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This thesis focuses on algorithms and proofs of concepts in the area of wireless systems operating with a large number of antennas, especially at the base station side.The first studied topic concerns the design and implementation of massive multiple-input multiple-output (MIMO) testbeds, primarily for communications. This is an entirely new engineering challenge on its own, due to the unprecedent

A fully automatic system for abdominal organ segmentation is presented. As a first step, an organ localization is obtained via a robust and efficient feature registration method where the center of the organ is estimated together with a region of interest surrounding the center. Then, a convolutional neural network performing voxelwise classification is applied. The convolutional neural network co

Background. Search and selection of primary studies in Systematic Literature Reviews (SLR) is labour intensive, and hard to replicate and update. Aims. We explore a machine learning approach to support semi-automated search and selection in SLRs to address these weaknesses. Method. We 1) train a classi er on an initial set of papers, 2) extend this set of papers by automated search and snowballing

Abundant data is the key to successful machine learning. However, supervised learning requires annotated data that are often hard to obtain. In a classification task with limited resources, Active Learning (AL) promises to guide annotators to examples that bring the most value for a classifier. AL can be successfully combined with self-training, i.e., extending a training set with the unlabelled e

In sensor network applications with low traffic intensity, idle channel listening is one of the main sources of energy waste. The use of a dedicated low-power wake-up receiver (WRx), which utilizes duty-cycled channel listening, can significantly reduce the idle listening energy cost. Extreme low-power design typically leads to performance losses, indirectly increasing energy costs. Striking the r

We consider designing demodulators for linear vector channels that use reduced-size trellis descriptions for the received signal. We assume an iterative receiver and use interference cancellation (IC) with soft-information provided by an outer decoder to mitigate the signal part that is not covered by a reduced-size trellis description. In order to reach a trellis description, a linear filter is a

We consider the potential for positioning with a system where antenna arrays are deployed as a large intelligent surface (LIS), which is a newly proposed concept beyond massive multi-input multi-output (MIMO) where future man-made structures are electronically active with integrated electronics and wireless communication making the entire environment "intelligent". In a first step, we derive Fishe

In this paper, we consider the potential of data-transmission in a system with a massive number of radiating and sensing elements, thought of as a contiguous surface of electromagnetically active material. We refer to this as a Large Intelligent Surface (LIS). The "LIS" is a newly proposed concept, which conceptually goes beyond contemporary massive MIMO technology, and arises from our vision of a

In this paper, we introduce the concept of spatially coupled turbo-like codes (SC-TCs) as the spatial coupling of a number of turbo-like code ensembles. In particular, we consider the spatial coupling of parallel concatenated codes, introduced by Berrou et al., and that of serially concatenated codes (SCCs), introduced by Benedetto et al. Furthermore, we propose two extensions of braided convoluti

Hsu–Kasami–Chien (HKC) are a class of cyclic codes that can correct either burst or random errors. This paper studies the maximum burst-correcting capability of HKC codes. A necessary and sufficient condition for a b- burst-correcting cyclic HKC code is given and simplified as a generalized one for Fire codes. An upper bound on the burstcorrecting capability of HKC codes is derived, which improves

The effect of a user’s body on channel characteristics for single user downlink transmission in an urban scenario for the 5th generation (5G) systems is investigated with ray-tracing at 15 GHz and 28 GHz. Three different designs of user equipment (UE) antennas are fabricated and integrated into a mobile phone prototype, and their 3D radiation patterns are measured both with and without

In this letter, the fading statistics of wireless channels in high-speed railway cutting scenarios are characterized based on measurements. A multiple scattering model called second-order scattering fading (SOSF) is used to model the small-scale fading considering the influence of cuttings and bridges. The SOSF model can offer the possibility of analytical estimation for different fading severitie

Radio-based localization has the potential to provide centimeter-level position information. In this paper we apply joint probabilistic data association to multipath-assisted simultaneous localization and mapping (SLAM) for this purpose. In multipath-assisted localization, position-related information in multipath components (MPCs) is exploited to increase the accuracy and robustness of indoor tra

Massive MIMO (MaMIMO) is a key technology for 5G wireless communication, enabling large increase in both spectral and energy efficiency at the same time. Before it can be deployed, it is important to find efficient implementation strategies. Because of the many antennas, an essential part of decreasing complexity, and further improving energy efficiency, is optimization of the digital signal proce

In this paper, we consider positioning with observed-time-difference-of-arrival (OTDOA) for a device deployed in long-term-evolution (LTE) based narrow-band Internet-of-things (NB-IoT) systems. We propose an iterative expectation- maximization based successive interference cancellation (EM-SIC) algorithm to jointly consider estimations of residual frequency- offset (FO), fading-channel taps and ti

Timely loss-of-contact detection between devices in pervasive systems using mobile networks is an important aspect for both functionality and user experience. Traditional schemes where time-to-live is defined by the service provider are not adequate in mobile networks where communication failures are frequent. On the other hand, schemes using keep-alive messaging tend to increase the communication

In this paper, we consider precoder design for multiuser multiple-input-multiple-output (MIMO) Gaussian broadcast (BC) channels and propose a generalized zero-forcing (GZF) precoder based on successive dirty-paper coding (DPC), i.e., the GZF-DP precoder. The GZF-DP precoder is an extension of the GZF-DP precoder designed earlier for multi-input-single-output broadcast (MISO-BC) channels, and also

Despite of having no explicit shape model, multi-atlas approaches to image segmentation have proved to be a top-performer for several diverse datasets and imaging modalities. In this paper, we show how one can directly incorporate shape regularization into the multi-atlas framework. Unlike traditional methods, our proposed approach does not rely on label fusion on the voxel level. Instead, each re

We consider the potential for positioning with a system where antenna arrays are deployed as a large intelligent surface (LIS). We derive Fisher-informations and Cram\'{e}r-Rao lower bounds (CRLB) in closed-form for terminals along the central perpendicular line (CPL) of the LIS for all three Cartesian dimensions. For terminals at positions other than the CPL, closed-form expressions for the Fishe

The concept of Channel Shortening (CS) is a well-known technique that has a rich history over 40 years. CS transfers linear vector channels such as multi-input multi-output (MIMO) and intersymbol interference (ISI) channels into ``shortened'' versions, for the purpose of reducing demodulation-complexity and improving data-transmission performance. The original CS idea can trace back to the minimum