<p>The use of relays is seen as a promising way to extend cell coverage and increase rates in LTE Advanced networks. Instead of increasing the number of base stations (BS), relays with lower cost could provide similar gains. A relay will have a wireless link to the closest BS as only connection to the core network and will cover areas close to the cell edge or other areas with limited rates.</p><p>Performing transmissions in several hops (BS-relay & relay-user) requires more radio resources than using direct transmission. This thesis studies how the available radio resources should be allocated between relays and users in order to maximize throughput and/or fairness. Time and frequency multiplexed backhaul is investigated under a full buffer traffic assumption. It is shown that the system will be backhaul limited and that the two ways of multiplexing will perform equally when maximising throughput and/or fairness. The analysis results in a set of throughput/fairness suboptimal solutions, dependant on how many relays are used per cell. The results are verified by simulations, which also show the limiting effects on throughput caused by interference between relays.</p><p>It is also analysed how the resource allocation should be done given non-fullbuffer traffic. A resource allocation that minimises packet delay given a certain number of relays per cell is presented. The analysis is based on queuing theory.</p><p>Finally some different schedulers and their suitability for relay networks are discussed. Simulation results are shown, comparing the throughput and fairness of Round Robin, Weighted Round Robin, Proportional Fairness and Weighted Proportional Fairness schemes. It is shown that allocating the resource among the relays according to the number of users served by the relays improves the fairness.</p>

<p>Due to rapid growth of home entertainment consumer market, video technology has been continuously pushed to deliver sharper pictures with higher resolution. This has brought about stringent requirements on the video analog front end, which often coupled with the low power and low voltage regulations had to deal with short channel effects of the deep submicron CMOS processes.</p><p>This thesis presents the design of a fully differential programmable gain amplifier, as a subcircuit of a larger video digitizing IC designed at division of Electronic Systems. The switched capacitor architecture of the PGA does not only buffer the signal, but performs compensation for the sync-tip of analog video signal.</p><p>The pseudo differential OTA eliminates tail current source and maintains high signal swing and has efficient common mode feedforward mechanism. When coupled with a similar stage provides inherent common moode feedback without using an additional SC-CMFB block.</p><p>The PGA has been implemented using a 65 nm digital CMOS process. Expected difficulties in a 1.2 V OTA design make themselves evident in 65 nm, which is why cascaded OTA structures were inevitable for attaining gain specification of 60 dB. Nested Miller compensation with a pole shifting source follower, stabilizes the multipole system. The final circuit attains up to 200 MHz bandwidth and maintains high output swing of 0.85 V. High slew rate and good common mode and power supply rejection are observed. Noise requirements require careful design of input differential stage. Although output source follower stabilized the system, it reduces significant bandwidth and adds to second order non-linearity.</p>

<p>In this bachelor thesis a complete prototype of an industrial vibration measurement platform has been developed. By measuring a number of variables such as acceleration, temperature and speed conclusions can be drawn on machinery health. The aim is to evaluate hardware and software solutions for a possible future product. Based on a requirement specification a proper hardware design has be developed. The hardware consists of a four-layer PCB with an ARM Cortex-M3 microcontroller and about 250 other components. The PCB was designed, assembled, tested and finally housed in a box. Measures have been taken to protect the prototype against external disturbances such as inappropriate supply voltages and transients on the input stages.Software has been written for the microcontroller to perform the various measurements required by the prototype. These include RMS, integration and filtering. Special attention was paid to the latter by implementing filters based on lattice wave digital structures. This structure results in a very efficient implementation. Consideration is taken to be able to generate arbitrary filters independent of the characteristics and design method. To save time the microcontroller implements all the algorithms without any floating point numbers.Furthermore, both hardware and software are adapted for future industrial use. The finished prototype supports a number of communication interfaces in which Modbus (RS-485) and current loop communication can be mentioned.The final result is a very good performing platform with strong future potential.The work was commissioned by the consulting firm Syncore Technologies AB at their office in Mjärdevi, Linköping. The project has, in total, taken 10 weeks and occurred during spring 2010.In this bachelor thesis a complete prototype of an industrial vibration measurement platform has been developed. By measuring a number of variables such as acceleration, temperature and speed conclusions can be drawn on machinery health. The aim is to evaluate hardware and software solutions for a possible future product. Based on a requirement specification a proper hardware design has be developed. The hardware consists of a four-layer PCB with an ARM Cortex-M3 microcontroller and about 250 other components. The PCB was designed, assembled, tested and finally housed in a box. Measures have been taken to protect the prototype against external disturbances such as inappropriate supply voltages and transients on the input stages.Software has been written for the microcontroller to perform the various measurements required by the prototype. These include RMS, integration and filtering. Special attention was paid to the latter by implementing filters based on lattice wave digital structures. This structure results in a very efficient implementation. Consideration is taken to be able to generate arbitrary filters independent of the characteristics and design method. To save time the microcontroller implements all the algorithms without any floating point numbers.Furthermore, both hardware and software are adapted for future industrial use. The finished prototype supports a number of communication interfaces in which Modbus (RS-485) and current loop communication can be mentioned.The final result is a very good performing platform with strong future potential.The work was commissioned by the consulting firm Syncore Technologies AB at their office in Mjärdevi, Linköping. The project has, in total, taken 10 weeks and occurred during spring 2010.</p>

<p>It is very interesting to probe the rotational symmetry of semiconductor quantum dots for quantum information and quantum computation applications. We studied the effects of rotational symmetry in semiconductor quantum dots using configuration interaction calculation. Moreover, to compare with the experimental data, we studied the effects of hidden symmetry. The 2D single-band model and the 3D single-band model were used to generate the single-particle states. How the spectra affected by the breaking of hidden symmetry and rotational symmetry are discussed. The breaking of hidden symmetry splits the degeneracy of electron-hole single-triplet and triplet-singlet states, which can be clearly seen from the spectra.</p><p>The breaking of rotational symmetry redistributes the weight percentage, due to the splitting of p_x and p_y states, and gives a small brightness to the dark transition, giving rise to asymmetry peaks. The asymmetry peaks of 4X, 5X, and 6X were analyzed numerically. In addition, Auger-like satellites of biexciton recombination were found in the calculation. There is an asymmetry peak of the biexciton Auger-like satellite for the 2D single-band model while no such asymmetry peak occurs for the 3D single-band model. Few-particle effects are needed in order to determine the energy separation of the biexciton main peak and the Auger-like satellite.</p><p>From the experiments, it was confirmed that the lower emission energy peak of X^2- spectrum is split. The competed splitting of the X^2- spectra were revealed when temperature dependence was implemented. However, since the splitting is small, we suggest the X^2- peaks are broadened in comparison with other configurations according to single-band models. Furthermore, the calculated excitonic emission patterns were compared with experiments. The 2D single-band model fails to give the correct energy order of the peaks for the few-particle spectra; on the other hand the peaks order from 3D single-band model consistent with experimental data.</p>

<p>Denna rapport behandlar en energiundersökning av värmekablar på uppdrag av INEOS ChlorVinyls anläggning i Stenungsund. Eftersom miljön får en större och större betydelse i dagens samhälle försöker alla sektorer i samhället minska sin energiförbrukning. År 2006 använde svensk industri 157 TWh energi och 35,8 % av detta var elenergi. Den kemiska industrin står för 8 % (2006) av Sveriges industriers energiförbrukning och räknas som en energiintensiv bransch. Fabriken i Stenungsund har länge haft ett mycket förmånligt elavtal vilket har gjort att de inte har varit lönsamt att bry sig om att göra relativt småskaliga effektiviseringar. Men nu med ökade energipriser är det aktuellt att titta på vad som kan göras och till vilket pris. Syftet med utredningen är att undersöka om ett annorlunda upplägg av termostaterna som styr värmekablarna gör att man kan spara energi genom att värmen bara ligger på när det verkligen behövs. Genom undersökning och jämförelse av olika termostater koms det fram till att det inte finns noggrannare termostater på marknaden än de som sitter i fabriken. Termostaten till VKB14 är dock felvald. Med hjälp av temperaturstatistik och ett medelvärde av antal timmar under en viss temperatur över de två vintersäsongerna har effektåtgången för VKA14 och VKB14 räknats ut. Genom mätningen av när kontaktorn slår till i VKB14 har det utlästs att detta skåp ligger till 38 % av tiden när temperaturen i intervallet är så hög att det inte borde vara till alls. Om man utgår från att skåpet gör av med 20 000 W när det är igång i onödan, ger detta att det förbrukar 1,3 gånger mer energi per år än vad som behövs vid en temperaturinställning på +5°C.</p>

<p>Det här examensarbetets syfte är att skapa en inspelningsstudio åt Strömkullegymnasiet i Bengtsfors. Det innefattar både akustik och teknik då båda delar är viktiga för resultatet av en inspelning. Elever och lärare på andra musikgymnasier har berättat hur studion fungerar på deras skolor och deras erfarenheter har varit till hjälp i det här arbetet. Den största utmaningen med projektet är att det inte finns någon lokal att bygga en studio i utan ett koncept som är flyttbart utan att man behöver påverka den gamla eller den nya lokalen måste utformas.</p><p>Projektet kunde inte slutföras då det inte är bestämt var studion ska placeras. Det har tillkommit alternativa lokaler som skiljer sig drastiskt från de två ursprungliga alternativen.</p> / <p>The purpose of this degree work is to help Strömkullegymnasiet in Bengtsfors to get a recording studio. It involves both the acoustics and the equipment because both parts are important to the outcome of a recording. Teachers and students from other music high schools have told how their studios works and their experience have been a good help for this report. The biggest challenge with this project is that it doesn’t exist a location where a studio can be built so a new moveable studio concept has to be developt that does not affect the new location.</p><p>The project couldn’t be completed because the decision where to locate the studio has not been taken. Some other locations is under investigation and they are a lot different from the original locations.</p>

Large-scale deployment of IEEE 802.11 wireless LANs (WLANs) remains a significant challenge. Many access points (APs) must be deployed and interconnected without a-priori knowledge of the demand. We consider that the deployment should be iterative, as follows. At first, access points are deployed to achieve partial coverage. Then, usage statistics are collected while the network operates. Overloaded and under-utilized APs would be identified, giving the opportunity to relocate, add or remove APs. In this thesis, we propose extensions to the WLAN architecture that would make our vision of iterative deployment feasible. One line of work focuses on self-configuration, which deals with building a WLAN from APs deployed without planning, and coping with mismatches between offered load and available capacity. Self-configuration is considered at three levels. At the network level, we propose a new distribution system that forms a WLAN from a set of APs connected to different IP networks and supports AP auto-configuration, link-layer mobility, and sharing infrastructure between operators. At the inter-cell level, we design a load-balancing scheme for overlapping APs that increases the network throughput and reduces the cell delay by evenly distributing the load. We also suggest how to reduce the handoff time by early detection and fast active scanning. At the intra-cell level, we present a distributed admission control that protects cells against congestion by blocking stations whose MAC service time would be above a set threshold. Another line of work deals with self-deployment and investigates how the network can assist in improving its continuous deployment by identifying the reasons for low cell throughput. One reason may be poor radio conditions. A new performance figure, the Multi-Rate Performance Index, is introduced to measure the efficiency of radio channel usage. Our measurements show that it identifies cells affected by bad radio conditions. An additional reason may be limited performance of some AP models. We present a method to measure the upper bound of an AP’s throughput and its dependence on offered load and orientation. Another reason for low throughput may be excessive distance between users and APs. Accurate positioning of users in a WLAN would permit optimizing the location and number of APs. We analyze the limitations of the two most popular range estimation techniques when used in WLANs: received signal strength and time of arrival. We find that the latter could perform better but the technique is not feasible due to the low resolution of the frame timestamps in the WLAN cards. The combination of self-configuration and self-deployment enables the autonomic operation of WLANs.

4H-SiC has physical properties supremely suited for a variety of high power, high frequency and high temperature electronic device applications. To fully take advantage of the material's potential, several problems remain to be solved. Two of the most important are (1) the characterization and understanding of crystallographic defects and their electrical impact on device performance, and (2) the introduction of acceptor dopants, their activation and control of the final distribution of charge carriers. Two main experimental methods have been employed in this thesis to analyze 4H-SiC material with respect to the issues (1) and (2): electron beam induced current (EBIC) and scanning spreading resistance microscopy (SSRM), respectively. EBIC yields a map of electron-hole-pairs generated by the electron beam of a scanning electron microscope and collected in the depleted region around a junction. EBIC is conducted in two modes. In the first mode the EBIC contrast constitutes a map of minority carrier diffusion lengths. Results from these measurements are compared to white beam syncrotron x-ray topography and reveal a one-to-one correlation between lattice distortions and the electron diffusion length in n+p 4H-SiC diodes. In the second EBIC mode, the junction is highly reverse biased and local avalanche processes can be studied. By correlating these EBIC results with other techniques it is possible to separate defects detrimental to device performance from others more benign. SSRM is a scanning probe microscopy technique that monitors carrier distributions in semiconductors. The method is for the first time successfully applied to 4H-SiC and compared to alternative carrier profiling techniques; spreading resistance profiling (SRP), scanning electron microscopy (SEM) and scanning capacitance microscopy (SCM). SCM successfully monitors the doping levels and junctions, but none of these techniques fulfill the requirements of detection resolution, dynamic range and reproducibility. The SSRM current shows on the other hand a nearly ideal behavior as a function of aluminum doping in epitaxially grown samples. However, the I-V dependence is highly non-linear and the extremely high currents measured indicate a broadening of the contact area and possibly an increased ionization due to sample heating. Finite element calculations are performed to further elucidate these effects. SSRM is also applied to characterize Al implantations as a function of anneal time and temperature. The Al doping profiles are imaged on cleaved cross-sections and the measured SSRM current is integrated with respect to depth to obtain a value of the total activation. The evaluation of the annealing series shows a continuous increase of the activation even up to 1950 °C. Other demonstrated SSRM applications include local characterization of electrical field strength in passivating layers of Al2O3, and lateral diffusion and doping properties of implanted boron.

In this thesis, noise coupling simulation is introduced into the behavioral level. Methods and models for simulating on-chip noise coupling at a behavioral level in a design flow are presented and verified for accuracy and validity. Today, designs of electronic systems are becoming denser and more and more mixed-signal systems such as System-on-Chip (SoC) are being devised. This raises problems when the electronics components start to interfere with each other. Often, digital components disturb analog components, introducing noise into the system causing degradation of the performance or even introducing errors into the functionality of the system. Today, these effects can only be simulated at a very late stage in the design process, causing large design iterations and increased costs if the designers are required to return and make alterations, which may have occurred at a very early stage in the process. This is why the focus of this work is centered on extracting noise coupling simulation models that can be used at a very early design stage such as the behavioral level and then follow the design through the various design stages. To realize this, SystemC is selected as a platform and implementation example for the behavioral level models. SystemC supports design refinement, which means that when designs are being refined and are crossing the design levels, the noise coupling models can also be refined to suit the current design. This new way of thinking in primarily mixed-signal designs is called Behavioral level Noise Coupling (BeNoC) simulation and shows great promise in enabling a reduction in the costs of design iterations due to component cross-talk and simplifies the work for mixed-signal system designers. / Electronics Design Division

Optical fibre sensors can be used to measure a wide variety of properties. In some cases they have replaced conventional electronic sensors due to their possibility of performing measurements in environments suffering from electromagnetic disturbance, or in harsh environments where electronics cannot survive. In other cases they have had less success mainly due to the higher cost involved in fibre-optic sensor systems. Intensity modulated fibre-optic sensors normally require only low-cost monitoring systems principally based on light emitting diodes and photo diodes. The sensor principle itself is very simple when based on coupling between fibres, and coupling based intensity modulated sensors have found applications over a long time, mainly within position and vibration sensing. In this thesis new concepts and applications for intensity modulated fibre-optic sensors based on coupling between fibres are presented. From a low-cost and standard component perspective alternative designs are proposed and analyzed in order to find improved performance. The development of a sensor for an industrial temperature sensing application, involving aspects on multiplexing and fibre network installation, is presented. Optical time domain reflectometry (OTDR) is suggested as an efficient technique for multiplexing several coupling based sensors, and sensor network installation with blown fibre in micro ducts is proposed as a flexible and cost-efficient alternative to traditional cabling. A new sensor configuration using a fibre to a multicore fibre coupling and an image sensor readout system is proposed. With this system a high-performance sensor setup with a large measurement range can be realised without the need for precise fibre alignment often needed in coupling based sensors involving fibres with small cores. The system performance is analyzed theoretically with complete system simulations on different setups. An experimental setup is made based on standard fibre and image acquisition components, and differences from the theoretical performance are analyzed. It is shown that sub-µm accuracy should be possible to obtain, being the theoretical limit, and it is further suggested that the experimental performance is mainly related to two error sources: core position instability and differences between the real and the expected optical power distribution. Methods to minimize the experimental error are proposed and evaluated.