The objectives of this thesis are to measure the frequency noise of a widely tunable semiconductor laser, determine the main causes for the frequency uctuations and investigate the requirements for laser frequency noise for mQAM modulation formats by means of simulations. The following theoretical aspects are covered: the derivation of the frequency noise spectrum and the detuned loading effect from the rate equations; the shape and the causes of the frequency noise power spectral density; the derivation of the linewidth spectrum from white and 1/f frequency noise; the functionality of the laser and feedback loop used for the measurements. Measurements using the feedback loop showed substantial improvements in the -3 dB laser line width, but further investigation is needed in order to obtain a laser that is suitable both as a transmitter and as a local oscillator in coherent communication. Simulations outlined the dependence of linewidth, constellation diagrams and symbol error rates on frequency noise, for BPSK, QPSK, 8PSK modulation formats and their respective differential formats.

Recent developments in energy harvesting techniques allowed implementation of completely autonomous biosensor nodes. However, an energy harvesting device generally demands a customized power management unit (PMU) in order to provide the adequate voltage supply for the biosensor. One of the key blocks within this PMU is a regulation DC-DC converter. In this Master Thesis, the most relevant switched-capacitor DC-DC converter topologies that are suitable for biosensors are compared. The topology that can achieve the best efficiency and has the minimum area is chosen and designed. In order to maintain the supply voltage of the biosensor constant when the input voltage and the output current vary, a traditional Pulse-Frequency-Modulation (PFM) control is employed. An ultra-low-power PFM control circuit is designed to operate in weak inversion region. The post-layout simulations show that the designed DC-DC converter can provide an output voltage of 900mV when the output current varies between 5μA and 40μA. Additionally, the post layout simulations of the entire system, which includes the DC-DC converter and PFM control, show that the selected topology can achieve 87% peak efficiency, when the control losses are included. The main advantages of the proposed topology are its smaller chip area and its high efficiency during processing ultra-low power levels.

Development of software and strategies for prices, odds calculation, and risk management in the stock market and the soccer betting industry involves testing functionality using recorded real-world data. This process is called backtesting. If a system for backtesting is represented by software that is run on a single workstation then due to the complexity of mathematical computations, amount of recorded data and variety of strategies — backtesting can require significant amount of wall time. This is a problem because the development cycle increases in time. This paper proposes a design of a distributed system for backtesting that distributes the workload among available workstations considering limitations on the network usage.

The electrical performance of Silicon-On-Insulator (SOI) devices can be dramatically enhanced in terms of reduced parasitic capacitances, leakage current and power consumption. On the other hand, self-heating effects (SHE) are more pronounced than in a bulk device because of the buried oxide which limits power dissipation through the substrate. This issue is particularly important in the design of power amplifiers (PAs) for mobile applications where excellent RF performance is required while at the same time the current carrying capability of the devices have to be very high. In the present work the thermal behavior of multi-finger FDSOI-MOSFET power amplifiers has been investigated and thermal design guidelines have been proposed. Nano-scale thermal conduction and heat generation in nano-devices have been preliminarily studied in order to account for nano-scale effects. A finite element analysis model (FEA model) has been realized in the COMSOL multi-physics environment. Thermal simulations have been performed and the thermal behaviour of the simulated devices with respect to geometrical parameters has been studied. Based on the simulation results, thermal design guidelines have been proposed and a PA unit cell design has been presented. LVT device having a pitch p = 130nm has found to be the best choice for the design of a multifinger MOSFET power amplifier and it has been adopted as the core for the design of a unit cell. Such a unit cell has been used for the design of a power amplifier to be manufactured in the first tape-out for the Dynamic-ULP project.

The SGSN-MME node, which is important in wireless networks, handles many users and therefore the uptime requirements for it are very high. The goal at Ericsson is to reach 99.9999% uptime for their SGSN-MME nodes and to reach this a lot of testing is required. Therefore the test process during the SGSN-MME development is both resource expensive and time consuming. To optimize both resource utilization and test runtimes a common test node pool solution for their different test tools has been proposed. During this thesis a first exploratory investigation about how to optimize such a solution was made. During the investigation different aspects were evaluated and a first input about how an optimal solution can be implemented is proposed. By having a scheduling layer in the common node pool, which determines how many nodes each regression job will get, depending on current load, the number of test cases in the job and the current node utilization optimized solutions can be found. Future work in the area is still needed, but the exploratory research made during this thesis will give a good base to continue from.

Sensor data analysis at Scania deal with large amount of data collected from vehicles. Each time a Scania vehicle enters a workshop, a large number of variables are collected and stored in a RDBMS at high speed. Sensor data is numeric and is stored in a Data Warehouse. Ad-hoc analyses are performed on this data using Business Intelligence (BI) tools like SAS. There are challenges in using traditional database that are studied to identify improvement areas. Sensor data is huge and is growing at a rapid pace. It can be categorized as BigData for Scania. This problem is studied to define ideal properties for a high performance and scalable database solution. Distributed database products are studied to find interesting products for the problem. A desirable solution is a distributed computational cluster, where most of the computations are done locally in storage nodes to fully utilize local machine’s memory, and CPU and minimize network load. There is a plethora of distributed database products categorized under NoSQL and NewSQL. There is a large variety of NoSQL products that manage Organizations data in a distributed fashion. NoSQL products typically have advantage as improved scalability and disadvantages like lacking BI tool support and weaker consistency. There is an emerging category of distributed databases known as NewSQL databases that are relational data stores and they are designed to meet the demand for high performance and scalability. In this paper, an exploratory study was performed to find suitable products among these two categories. One product from each category was selected based on comparative study for practical implementation and the production data was imported to the solutions. Performance for a common use case (median computation) was measured and compared. Based on these comparisons, recommendations were provided for a suitable distributed product for Sensor data analysis.

Mobile payments are an emerging trend and an alternative to traditional payment methods. Mobile payments involve the usage of the mobile phone to handle credit transfers during purchase of goods and peer to peer money transfers referred to as mobile wallet service, instead of depending on bank cards and cash. In this scenario, while the mobile wallet industry still being in its infancy there exist a few drivers of mobile wallet solutions aiming to create a de-facto standard in the mobile market. The major drivers of mobile wallets can be attributed to Mobile Network Operators (MNOs), banks and web based companies.   In this report we would compare the motive behind every driver’s intent to enter the mobile payment market and the challenges associated in providing the wallet service to the market and assimilate the similarities and differences that exist among them. The key technical aspect behind the comparative analysis involves a standard set of factors on which the analysis would be based upon. The results obtained from the comparative analysis emphasizes on the significance behind the origin of industry of each mobile payment driver. The results also enlighten the varied yet partially coinciding objectives of each mobile payment driver.   The approach adopted to conduct this research is primarily through analyzing different origin industry based mobile wallet drivers, and then generalizing the data based on the researched use case models. The comparative analysis performed is based on the generalized data obtained by studying the use case under each mobile payment driver. Further, to predict the future marketing strategy of each driver, ansoff matrix is employed to devise the roadmap. Finally the main objective of the investigation is answered, which is finding out the reasons behind the entry of different industry origin drivers into the mobile payment market and the challenges faced by them.

Indoor solutions as a part of cellular mobile networks planning have been used for years in a way to fulfill the lack of admissible coverage while subscribers experienced using cellular phones indoors. On the other hand, network capital and operational expenditures; that has also commonly been used for Distributed Antenna Systems (DAS) solutions in indoor deployments. Besides sharing, outsourcing network operation and maintenance has also been widely accepted by wireless carriers all around the world after that IT outsourcing flow, which started in late 90s, seemed to be quite promising for lowering operational costs. The raise of new technologies in this domain that always promise higher, better and more to subscribers, little by little started to become worrisome since operators have begun to experience lower revenues from voice services during the last couple of years as well as higher demand of capacity. As a result, operators started considering deploying indoor networks as a part of their planned network, with regard to the fact that during recent years the femtocell technology became the hot topic for smallcell deployments. This way, MNOs could exploit benefits of covering customers indoors efficiently as well as offloading mobile data traffic from macro cellular networks. But a question rose afterwards; why sharing and outsourcing in smallcell networks have not taken off yet? As they have been commonly used in macro cellular networks and DAS solutions? In this MSc thesis, cooperation between different actors of the shared indoor mobile network ecosystem is studied by investigating both possible sharing models and the concept of outsourcing network operation and management for smallcell networks. This investigation has been done based on femtocells as the most suitable technology both for better coverage and higher capacity. During this process, different roles of actors in the ecosystems, the business relations between them and the main drivers of sharing were studied as well as discussing the main beneficiary of sharing, in order to find different types of cooperation and correlation in the ecosystem. The main research questions in the thesis revolve around absence of sharing either active or passively in indoor mobile networks as well as outsourcing network operation and management. Eventually, a series of possible deployment models for shared and outsourced indoor mobile networks are presented where they have been tried to be verified by a number of use cases. As a result, this study proposes a set of recommendations for different possible operators in the ecosystem in order to formulate a profitable business model for them. These recommendations are believed to enable taking of f sharing and outsourcing in smallcell networks.

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Ethernet has become more and more popular in the industrial world. The full duplex standard and the arrival of switches have made this protocol competitive for real-time purposes. In automation systems, a lot of energy is invested to integrate technologies using Ethernet into control systems. Since Ethernet frames have an important payload, and control signals a very small size, monopolizing an Ethernet frame for a single signal is quite inefficient. A solution to reduce this overhead is to allow sending several signals into the same Ethernet frame. This problem, close to the bin packing problem, is NP-hard. With signals having end-to-end deadlines to respect and different periods and release times, this problem becomes even more complex. We propose here to design a communication framework realizing such a frame packing. The challenge is to generate near-optimal solutions in terms of bandwidth utilization while meeting the different real-time constraints related to automation control systems.