Wireless devices have become an integral part of our everyday lives. Cell-phones, PDA's, Wi-Fi enabled laptops, smart homes and appliances, and automated highway systems are some of the examples of wireless devices and networks in common use. More and more applications and functionalities are constantly being added to these devices, and to support these new applications high data rate communication is required between the wireless devices. Achieving high data rates with wireless communication is impeded by severe fluctuations in the received signal strength (called fading) due to mobility, the exponential attenuation of signal power with distance (called path loss), and interference due to simultaneous transmissions by different users at the same time or over same frequency band. Two of the promising techniques to mitigate the effects of fading, path loss, and interference are: using multiple antennas at the transmitter and receiver, and employing extra nodes (called relays) in between the transmitter and its receiver to relay the transmitter's message to its receiver. This dissertation identifies the optimal transmit and receive strategy with multiple antennas that maximizes the transmission capacity of an ad-hoc wireless network. The transmission capacity is defined as the maximum number of transmitter-receiver pairs that can simultaneously communicate under a per transmission quality of service constraint. This dissertation also presents novel relay transmission strategies for multiple antenna equipped relay based communication that achieve near optimal performance, with Shannon capacity and diversity-multiplexing tradeoff (DMT) as the performance metrics. The Shannon capacity is defined as the maximum rate of reliable communication, while the DMT characterizes the maximum diversity gain for a given value of multiplexing gain in a multiple antenna system. DMT is used as the benchmark, since transmission strategies that meet the DMT are guaranteed to leverage both the advantages of multiple antenna systems. / text

High speed serial links are critical components for addressing the growing demand for I/O bandwidth in next-generation computing applications, such as many-core systems, backplane and optical data communications. Due to continued process scaling and circuit innovations, today's CMOS serial link transceivers can achieve tens of Gb/s per pin. However, most of their reported power efficiency improves much slower than the rise of data rate. Therefore, aggregate I/O power is increasing and will exceed the power budget if the trend for more off-chip bandwidth is sustained. In this work, a system level statistical analysis of serial links is first described, and compares the link performance of Non-Return-to-Zero (2-PAM) with higher-order modulation (duobinary) signaling schemes. This method enables fast and accurate BER distribution simulation of serial link transceivers that include channel and circuit imperfections, such as finite pulse rise/fall time, duty cycle variation, and both receiver and transmitter forwarded-clock jitter. Second, in order to address link power efficiency, two test chips have been implemented. The first one describes a quad-lane, 6.4-7.2 Gb/s serial link receiver prototype using a forwarded clock architecture. A novel phase deskew scheme using injection-locked ring oscillators (ILRO) is proposed that achieves greater than one UI of phase shift for multiple clock phases, eliminating phase rotation and interpolation required in conventional architectures. Each receiver, optimized for power efficiency, consists of a low-power linear equalizer, four offset-cancelled quantizers for 1:4 demultiplexing, and an injection-locked ring oscillator coupled to a low-voltage swing, global clock distribution. Measurement results show a 6.4-7.2Gb/s data rate with BER < 10⁻¹² across 14 cm of PCB, and an 8Gb/s data rate through 4cm of PCB. Designed in a 1.2V, 90nm CMOS process, the ILRO achieves a wide tuning range from 1.6-2.6GHz. The total area of each receiver is 0.0174mm², resulting in a measured power efficiency of 0.6mW/Gb/s. Improving upon the first test chip, a second test chip for 8Gb/s forwarded clock serial link receivers exploits a low-power super-harmonic injection-locked ring oscillator for symmetric multi-phase local clock generation and deskewing. Further power reduction is achieved by designing most of the receiver circuits in the near-threshold region (0.6V supply), with the exception of only the global clock buffer, test buffers and synthesized digital test circuits at nominal 1V supply. At the architectural level, a 1:10 direct demultiplexing rate is chosen to achieve low supply operation by exploiting high-parallelism. Fabricated in 65nm CMOS technology, two receiver prototypes are integrated in this test chip, one without and the other with front-end boot-strapped S/Hs. Including the amortized power of global clock distribution, the proposed serial link receivers consume 1.3mW and 2mW respectively at 8Gb/s input data rate, achieving a power efficiency of 0.163mW/Gb/s and 0.25mW/Gb/s. Measurement results show both receivers achieve BER < 10⁻¹² across a 20-cm FR4 PCB channel. / Graduation date: 2012

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / A Communication Subsystem has been developed capable of 25 Megasymbol per Second (MSPS) data rates. The unit operates in the 8300 to 8400 MHz band and uses shaped QPSK for excellent spectral containment properties. The Communication Subsystem (CSS) has a number of features which make it attractive for many applications: (1) Data is convolutionally encoded inside the transmitter resulting in excellent link performance without using external hardware. (2) Data is encrypted inside the transmitter. The DES standard is currently implemented, however, military encryption is an option which requires minimal changes in the CSS design. (3) Frame Synchronization Sequences and Block Identification Numbers are inserted into the data by the CSS. (4) Cyclic Redundancy Checked Codes for each data block are generated within the CSS. (5) Health and Status of the CSS is formatted into digital words. (6) Mode Control, Key Maintenance, and Health and Status Reporting is easily handled through an RS-422 interface. (7) The CSS is ruggedized for launch environments and is highly reliable for space applications.

M.Ing. / The increase of interest in the development of radio communications, both terrestrial and satellite is reaching far and beyond the most optimistic expectations. There has been an accelerated emergence of newer technologies, all claiming highly coveted radio frequency spectrum resources. With the push for the development of location based services, utilizing satellite com- communications for military purposes and later for civilian use; there has been a parallel development in terrestrial communications technology making it possible to implement cost efficient reliable user systems for voice and data services ...

Este trabalho apresenta uma ferramenta para a simulação de sistemas de comunicação utilizando modelos em alto nível para cada um dos blocos empregados. A ferramenta é baseada em modelos comportamentais de blocos de Radio Freqüência (RF), o que reduz custos, tempo de simulação e permite um rápido diagnóstico de problemas precoces no projeto de um sistema de comunicação sem fio. O desenvolvimento de blocos, como o LNA (Low Noise Amplifier), o MIXER, o LO (Oscillator Local) e o PA (Power Amplifier), facilita a implementação de qualquer arquitetura de Transmissão e de Recepção. Para isso foram levados em consideração efeitos de ruído, não linearidade e ganho no modelo dos blocos. Com isto se espera que a ferramenta ajude no projeto de circuitos integrados de um sistema de blocos em cascata, onde o usuário possa selecionar, configurar e simular o sistema. Na utilização da ferramenta é indispensável um conhecimento prévio das características e especificações em nível de sistema. Assim, se poderão fazer mudanças nos parâmetros de blocos, que permitirá então analisar compromissos existentes entre ruído, ganho e distorção do sinal através de todo o caminho, antes mesmo de se ter uma resposta definitiva. A ferramenta de simulação é implementada em Simulink, que é um pacote (toolbox) de Matlab, amplamente utilizado no desenvolvimento de algoritmos e blocos de comunicação. A interação e ambiente gráfico da ferramenta facilitam o uso pelas pessoas envolvidas direta e indiretamente com o projeto de circuitos. Finalmente, para verificar a ferramenta desenvolvida foi feito um estudo de caso, onde se modelou e simulou o padrão Bluetooth. / This work presents a tool for the simulation of Communication Systems using macromodels for each block used. The tool is based on behavioral models of Radio Frequency (RF) blocks, which minimize cost, simulation time and allows a fast determination of problems in the early phases of the design of a Wireless Communication System. The development of blocks like the LNA (Low Noise Amplifier), the MIXER, the LO (Local Oscillator) and the PA (Power Amplifier), helps to implement any architecture for transmission and reception. For that, the effects of noise, non-linearity and gain in the behavioral model of the blocks were considered. With this, it is expected that the tool will help the design of integrated circuits of a system with cascade blocks, where the user can select, set up and simulate the system. In order to use the tool, previous knowledge of the characteristics and specifications of the system is necessary. In this way, it will be possible to change the parameters of blocks, allowing the analysis of tradeoffs between noise, gain and distortion of the signal through the system, before having a definite answer. The tool is implemented in Simulink, which is a toolbox of Matlab, normally used in the development of communication blocks and algorithms. The graphic environment of the tool allows a straightforward use for people involved directly or indirectly with the Circuit Design. Finally, in order to verify the developed tool, a case study was performed where the Bluetooth standard was modeled and simulated.

Hon Kwok-Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 89-91). / Abstracts in English and Chinese. / Chapter 1. --- System Architecture --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Receiver Architectures --- p.2 / Chapter 1.2.1 --- Superheterodyne Receiver --- p.2 / Chapter 1.2.2 --- Homodyne Receiver --- p.3 / Chapter 1.2.3 --- Image-Reject Receiver --- p.5 / Chapter 1.2.4 --- Low intermediate frequency Receiver --- p.7 / Chapter 1.3 --- Double Intermediate Frequency Receivers --- p.8 / Chapter 1.3.1 --- Introduction --- p.8 / Chapter 1.3.2 --- Background Theory --- p.8 / Chapter 2. --- Receiver Fundamentals --- p.23 / Chapter 2.1 --- Noise model --- p.23 / Chapter 2.1.1 --- Thermal noise of resistors --- p.23 / Chapter 2.1.2 --- Channel noise of transistors --- p.24 / Chapter 2.2 --- Noise Figure --- p.26 / Chapter 2.3 --- Linearity --- p.26 / Chapter 2.3.1 --- 1 -dB Compression point --- p.27 / Chapter 2.3.2 --- Third Intercept point (IP3) --- p.28 / Chapter 2.3.3 --- Dynamic Range (DR) --- p.30 / Chapter 2.3.3.1 --- Spurious-Free Dynamic Range (SFDR) --- p.30 / Chapter 2.3.3.2 --- Blocking Dynamic Range (BDR) --- p.32 / Chapter 3. --- Spiral Inductor --- p.33 / Chapter 3.1 --- Spiral inductor modeling --- p.34 / Chapter 3.2 --- Spiral Inductor model parameters --- p.36 / Chapter 3.3 --- Characteristic of spiral inductor --- p.36 / Chapter 3.4 --- Inductor Design and Optimization --- p.37 / Chapter 4. --- Low Noise Amplifier (LNA) --- p.39 / Chapter 4.1 --- Introduction --- p.39 / Chapter 4.2 --- Common LNA Architectures --- p.39 / Chapter 4.2.1 --- Resistive Termination --- p.39 / Chapter 4.2.2 --- 1/gm Termination --- p.42 / Chapter 4.2.3 --- Shunt-Series Feedback --- p.43 / Chapter 4.2.4 --- Inductive Source Degeneration --- p.43 / Chapter 4.3 --- Full Schematic diagram of the Low Noise Amplifier --- p.45 / Chapter 4.4 --- Full noise analysis of the LNA using inductive source degeneration --- p.46 / Chapter 4.4.1 --- Output noise due to channel noise --- p.46 / Chapter 4.4.1.1 --- Output noise due to i2d --- p.47 / Chapter 4.4.1.2 --- "Output noise due to i2g,u" --- p.47 / Chapter 4.4.1.3 --- "Output noise due to i2g,c and i2d" --- p.49 / Chapter 4.4.2 --- "Output noise due to Rg R,l Rs" --- p.51 / Chapter 4.4.3 --- Noise factor calculation --- p.52 / Chapter 4.4.3.1 --- Rl calculation --- p.52 / Chapter 4.4.3.2 --- Rg calculation --- p.52 / Chapter 4.4.3.3 --- Ql calculation --- p.53 / Chapter 4.4.3.4 --- wT calculation --- p.53 / Chapter 4.4.3.5 --- x calculation --- p.53 / Chapter 4.5 --- Simulation Result of the low noise amplifier (100 finger gate poly) --- p.54 / Chapter 4.5 --- Experimental Result of the low noise amplifier (100 finger gate poly) --- p.56 / Chapter 5. --- Down-conversion Mixer --- p.58 / Chapter 5.1 --- Introduction --- p.58 / Chapter 5.2 --- Gilbert Cell Mixer --- p.59 / Chapter 5.2.1 --- Circuit Description --- p.59 / Chapter 5.2.2 --- Basic Operation --- p.60 / Chapter 5.2.3 --- Simulation Result of the Gilbert Cell Mixer --- p.62 / Chapter 5.3 --- Single-ended to Differential-ended Converter --- p.66 / Chapter 5.3.1 --- Simulation Result of the Single-Ended to Differential-Ended Converter --- p.68 / Chapter 5.4 --- Experimental Result of The Gilbert Cell Mixer --- p.70 / Chapter 5.4.1 --- 1-dB compression point experiment --- p.70 / Chapter 5.4.2 --- IIP3 experimental setup and result --- p.72 / Chapter 5.4.3 --- "Experimental result of 1 -dB compression point, IIP3, conversion gain, SFDR and BDR" --- p.74 / Chapter 5.4.4 --- LO power verse conversion gain --- p.75 / Chapter 5.4.5 --- Intermediate frequency verse conversion gain --- p.77 / Chapter 5.4.6 --- Experimental result of input matching and isolation --- p.78 / Chapter 6. --- Asymmetric Polyphase Network --- p.81 / Chapter 6.1 --- Introduction --- p.81 / Chapter 6.2 --- Performance of the Asymmetric Polyphase Network --- p.81 / Chapter 6.2.1 --- First Building Block --- p.82 / Chapter 6.2.2 --- Second Building Block --- p.83 / Chapter 6.2.3 --- Third Building Block --- p.84 / Chapter 6.2.4 --- Forth Building Block --- p.84 / Chapter 6.3 --- Simulation result of the asymmetric polyphase network --- p.85 / Chapter 6.4 --- Experimental result of the asymmetric polyphase network --- p.86 / Chapter 7. --- Conclusion --- p.87 / Chapter 8. --- Reference --- p.89 / Chapter 9. --- Appendix A --- p.92 / Chapter 10. --- Appendix B --- p.95 / Chapter 11. --- Appendix C --- p.98 / Chapter 12. --- Appendix D --- p.99

Este trabalho apresenta uma ferramenta para a simulação de sistemas de comunicação utilizando modelos em alto nível para cada um dos blocos empregados. A ferramenta é baseada em modelos comportamentais de blocos de Radio Freqüência (RF), o que reduz custos, tempo de simulação e permite um rápido diagnóstico de problemas precoces no projeto de um sistema de comunicação sem fio. O desenvolvimento de blocos, como o LNA (Low Noise Amplifier), o MIXER, o LO (Oscillator Local) e o PA (Power Amplifier), facilita a implementação de qualquer arquitetura de Transmissão e de Recepção. Para isso foram levados em consideração efeitos de ruído, não linearidade e ganho no modelo dos blocos. Com isto se espera que a ferramenta ajude no projeto de circuitos integrados de um sistema de blocos em cascata, onde o usuário possa selecionar, configurar e simular o sistema. Na utilização da ferramenta é indispensável um conhecimento prévio das características e especificações em nível de sistema. Assim, se poderão fazer mudanças nos parâmetros de blocos, que permitirá então analisar compromissos existentes entre ruído, ganho e distorção do sinal através de todo o caminho, antes mesmo de se ter uma resposta definitiva. A ferramenta de simulação é implementada em Simulink, que é um pacote (toolbox) de Matlab, amplamente utilizado no desenvolvimento de algoritmos e blocos de comunicação. A interação e ambiente gráfico da ferramenta facilitam o uso pelas pessoas envolvidas direta e indiretamente com o projeto de circuitos. Finalmente, para verificar a ferramenta desenvolvida foi feito um estudo de caso, onde se modelou e simulou o padrão Bluetooth. / This work presents a tool for the simulation of Communication Systems using macromodels for each block used. The tool is based on behavioral models of Radio Frequency (RF) blocks, which minimize cost, simulation time and allows a fast determination of problems in the early phases of the design of a Wireless Communication System. The development of blocks like the LNA (Low Noise Amplifier), the MIXER, the LO (Local Oscillator) and the PA (Power Amplifier), helps to implement any architecture for transmission and reception. For that, the effects of noise, non-linearity and gain in the behavioral model of the blocks were considered. With this, it is expected that the tool will help the design of integrated circuits of a system with cascade blocks, where the user can select, set up and simulate the system. In order to use the tool, previous knowledge of the characteristics and specifications of the system is necessary. In this way, it will be possible to change the parameters of blocks, allowing the analysis of tradeoffs between noise, gain and distortion of the signal through the system, before having a definite answer. The tool is implemented in Simulink, which is a toolbox of Matlab, normally used in the development of communication blocks and algorithms. The graphic environment of the tool allows a straightforward use for people involved directly or indirectly with the Circuit Design. Finally, in order to verify the developed tool, a case study was performed where the Bluetooth standard was modeled and simulated.

Idag väljer allt fler butiker att starta en webbshop och på så vis nå ut till fler kunder samt marknadsföra sig på ett enkelt vis. Eftersom konsumenter söker och jämför produkter via Internet är det viktigt att företag och deras erbjudande är tillgängliga även där och inte försvinner i det brus som uppstår på marknaden på grund av exempelvis konkurrenter. Syftet med vårt arbete är att undersöka, analysera samt diskutera hur en mindre klädbutik påverkas av att både driva en butik och en webbshop samt även vilka fördelar som kan utnyttjas. Vi har intervjuat tre företag som har fått svara på ett antal frågor om hur det är att driva en webbshop. Vi valde att intervjua mindre butiker som använder sig av webbshop som ett komplement, för att se hur det påverkar företaget. Dessutom har vi skickat ut en webbenkät där konsumenterna fått besvara ett antal frågor om deras shoppingvanor på Internet. Det var relevant för oss att undersöka både företagens och konsumenternas syn på näthandel, för att få en så rättvis bild som möjligt av hur det ser ut i verkligheten. Utifrån våra undersökningar tillsammans med vår teoretiska referensram har vi kommit fram till att en hemsida med webbshop är ett bra sätt att marknadsföra sig på och nå ut till potentiella kunder. Det visade sig också att kunder flera gånger i veckan besöker en webbshop och handlar någon eller några gånger i månaden. Från företagens perspektiv har vi fått reda på att det är en kostsam process att driva näthandel. Det kräver mycket tid och energi för ständigt hålla sidan uppdaterad. Today, more and more stores choose to start an online shop and thus reach more customers and market themselves in a simple way. As consumers search and compare products thru the Internet, it is important that companies and their offer is also available there and not lost in the noise that occurs in the market because of such competitors. The aim of our work is to investigate, analyze, and discuss how a small clothing shop is influenced by both operate a retail store and an online store as well as the benefits that can be utilized. We interviewed three companies that have been asked a number of questions about how it is to run a shop. We chose to interview smaller shops that use web shop as a supplement, to see how it affects the company. In addition, we sent out an online survey in which consumers had to answer a number of questions about their shopping habits on the Internet. It was appropriate for us to examine both the business and consumer views on e-commerce, to get as fair a picture as possible of how it looks in reality. Based on our studies, together with our theoretical framework, we have concluded that a website with online shop is a great way to market themselves and reach out to potential customers. It was also found that customers several times a week visiting a web shop and is one or a few times a month. From the corporate perspective, we have learned that it is a costly process to drive online sales. It requires a lot of time and energy to constantly keep the site updated. / Program: Butikschefsutbildningen

<p>Three of the most important factors with regards to wireless multi-hop networks, namely reachability, energy consumption and network stability are considered in our transmitter macrodiversity supported broadcasting routing algorithms. Broadcasting applications are not only used to send routing table, queries, programming logic, any specific request etc. to all the nodes from access point but are also capable of playing a vital role in wireless TV distributions and visual sensor networks. All the algorithms are simulated in the MATLAB environment in which the nodes are random and are battery driven on a multi-hop randomized topology. Four new single frequency network (SFN) based algorithms (SFN-A, SFN-B, SFN-C and SFN-D) are formed in order to work over multi-hopping and where three of the algorithms SFN-A, SFN-B and SFN-D bear more or less the same amount of reachability. These three algorithms are able to reach more than 90% of reachability in only Tx power -8dBm whereas non-SFN requires -4dBm and SFN-C requires -2dBm and, in addition can achieve a maximum of 29 percentage points more reachability than the non-SFN algorithm. However, the best algorithm SFN-D consumes a maximum of 58.76% less energy than the SFN-A and a maximum of 14.28% less energy than the SFN-B. The SFN-D algorithm achieves a maximum 3.43 dB diversity gain together with the maximum 37.33% energy consumption gain in comparison to the non-SFN algorithm.</p>

<p>The goal of this final year project is to investigate various techniques to up-convert a baseband signal into radio frequency signals, and to investigate the practical problems encountered in an offset phase locked loop design by implementation. </p><p>Phase locked loops are commonly used in radio transmitters and receivers to generate accurate RF signals from a low-frequency reference. This thesis will highlight some of the problems and strengths of various up-conversion schemes, and suggest an offset-PLL architecture free from many of those problems. </p><p>An offset-PLL is often used in mobile communication systems where the required levels of out of band transmission are tough and the use of superheterodyne up-conversion cannot be used due to spectrum or bandwidth requirements. </p><p>However a drawback of an offset-PLL is the high locking time; this can render the offset-PLL useless in TDMA communication systems. This problem among others has been studied theoretically as well as practically on an actual implementation of an offset-PLL for mobile communications. The offset-PLL was designed and manufactured as part of this project.</p>