An abstract of the thesis of Bosi Chen for the Master of Science in Electrical and Computer Engineering presented Aug 1st, 2012. Title: Spectrum Regrowth for OFDM-based LTE and WiMAX Systems. In OFDM-based (Orthogonal Frequency Dimension Multiplexing) LTE (Long Term Evolution) and WiMAX (Worldwide Interoperability for Microwave Access) Systems, one of the critical components is the RF power amplifier. With current technologies, RF power amplifiers are not perfectly linear. The nonlinearity of an RF power amplifier is one of the main concerns in RF power amplifier design. The nonlinearity control is described by the out-of-band power emission levels, and the nonlinearity of an RF power amplifier is usually described by IP3 (the third-order intercept point). However, there is need of a clear relationship or expression between the out-of-band power emission level and IP3 for LTE and WiMAX Systems, which helps the RF designers to choose components. This thesis presents the analysis of the nonlinear effect of an RF amplifier in LTE and WiMAX Systems, and the derivation of the expressions for the estimated out-of-band emission levels for LTE and WiMAX signals in terms of IP3 and the power level of the signal. The result will be helpful for RF engineers in the design and test of RF power amplifiers in LTE and WiMAX Systems.

Network functions (NFs) hold a key role in networks, offering in-network services, such as enhanced performance, policy enforcement, and security. Traditionally, NFs have been implemented in specialized, thus expensive hardware. To lower the costs of deploying NFs, network operators have adopted network functions virtualization (NFV), by migrating NFs from hardware to software running in commodity servers. Several approaches to NFV have shown that commodity network stacks and drivers (e.g., Linux-based) struggle to keep up with increasing hardware speed. Despite this, popular networking services still rely on these commodity components. Moreover, chaining NFs (also known as service chaining) is challenging due to redundancy in the elements of the chain. This licentiate thesis addresses the performance problems of NFV service chains.The first contribution is a framework that (i) profiles NFV service chains to uncover performance degradation reasons and (ii) leverages the profiler’s data to accelerate these chains, by combining multiplexing of system calls with scheduling strategies. These accelerations improve the cache utilization and thereby the end-to-end latency of chained NFs is reduced by a factor of three. Moreover, the same chains experience a multi-fold latency variance reduction; this result improves the quality of highly-interactive services.The second contribution of this thesis substantially revises the way NFV service chains are realized. NFV service chains are synthesized while eliminating redundant input/output and repeated elements, providing consolidated stateful cross layer packet operations across the chain. This software-based synthesis achieves line-rate 40 Gbps throughput for stateful and long service chains. This performance is 8.5x higher than the performance achieved by the software-based state of the art FastClick framework. Experiments with three example Internet Service Provider-level service chains show that this synthesis approach operates at 40 Gbps, when the classification of these chains is offloaded to an OpenFlow switch. / Nätverksfunktioner (NF) har en nyckelroll i nätverk. De erbjuder tjänster i nätverken som förbättrad prestanda, policy övervakning och säkerhetsfunktioner. Vanligtvis så har NF implementerats med hjälp av specialiserad, och därmed kostsam, hårdvara. Detta har lett till att nätverksoperatörer har börjat använda nätverksfunktionsvirtualisering (NFV) för att minska kostnaden. NFV implementeras genom att NF flyttas från specialiserad hårdvara till mjukvara som kör på vanliga servrar. Flera försök med NFV har visat att vanliga nätverksstackar och drivrutiner (exempelvis Linux baserade) har svårt att erbjuda samma prestanda som hårdvaran gör. Trots detta bygger flera populära nätverkstjänster på NFV. Dessutom är det en utmaning att koppla samman NFV i kedjor, då redundanta operationer utförs. I den här avhandlingen försöker vi lösa prestanda problem kopplade till kedjor av NFV. Det första bidraget i den här avhandlingen är ett ramverk som (i) profilerar NFV kedjor för att hitta orsaker till prestanda problem samt (ii) använder profileringsdata för att förbättra prestandan i kedjorna. Detta görs genom att kombinera multiplexing av systemanrop med planläggningsstrategier. Tillsammans förbättrar dessa lösningar cache användningen och minskar därmed end-to-end latensen i kedjade NFV med en faktor tre. Dessutom minskar vår metod variansen i latens, något som är viktigt för tjänstekvalitén i interaktiva tjänster.Det andra bidraget i den här avhandlingen är en omarbetning av hur kedjade NFV konstrueras. Vi syntetiserar NFV service kedjor genom att ta bort redundanta element och konsoliderar paketoperationer som sträcker sig över flera lager i nätverksstacken. Vår mjukvarubaserade lösning klarar av 40 Gbps genomströmning i en lång kedja. Detta är 8.5 ggr mer än vad som uppnåtts med den tidigare standard lösningen för mjukvara, ramverket FastClick. Vi presenterar experiment med tre servicekedjor för nätverksleverantörer där vår syntetiserade lösning klarar 40 Gbps, när klassificeringen av kedjan görs med hjälp av en OpenFlow switch. / <p>QC 20161103</p> / European Union Horizon 2020 BEhavioural BAsed forwarding (BEBA) / European Research Council (ERC) PROPHET

Upcycling can be described as an activity where outdated or discarded products are used as raw-materials in the construction of a new object, for which an increased quality or value is achieved. Some ideas for upcycling of technologically simple products have prooved successful, in the sense that those ideas have become widespread and practically implemented within a certain target audience. This thesis explores how an idea concerning upcycling of an electric product can be developed into a prototype, with the intent to simplify application of the idea within the target audience of electronic hobbyists. This is achieved through the development of a prototype for an adapter, the purpose of which is to extend the functionality of a character based LCD module with the Hitachi HD44780 control circuit. This allows for using such LCD module for displaying text in additional languages, and (for certain applications) using it as a substitute for a monochromatic graphical LCD module. The conclusion of the study is that the adapter prototype is capable of increasing the number of user defined characters that can be displayed simeltanously by a character LCD module, and that the prototype may be of use for certain types of applications within the intended target audience. / "Upcycling" kan beskrivas som en syssla där föråldrade eller kasserade produkter används som material vid tillverkning av ett nytt föremål, vilket har högre kvalitet eller värde. Det finns exempel på idéer för "upcycling" av teknologiskt enkla produkter vilka har visat sig framgångsrika, i bemärkelsen att de har nått spridning och tillämpas praktiskt inom någon målgrupp. I detta arbete undersöks hur en idé för "upcycling" av en elektrisk produkt kan utvecklas till en prototyp, med syftet att underlätta tillämpning av denna idé inom målgruppen elektronikhobbyister. Detta sker genom utveckling av en prototyp till en adapter, som utökar funktionaliteten hos en teckendisplaymodul med styrkretsen Hitachi HD44780. Adapterns funktion är att öka det antal användardefinierade tecken som kan visas på en sådan teckendisplaymodul. Detta möjliggör att teckendisplaymodulen kan användas för att visa text på fler språk, och att den för vissa ändamål kan användas som substitut för en monokrom grafisk displaymodul. Slutsatsen av arbetet är att prototypen av denna adapter kan användas för att öka det antal användardefinierade tecken som samtidigt kan visas på en teckendisplaymodul, samt att prototypen kan vara användbar för vissa syften inom den avsedda målgruppen.

The ever increasing demands of Internet users caused by the introduction of new high bandwidth applications and online services as well as the growing number of users and devices connected to the Internet, bring many challenges for the operators, especially in the last mile section of the network. Next generation access architectures are expected to offer high sustainable bandwidth per user. They also need to support a much larger service areas to decrease number of current central offices and hence potentially save the network expenditures in the future. Obviously, it requires high capacity and low loss transmission and optical fiber technology is the only future proof candidates for broadband access. Although this technology has already been widely deployed in the core networks, it is hard to use the same expensive devices made for core segment to solve the last mile bottlenecks, due to the low number of users sharing the network resources (and deployment cost). Therefore, the next generation optical access (NGOA) networks need to be designed with consideration of cost efficiency in the first place.   Network reliability is also turning to be an important aspect for the NGOA networks as a consequence of long reach, high client count and new services requiring uninterrupted access. Consequently, new architectures not only need to be cost efficient but also they should fulfill the increasing reliability requirements.   Although several NGOA alternatives have been proposed in the literatures, there is not yet an agreement on a single architecture. As described earlier, network expenditure and reliability performance are the two main factors to be considered. Therefore, this thesis concentrates on finding a suitable alternative for future broadband access by evaluating the reliability performance and total cost of ownership for several NGOA candidates. In particular, in this thesis we analyze the tradeoff between the cost needed to deploy backup resources and the reliability performance improvement obtained by the provided survivability mechanism.   First, we identified the suitable NGOA candidates by comparing two main groups of optical access networks, namely passive optical networks (PONs) and active optical networks (AONs), in terms of cost, reliability performance and power consumption. The initial results have shown that wavelength division multiplexing PON (WDM PON) is the most promising alternative for the NGOA networks because of its high potential capacity, low cost and power consumption. So we continued our studies by investigating two WDM-based PON architectures regarding their cost and reliability performance. The study has also included a proposed fiber layout compatible with these two candidates aiming to minimize the required investment needed to offer protection. Our primary results confirmed that hybrid PON (HPON) is the best alternative for the NGOA networks. Therefore we further analyzed this candidate considering several variants of HPON. The most important components and sections of the HPON, which need to be protected to decrease the impact of each failure in the network have been identified. Based on these outcomes, two resilience architectures protecting the shared part of the HPON were proposed and their reliability performance parameters as well as cost of protection were evaluated. According to the results, using our proposed protection schemes a considerable improvement in reliability performance of the HPON variants can be provided at minor extra investment. We also introduced a cost efficient HPON architecture with different levels of protection for users with various reliability requirements, i.e. the protection of shared parts of the access network for all the connected users and end-to-end resilience scheme for some selected ones (e.g., business users). To gain an overall view on the cost efficiency of the proposed architecture, we evaluated the investment required for deploying these schemes considering several network upgrading paths towards a protected network. Moreover, a sensitivity analysis investigating the influence of network deployments time and the density of the users with higher availability requirements was presented.   In summary, we have shown that HPON is able to fulfill the main NGOA requirements such as high bandwidth per-user, large coverage and client count. The work carried out in the thesis has proved that HPON can also offer high reliability performance while keeping the network expenditures at an acceptable level. Moreover, low power consumption and high flexibility in resource allocation of this architecture, makes it a winning candidate for the NGOA networks. Therefore, HPON is a promising architecture to be deployed as NGOA network in the near future considering the fact that components are soon to be available in the market. / <p>QC 20130530</p> / FP7 EU project, Optical Access Seamless Evolution(OASE)

Emerging Ultra Wideband (UWB) Orthogonal Frequency Division Multiplexing (OFDM) systems hold the promise of delivering wireless data at high speeds, exceeding hundreds of megabits per second over typical distances of 10 meters or less. The purpose of this Thesis is to estimate the timing accuracies required with such systems in order to achieve Bit Error Rates (BER) of the order of magnitude of 10-12 and thereby avoid overloading the correction of irreducible errors due to misaligned timing errors to a small absolute number of bits in error in real-time relative to a data rate of hundreds of megabits per second. Our research approach involves managing bit error rates through identifying maximum timing synchronization errors. Thus, it became our research goal to determine the timing accuracies required to avoid operation of communication systems within the asymptotic region of BER flaring at low BERs in the resultant BER curves. We propose pushing physical layer bit error rates to below 10-12 before using forward error correction (FEC) codes. This way, the maximum reserve is maintained for the FEC hardware to correct for burst as well as recurring bit errors due to corrupt bits caused by other than timing synchronization errors.

Surface acoustic wave (SAW) sensors offer a wireless, passive sensor solution for use in numerous environments where wired sensing can be expensive and infeasible. Single carrier frequency SAW sensor embodiments such as delay lines, and resonators have been used in single sensor environments where sensor identification is not a necessity. The orthogonal frequency coded (OFC) SAW sensor tag embodiment developed at UCF uses a spread spectrum approach that allows interrogation in a multi-sensor environment and provides simultaneous sensing and sensor identi- fication. The SAW device is encoded via proper design of multiple Bragg reflectors at differing frequencies. To enable accurate device design, a model to predict reflectivity over a wide range of electrode metallization ratios and metal thicknesses has been developed and implemented in a coupling of modes (COM) model. The high coupling coefficient, reflectivity and temperature coefficient of delay (TCD) of YZ LiNbO3 makes it an ideal substrate material for a temperature sensor, and the reflectivity model has been developed and verified for this substrate. A new concept of pseudo-orthogonal frequency coded (POFC) SAW sensor tags has been investigated, and with proper design, the POFC SAW reduces device insertion loss and fractional bandwidth compared to OFC. OFC and POFC sensor devices have been fabricated at 250 MHz and 915 MHz using fundamental operation, and 500 MHz and 1.6 GHz using second harmonic operation. Measured device results are shown and compared with the COM simulations using the iii enhanced reflectivity model. Additionally, the first OFC devices at 1.05 GHz were fabricated on 128o YX LiNbO3 to explore feasibility of the material for future use in OFC sensor applications. Devices at 915 MHz have been fabricated on YZ LiNbO3 and integrated with an antenna, and have then been used in a transceiver system built by Mnemonics, Inc. to wirelessly sense temperature. The first experimental wireless POFC SAW sensor device results and predictions will be presented.

The objective of this research work is to investigate, design and measurement of a digital predistortion linearizer that is able to compensate the dynamic nonlinear distortion of a High Power Amplifier (PA). The effectiveness of the proposed baseband predistorter (PD) on the performance of a WLAN OFDM transmitter utilizing a nonlinear PA with memory effect is observed and discussed. For this purpose, a 10W Class-A/B power amplifier with a gain of 22 dB, operated over the 3.5 GHz frequency band was designed and implemented. The proposed baseband PD is independent of the operating RF frequency and can be used in multiband applications. Its operation is based on the Hammerstein system, taking into account PA memory effect compensation, and demonstrates a noticeable improvement compared to memoryless predistorters. Different types of modelling procedures and linearizers were introduced and investigated, in which accurate behavioural models of Radio Frequency (RF) PAs exhibiting linear and nonlinear memory effects were presented and considered, based on the Wiener approach employing a linear parametric estimation technique. Three new linear methods of parameter estimation were investigated, with the aim of reducing the complexity of the required filtering process in linear memory compensation. Moreover, an improved wiener model is represented to include the nonlinear memory effect in the system. The validity of the PA modelling approaches and predistortion techniques for compensation of nonlinearities of a PA were verified by several tests and measurements. The approaches presented, based on the Wiener system, have the capacity to deal with the existing trade-off between accuracy and convergence speed compared to more computationally complex behavioural modelling algorithms considering memory effects, such as those based on Volterra series and Neural Networks. In addition, nonlinear and linear crosstalks introduced by the power amplifier nonlinear behaviour and antennas mutual coupling due to the compact size of a MIMO OFDM transmitter have been investigated.

First part of this thesis presents the design, validation, and implementation of an Orthogonal Frequency Division Multiplexing (OFDM) transmitter and receiver on a Cyclone II FPGA chip using DSP builder and Quartus II high level design tools. The resources in terms of logical elements (LE) including combinational functions and logic registers allocated by the model have been investigated and addressed. The result shows that implementing the basic OFDM transceiver allocates about 14% (equivalent to 6% at transmitter and 8% at receiver) of the available LE resources on an Altera Cyclone II EP2C35F672C6 FPGA chip, largely taken up by the FFT, IFFT and soft decision encoder. Secondly, a new wavelet-based OFDM system based on FDPP-DA based channel estimation is proposed as a reliable ECG Patient Monitoring System, a Personal Wireless telemedicine application. The system performance for different wavelet mothers has been investigated. The effects of AWGN and multipath Rayleigh fading channels have also been studied in the analysis. The performances of FDPP-DA and HDPP-DA-based channel estimations are compared based on both DFT-based OFDM and wavelet-based OFDM systems. The system model was studied using MATLAB software in which the average BER was addressed for randomized data. The main error differences that reflect the quality of the received ECG signals between the reconstructed and original ECG signals are established. Finally a DA-based architecture for 1-D iDWT/DWT based on an OFDM model is implemented for an ECG-PMS wireless telemedicine application. In the portable wireless body transmitter unit at the patient site, a fully Serial-DA-based scheme for iDWT is realized to support higher hardware utilization and lower power consumption; whereas a fully Parallel-DA-based scheme for DWT is applied at the base unit of the hospital site to support a higher throughput. It should be noted that the behavioural level of HDL models of the proposed system was developed and implemented to confirm its correctness in simulation. Then, after the simulation process the design models were synthesised and implemented for the target FPGA to confirm their validation.

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