesis, University College London (University of London), 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272419.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Ho, Philip Shiu Wai. "Structural intermodulation interference in mobile radio systems." Thesis, City University London, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305174.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Tusubira, F. F. "Low level multiplexing in cellular radio systems." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.383401.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Feeney, Thomas Michael. "The complex narrowband UHF mobile radio channel." Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257146.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Ko, Yiu Fai. "Digital cellular mobile radio links and networks." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280911.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Koz, Alper. "Watermarking For 3d Representations." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608886/index.pdf.

Full text

Abstract:

In this thesis, a number of novel watermarking techniques for different 3D representations are presented. A novel watermarking method is proposed for the mono-view video, which might be interpreted as the basic implicit representation of 3D scenes. The proposed method solves the common flickering problem in the existing video watermarking schemes by means of adjusting the watermark strength with respect to temporal contrast thresholds of human visual system (HVS), which define the maximum invisible distortions in the temporal direction. The experimental results indicate that the proposed method gives better results in both objective and subjective measures, compared to some recognized methods in the literature. The watermarking techniques for the geometry and image based representations of 3D scenes, denoted as 3D watermarking, are examined and classified into three groups, as 3D-3D, 3D-2D and 2D-2D watermarking, in which the pair of symbols identifies whether the watermark is embedded-detected in a 3D model or a 2D projection of it. A detailed literature survey on 3D-3D watermarking is presented that mainly focuses on protection of the intellectual property rights of the 3D geometrical representations. This analysis points out the specific problems in 3D-3D geometry watermarking , such as the lack of a unique 3D scene representation, standardization for the coding schemes and benchmarking tools on 3D geometry watermarking. For 2D-2D watermarking category, the copyright problem for the emerging free-view televisions (FTV) is introduced. The proposed watermarking method for this original problem embeds watermarks into each view of the multi-view video by utilizing the spatial sensitivity of HVS. The hidden signal in a selected virtual view is detected by computing the normalized correlation between the selected view and a generated pattern, namely rendered watermark, which is obtained by applying the same rendering operations which has occurred on the selected view to the original watermark. An algorithm for the estimation of the virtual camera position and rotation is also developed based on the projective planar relations between image planes. The simulation results show the applicability of the method to the FTV systems. Finally, the thesis also presents a novel 3D-2D watermarking method, in which a watermark is embedded into 3-D representation of the object and detected from a 2-D projection (image) of the same model. A novel solution based on projective invariants is proposed which modifies the cross ratio of the five coplanar points on the 3D model according to the watermark bit and extracts the embedded bit from the 2D projections of the model by computing the cross-ratio. After presenting the applicability of the algorithm via simulations, the future directions for this novel problem for 3D watermarking are addressed.

APA, Harvard, Vancouver, ISO, and other styles

41

Warner, Edward Steven. "Novel bandwidth utilization techniques for radio-determination systems." Thesis, Bangor University, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316345.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Kotsopoulos, S. A. "Frequency planning techniques for cellular mobile radio systems." Thesis, University of Bradford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332176.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Hammuda, Husni. "Spectral efficiency of cellular land mobile radio systems." Thesis, University of Bristol, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279698.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Sammut, Anthony J. R. "Radio resource management for satellite personal communication networks." Thesis, University of Surrey, 1999. http://epubs.surrey.ac.uk/843349/.

Full text

Abstract:

A novel flexible channel allocation scheme is proposed which is applicable to medium altitude, high diversity satellite personal communication systems with an interconnected ground control segment. The scheme is built upon the establishment of several temporal master-slave network hierarchies in distinct areas of the Earth, whereby the control of radio resources in each area is granted to a single network entity, the master, located at one of the network's fixed earth station sites. The master station is entrusted with the radio resource management functionality equivalent to a base station controller in GSM, whereas the slaves, which consist of all FES sites which control satellites that have a current connectivity with the master's area, share the functionality of a GSM base transceiver station with the satellites under their control. The master maintains a table of all channel allocations within its control area in real-time, its objective is to maximise the number of channels which can be provided in its area, in response to channel requests by users, subject to known interference criteria. It can achieve this by optimising the existing and future channel allocations through the use of predictive satellite coverage, spotbeam gain models and genetic algorithms. Radio resource related signalling between master and slave stations is performed through a dedicated terrestrial fibre-optic network which interconnects the FES sites, based upon GSM interface specifications which are adapted to account for the increased propagation delays and signalling load associated with the regional network. The potential capacity gain which is available through a centralised optimisation approach over a fixed channel allocation scheme is determined through simulation. The instantaneous capacity of each scheme is highly dependent on the traffic distribution and the positions of the satellites, which causes an analytical approach to be too restrictive or simplistic. The capacity gain estimation is performed over a time period for which several samples are taken and a powerful adapted genetic algorithm is applied to the NP complete problem to determine the maximum capacity. The flexible dynamic system, entitled the hybrid-centralised DCA scheme, is shown to have a raw capacity potential in excess of the FCA scheme under the traffic distribution scenario adopted.

APA, Harvard, Vancouver, ISO, and other styles

45

Bensebti, M. "Wideband radio propagation measurements and modelling at 60GHz." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.319121.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Young, Michael C. S. "Application of adaptive equalisation to microwave digital radio." Thesis, University of Edinburgh, 1989. http://hdl.handle.net/1842/11654.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Kidner, David B. "Digital terrain models for radio path loss calculations." Thesis, University of South Wales, 1991. https://pure.southwales.ac.uk/en/studentthesis/digital-terrain-models-for-radio-path-loss-calculations(6733f679-d3c0-4a25-916f-0464321ea520).html.

Full text

Abstract:

This work addresses the problem of digital terrain modelling for estimating radio path propagation within a mobile communication system. The ideal requirements are for a data structure which is storage efficient and computationally efficient for calculating profiles, whilst elevation errors should be constrained and radio path loss errors should be minimised. For a digital terrain model (DTM) to be considered viable as an alternative to the regular grid, it should: (i) produce a storage saving of at least 75% over the regular grid; (ii) be error constrained to a maximum absolute error of 10 metres; (iii) produce only a small overall average elevation error; (iv) preserve critical terrain characteristics such as ridges, peaks and slopes; (v) produce 95% of profiles to within a radio path loss error of ± 6 decibels; and (vi) be as computationally efficient as the regular grid. This research focuses on the implementation of a number of prototype DTMs, including a regular grid, sub-sampled grids, variable density grids, elevation difference grids, polynomial models of fixed and variable degree, surface patch quadtrees, and triangulated irregular networks (TINs). Each of these DTMs are examined in terms of the criteria outlined above. No DTM fulfils all of these requirements. The user should identify the relative importance of each requirement before selecting a specific model. For this study, computational efficiency is identified as the criterion which can be considered the least important. With this in mind, two original DTMs are developed. These are optimised with respect to storage and error constraints. The proposed Huffman-encoded DTM represents the deviations of a regular grid of heights from linearly predicted values as variable-length codes, whilst the Implicit TIN is a storage-efficient triangulated irregular network which reconstructs the original topology of the triangulation at the application stage. Both methods produce storage savings approaching 90% over the regular grid for the data sets tested and are suitable for parallel implementations.

APA, Harvard, Vancouver, ISO, and other styles

48

AragoÌn-Zavala, Alejandro. "In-building cellular radio system design and optimisation using measurements." Thesis, University of Surrey, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273285.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Pettersen, Magne. "Three-Dimensional Radio Channel Modeling for Mobile Communications Systems." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Information Technology, Mathematics and Electrical Engineering, 2001. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-89.

Full text

Abstract:

The work described in this report is within the area of three-dimensional (3D) radio channel modeling for mobile communications. The focus was towards rural areas, because radio coverage of rural areas is more costly when using higher frequencies, comparing UMTS to GSM. In addition seasonal and environmental variations are strongest here. The model used was a 3D radar model, comprised of a 2D vertical Tx-Rx-plane component and a 3D components to include off-axis scattering. The latter components are estimated using bistatic radar techniques. The model is able to provide an accurate estimation of the path loss (signal level), and is also able to estimate time dispersion and angular dispersion, taking into account off-axis contributions. Radio frequencies around 2 GHz were selected, as these are the most important frequency bands for 3. generation mobile systems, even though the envisaged approach supports radio planning for GSM 900 and WLAN systems.

A novel approach to the modeling of scattering from random rough surfaces for 3D channel modeling was developed. This amplitude/phase model is simple and accurate compared to conventional models. It makes no inherent assumption about the degree of roughness, making it suited to model all surfaces. The model outperforms the conventional models Plane surface, SPM, Kirchoff and Oren with respect to accuracy by 1.5 to 10 dB depending on the degree of roughness.

An experimental methodology to characterise random rough surfaces was developed. The work characterised natural surfaces such as asphalt, grass, agriculture, and forest, each of them having a different degree of roughness. Variations due to weather and seasonal changes were taken into account. Typical surface height variations estimated were 10 mm for asphalt, 25 mm for grass, 100 mm for ploughed field and 500 mm for forest. Snow reduced the apparent roughness of ploughed field by 50 %, water on grass increased the reflection coefficient by 50 %.

An analysis of the implications of the results on 3D channel modeling was performed using a demonstration model. The analysis included a comparison between 2D and 3D model prediction for different area types and land use classes. Also the prediction sensitivity to seasonal and weather variations and model parameter variations were inspected. A 3D model is necessary when the 2D component is attenuated more than typically 15 dB relative to free space, depending on area and land usage. In the network planning example Lillehammer (N) this attenuation of at least 15 dB existed in 40 % of all locations. Weather and seasonal variations may change the mean predicted value by up to 4-5 dB.

APA, Harvard, Vancouver, ISO, and other styles

50

Jowett, Antony Peter. "Enhanced frequency management for automatic HF radio communication systems." Thesis, University of Hull, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292685.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Radio (telecommunication system)'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles