In the past, the design of PC algorithms for CDMA systems has remained at the physical layer to compensate for slow and fast channel impairments (known as fast PC and slow PC). The TDMA/FDMA manages inter-cell interference at the beginning of the radio planning process. In SS technology, real time adaptive PC and power management algorithms would need to work coherently to ensure reliable multi-media services, and the need for this real-time hybrid structure of PC and power management has only been shown recently. The emphasis in this dissertation is therefore on the design of a QoS-based PC structure in W-CDMA applications, the ultimate goal being to evaluate the new QoS-based PC structure by means of a Monte Carlo computer simulation; a multi-user, multimedia W-CDMA simulation package. Before the design of the QoS-based PC structure, this dissertation examines and proposes a new power-sensitive model that addresses factors affecting the W-CDMA system capacity. Consequently, PC problems are put into a framework for various optimization criteria. Finally the design of a QoS-based PC structure by means of Monte Carlo computer simulation is described and evaluate. The first problem is closely related to the fact that W-CDMA is a design of a power management network architecture. The power management can co-exist in every layer of operation with different specific time scale and optimization objectives. The solution to this problem is therefore to introduce a general and mathematically tractable power-sensitive model to identify factors that influence the capacity of W-CDMA cellular systems and then articulate the general power sensitive model to form a PC framework aimed at finding a common systematic treatment for different schools of thought on PC algorithms. This dissertation proves the benefits of layered PC operation for guaranteed QoS transmission and also shows that this research coincides with and extend the literature on PC management by categorizing PC algorithms according to various optimization objectives and time scales. The second problem is to evaluate the new QoS-based PC structure in a channel coded and RAKE combining uplink UMTSIUTRA cellular environment using the Monte Carlo simulation package. The UMTS radio channel models are described in terms of frequency-selective Rayleigh fading: Indoor-Office, Outdoor and Pedestrian and Vehicular environments. The package is simulated in Matlab. The influence of the number of multipath components, of Doppler Spread, the number of received antenna, the coding scheme and multi-access interference are discussed in the dissertation. The performance evaluation criteria for utility-based PC structures are Bit-Error-Rate (BER) performance (robustness), outage performance (tracking ability) and rate of convergence. The first test shows that the new proposed unbalanced step-size closed-loop FPC schemes can provide better SINR tracking ability and better BER performance than conventional balanced step-size PC schemes. The unbalanced FPCs have better PC error distribution in all scenarios. The second test shows that the proposed BER-prediction distributed OPC schemes can provide better BER tracking ability. This scheme converges iteratively to an optimal SINR level under current network settings with no excessive interference to other active users. / Dissertation (M Eng (Electronics))--University of Pretoria, 2006. / Electrical, Electronic and Computer Engineering / Unrestricted

Zhao Fei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 87-89). / Abstracts in English and Chinese. / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Multirate Scheme --- p.2 / Chapter 1.1.1 --- VSF Scheme --- p.3 / Chapter 1.1.2 --- Multicode Scheme --- p.5 / Chapter 1.2 --- Multicode CDMA System --- p.7 / Chapter 1.2.1 --- System Model --- p.7 / Chapter 1.2.2 --- Envelope Variation of Multicode Signal --- p.9 / Chapter 1.2.3 --- Drawback of Multicode Scheme --- p.11 / Chapter 1.3 --- Organization of the Thesis --- p.13 / Chapter 2. --- Related Work on Minimization of PAP of Multicode CDMA --- p.15 / Chapter 2.1 --- Constant Amplitude Coding --- p.16 / Chapter 2.2 --- Multidimensional Multicode Scheme --- p.22 / Chapter 2.3 --- Precoding for Multicode Scheme --- p.25 / Chapter 2.4 --- Summary --- p.26 / Chapter 3. --- Multicode CDMA System with Constant Amplitude Transmission --- p.27 / Chapter 3.1 --- System Model --- p.28 / Chapter 3.2 --- Selection of Hadamard Code Sequences --- p.31 / Chapter 3.3 --- The Optimal Receiver for the Multicode System --- p.37 / Chapter 3.3.1 --- The Maximum-Likelihood Sequence Detector --- p.38 / Chapter 3.3.2 --- Maximum A Posteriori Probability Detector --- p.41 / Chapter 4. --- Multicode CDMA System Combined with Error-Correcting Codes --- p.45 / Chapter 4.1 --- Hamming Codes --- p.46 / Chapter 4.2 --- Gallager's Codes --- p.48 / Chapter 4.2.1 --- Encoding of Gallager's Codes --- p.48 / Chapter 4.2.2 --- Multicode Scheme combined with Gallager's Code --- p.52 / Chapter 4.2.3 --- Iterative Decoding of the Multicode Scheme --- p.55 / Chapter 4.3 --- Zigzag Codes --- p.59 / Chapter 4.4 --- Simulation Results and Discussion --- p.62 / Chapter 5. --- Multicode CDMA System with Bounded PAP Transmission --- p.68 / Chapter 5.1 --- Quantized Multicode Scheme --- p.69 / Chapter 5.1.1 --- System Model --- p.69 / Chapter 5.1.2 --- Interference of Code Channels --- p.71 / Chapter 5.2 --- Parallel Multicode Scheme --- p.74 / Chapter 5.2.1 --- System Model --- p.74 / Chapter 5.2.2 --- Selection of Hadamard Code Sequences --- p.75 / Chapter 6. --- Conclusions and Future Work --- p.82 / Chapter 6.1 --- Conclusions --- p.82 / Chapter 6.2 --- Future Work --- p.84 / Bibliography --- p.87

Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2008. / Laskar, Joy, Committee Chair ; Cressler, John, Committee Member ; Kornegay, Kevin, Committee Member ; Tentzeris, Emmanouil, Committee Member ; Lee, Chang-Ho, Committee Member.

Mobile commerce, due to its inherent characteristics of mobility and reachability in enhancing personalized services provides an excellent means for life insurers to exploit such avenue in their service offerings. The objective of this study was to determine whether mobile commerce can be used to improve the services of life insurance post-sale activities. This objective was achieved with the relevant literature and empirical study. To accomplish the objective of this treatise, a triangulated research approach was selected and a multiple-case study consisting of four cases was conducted. The four cases selected comprised of leading insurers with large market share in the life insurance market in South-Africa. The primary data were collected through questionnaire and face-to-face interviews with selected respondents. The main finding shows that the respondents had a positive view about mobile commerce and its application in their companies. This was demonstrated by 80 percent of respondents who agreed that mobile commerce was more of an opportunity rather than a challenge or even a threat for the life insurance market. The results also indicate that customer relationship management, mobile messaging services and field service automation functions were used by all the insurers; although minor discrepancies were observed due to the efficiency of each firms IT infrastructure. The Internet was found to assist in the collection of more precise data, to increase service performing abilities. Some of the major obstacles that were found to hinder the deployment of mobile commerce in the industry were security concerns, low and infrequent internet usage and performance by supporting industries. Cumbersome and inefficient legacy systems were declared as the greatest technological weakness particularly by respondents from case 1 and 2. Conversely, hardware and network infrastructure, lack of software packages, lack of technical expertise and the fear of disintermediation was rated low in hindering the deployment of mobile commerce. However, according to the findings the key benefits derived from engaging in increased mobile commerce activities include enhancing customer contact and service, more transparency and speed of claims management, increasing client retention and policy extension rates hence increasing overall company profit.

Satellites typically communicate with locations on the ground to receive commands and send data back. Establishing reliable communications generally requires dedicated ground stations, which in turn require hardware and expertise. Developers of nano-satellites, however, may not have the expertise or resources necessary for establishing a dedicated ground station. Therefore, the use of an existing communication system, such as the Satellite Personal Communication Networks (S-PCNs), is attractive. Another shortcoming of the fixed ground stations, already available, is that they are normally only able to communicate with Low Earth Orbit (LEO) nano-satellites four times per day (two10-minute windows separated by 90 minutes, followed 12 hours later by two more such 10-minute windows). This drawback is also overcome by the use of S-PCNs which provide increased access times, smaller gaps in contact between the satellites and ground stations, and easier tracking of satellite health. In this thesis, the capabilities of S-PCNs for communications with a nano-satellite are explored. Software simulation and analysis have been performed to assess system performance. Ground testing of the hardware is done to understand the use of such systems for small satellites.

published_or_final_version / Business Administration / Master / Master of Business Administration

Kwok Pui-ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves [79]-85). / Abstracts in English and Chinese. / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter CHAPTER 2 --- NONLINEAR BEHAVIOR OF RF POWER AMPLIFIERS --- p.5 / Chapter 2.1 --- Single Tone Excitation --- p.6 / Chapter 2.1.1 --- AM-AM Conversion --- p.7 / Chapter 2.1.2 --- AM-PM Conversion --- p.9 / Chapter 2.2 --- Two-Tone Excitation --- p.11 / Chapter 2.2.1 --- Intermodulation Distortion --- p.12 / Chapter 2.3 --- Digitally Modulated Signal Excitation --- p.13 / Chapter 2.3.1 --- Spectral Regeneration --- p.14 / Chapter 2.3.2 --- Adjacent Channel Power Ratio (ACPR) --- p.16 / Chapter CHAPTER 3 --- LINEARIZATION TECHNIQUES --- p.18 / Chapter 3.1 --- pre-distortion --- p.20 / Chapter 3.2 --- Feed-forward Techniques --- p.23 / Chapter 3.3 --- Harmonics Control Techniques --- p.24 / Chapter CHAPTER 4 --- SPECTRAL REGROWTH ANALYSIS USING VOLTERRA SERIES METHOD --- p.26 / Chapter 4.1 --- Introduction To Volterra Series Analysis --- p.27 / Chapter 4.1.1 --- Linear and Nonlinear Systems --- p.27 / Chapter 4.1.2 --- Evaluation of Volterra transfer function --- p.29 / Chapter 4.1.3 --- Volterra Series Analysis of Spectral Regrowth --- p.31 / Chapter 4.2 --- Nonlinear Model of GaAs MESFET Device --- p.33 / Chapter 4.3 --- Evaluation Of Nonlinear Responses --- p.35 / Chapter 4.3.1 --- First-Order Response --- p.36 / Chapter 4.3.2 --- Second-Order Response --- p.38 / Chapter 4.3.3 --- Third-Order Response --- p.39 / Chapter CHAPTER 5 --- EFFECT OF HARMONIC TUNING ON SPECTRAL REGROWTH --- p.42 / Chapter 5.1 --- Simulation of Digitally Modulated Signal --- p.43 / Chapter 5.2 --- Effect of Source Second Harmonic Termination --- p.44 / Chapter CHAPTER 6 --- EXPERIMENTAL VERIFICATION --- p.48 / Chapter 6.1 --- Circuit Design and Construction --- p.49 / Chapter 6.2 --- Setup and Measurement --- p.55 / Chapter 6.3 --- Experimental Results --- p.56 / Chapter 6.3.1 --- Small Signal Measurement --- p.56 / Chapter 6.3.2 --- Single Tone Characterization --- p.57 / Chapter 6.3.3 --- Two-Tone Characterization --- p.59 / Chapter 6.3.4 --- ACPR Characterization --- p.60 / Chapter 6.4 --- Comparison of Measurement and Simulation --- p.66 / Chapter CHAPTER 7 --- NONLINEAR TRANSCONDUCTANCE COEFFICIENTS EXTRACTION --- p.68 / Chapter 7.1 --- Large Signal Model --- p.69 / Chapter 7.2 --- Extraction of Nonlinear Transconductance --- p.71 / Chapter 7.2.1 --- Extraction of g1 --- p.71 / Chapter 7.2.2 --- Extraction of g2 and g3 --- p.72 / Chapter CHAPTER 8 --- CONCLUSION --- p.76 / FUTURE WORK RECOMMENDATION --- p.78 / REFERENCE

The area of deterministic noise cancellation in mobile radio communication systems is investigated and analyzed. Several interoperation problems in the mobile wireless radio space are identified and interference concerns for the Bluetooth - WLAN networks are characterized and quantified in the physical layer. A mathematical framework has been created for describing interference in the 2.4 GHz band. An adaptive noise suppression system has been developed that is able to alleviate the encroachment of the aggressor signal on the victim without sacrificing any of the original signal. This system is demonstrated to improve the victim SNR in a spread spectrum communication scenario. The research is extended to construct an interference canceller that is easy to assimilate into existing RF front-ends. A low-power small form-factor analog active canceller has been designed in 0.18-ìm Si-CMOS IC technology that delivers adequate noise suppression performance while operating in the RF domain. This includes novel implementations of phase rotator circuits based on delay interpolation and an integrated low-current quadrature modulator-based continuously variable analog phase shifter. This canceller is capable of up to 30 dB of in-band cancellation for the Bluetooth - WLAN problem. Other versions of the canceller are configured to protect GPS and DVB-H receivers from unintentional radiators transmitting in the vicinity. These demonstrate noise mitigation of at least 15 dB in their respective bands while generating very low broadband noise at the output. A simple low-power mixed-signal automatic control mechanism is also developed to operate the canceller adaptively. The work described in this dissertation advances the state-of-the-art in the area of mobile wireless radio coexistence.

Digitaliseringen tar en allt större roll i det svenska samhället, vilket leder till att företag måste anpassa sig efter förändringarna som digitaliseringen innebär. Anpassningen görs eftersom att revisionsbranschen är en institution som strävar efter högt socialt kapital. Syftet med examensarbetet är att förklara hur digitaliseringen påverkar kundrelationen mellan revisorn och kunden inom revisionsbranschen, utifrån revisorns perspektiv. För att uppnå syftet tar uppsatsen sin utgångspunkt i det positivistiska synsättet och i en teoretisk referensram som ligger till grund för en utvecklad analysmodell. Den teoretiska referensramen visar på betydelsen av socialt kapital för att bygga upp meningsfulla värden och utveckla långsiktiga relationer. Empirin har samlats in genom en såväl kvantitativ som kvalitativ metod där revisorers åsikter kring hur digitaliseringen påverkar relationen i branschen ligger till grund för examensarbetets slutsatser. Resultatet från empirin har kodats och analyserats i flera analysmodeller. Bland annat ett hypotestest som visade på att tre av uppsatsens fyra hypoteser kunde verifieras. Examensarbetets diskussion och slutsats visar på flertalet intressanta resultat. Ett utmärkande resultat är att revisionsbranschen är en institution där arbetssättet utvecklats från att vara formellt till informellt. Anledningen till detta är att det finns en stark norm inom professionen som underbyggs av ett sådant arbetssätt som är djupt rotad i digitalisering. Examensarbetets resultat redogör även för att fysiska möten inte är lika självklara idag som tidigare. Dock går de inte att utesluta helt då de krävs för att bygga och underhålla en långsiktig relation. Resultatet visar även att det är viktigt att bemöta kunders förväntningar och reducera osäkerhet. En skillnad mellan kvinnor och män i valet av att gå på informella sammankomster med en kund har även uppmärksammats. Examensarbetet visar på ytterligare en skillnad, som är mellan yngre och äldre där yngre är mer positiv till digital kommunikation framför personlig kommunikation. Avslutningsvis bekräftar examensarbetet att digitaliseringen påverkar relationen mellan revisorn och kunden och att digitala relationer som utvecklas inom branschen är en institution. / Digitalization takes an increasing role in the Swedish society, which means that companies must adapt to the changes that digitalization leads to. The adjustments are made on the basis that the audit industry is an institution that strives for high social capital. The purpose of this study is to explain how digitalization affects the relationship between the auditor and the customer in the audit industry, based on the auditor's perspective. To achieve the study’s objective, it is based on a positivist approach and the theoretical framework is the foundation for the analytical model. It defined the importance of social capital to build meaningful values and develop long-term relationships. The data collection is based on both quantitative and qualitative methods, where the core is to investigate how digitization affects the relationship in the industry. The collected data has been coded and analyzed in several analysis models. For example, one test of hypothesis which showed that three of the study’s four hypotheses could be verified. The discussion and conclusion of the study showed multiple interesting results, where a distinguish result was that the audit profession in an institution and the working process has changed from being formal to be informal. The reason is that the norm within the profession is deeply rooted in digitalization. The study also concluded that meetings face-to-face are not as self-evident today as it was before the development of digitalization. However, face-to-face meetings cannot be eliminated as they are seen as necessary to develop a long and sustainable relationship and whereas digital tools of communications are seen as a complement. The results also suggests the importance to meet customer expectations and reducing uncertainty. The thesis also found a difference between women and men in the choice of attending to informal meetings. It was also recognized that younger has an increasing interest in digital communications, compare to older auditors. Finally the study confirms that digitalization affects the relationship between the auditor and the customer, and that digital relationships developed in the auditing industry are an institution.

[pt] À medida que os sistemas de comunicações móveis e de rádiodeterminação que utilizam satélites não geo-estacionários de órbitas baixas e médias ganham importância no cenário mundial de comunicações, torna-se cada vez mais necessário o conhecimento do ambiente de rádio- propagação, seu comportamento e a inter-relação entre os seus diversos aspectos e parâmetros. Em função de características dos dispositivos de comunicações utilizados em tais sistemas, como transmissores de baixa potência e antenas de baixo ou médio ganho, esses sistemas operam com margens de desvanecimento relativamente baixas. A literatura descreve uma técnica de simulação para estimação de margens de desvanecimento em diversos tipos de ambiente baseada em fotografias obtidas com a utilização de câmaras providas de lentes grande-angulares. Na presente dissertação, apresenta-se uma variante da metodologia original, onde se propõe a substituição da base de dados original por mapas digitais da topografia, combinada com bases de dados de edificações e de um modelo para a vegetação. Apresenta-se, ainda, a estrutura da simulação computacional utilizada para processar e analisar tais arquivos, os dados de entrada da simulação e um módulo que representa a dinâmica orbital, utilizado para prever as posições dos satélites. Finalmente, apresentam-se e analisam-se os resultados obtidos com a presente simulação. Analisa-se, também, a influência da variação dos diversos fatores que compõem os dados de entrada da simulação nos resultados obtidos. / [en] As land-mobile satellite systems and radio-determination systems get more importance in the global telecommunications scenario, it becomes even more necessary to understand the radio-propagation environment: its behavior and the inter-relationship between its several aspects and physical parameters. Due to the communications devices characteristics used in these systems, such as low-power transmitters and low/medium gain antennas, such systems operate with relatively low fade margins. The technical literature describes a simulation technique to estimate fade margins in various types of environments, based on the processing of photographs acquired by digital cameras utilizing fisheye lenses. In this dissertation, an alternate methodology is presented. It is proposed that the original database of photographs be substituted by digital elevation models combined with building databases and a vegetation model. The computer simulation structure used to process and analyzes these databases, the input simulation data, and an orbital dynamics model used to update the satellite positions are also described. Finally, the obtained simulation results are presented and analyzed. It also discusses the influence of several factors which characterize different urban regions and non geostationary orbit satellite networks in the obtained results.