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Successful development of software systems involves efficient navigation among software artifacts. However, as artifacts continuously are produced and modified, engineers are typically plagued by challenging information landscapes. One state-of-practice approach to structure information is to establish trace links between artifacts, a practice that is also enforced by several development standards

Optimization techniques always play an important role in designing high-performance wireless systems. This presented thesis studies a selected set of optimization problems for different kinds of wireless networks, making use of mathematical programming techniques to find optimal solutions and of efficient heuristics to find near-optimal solutions. The basic contribution of the thesis consists in a

Excitation of the chassis enables single-antenna terminals to achieve good bandwidth and radiation performance, due to the entire chassis being utilized as the main radiator. In contrast, the same chassis excitation phenomenon complicates the design of multiple antennas for MIMO applications, since the same characteristic mode of the chassis may be effectively excited by more than one antenna, lea

Solving partially observable Markov decision processes (POMDPs) typically requires reasoning about the values of exponentially many state beliefs. Towards practical performance, state-of-the-art solvers use value bounds to guide this reasoning. However, sound upper value bounds are often computationally expensive to compute, and there is a tradeoff between the tightness of such bounds and their co

This paper presents a new Hardware (HW) im- plementation proposal for Discrete Fourier Transform (DFT) based channel estimators. The presented algorithm uses the high time correlation property of the channel estimates to reduce the complexity and the power consumption by utilizing a lower number of bits for the FFT in the channel estimator, compared to a traditional approach. The idea is that the

The friction stir welding procedure to seal copper canisters requires variable power input throughout the 45 minute long weld cycle to keep the welding temperature within the process window. This is due to variable thermal boundary conditions throughout the weld cycle which, together with fast disturbances in the spindle torque, requires control of both the power input and the welding temperature

This paper presents a high throughput, low latency soft-output signal detector for a 4×4 64-QAM MIMO system. To achieve high data-level parallelism and accurate soft information, the detector adopts a node perturbation technique to generate a list of candidate vectors around Zero Forcing, ZF, result. Additionally a fast and hardware friendly node enumeration scheme is developed to significantly re

Successful coordination of Requirements Engineering and Testing (RET) is crucial in large-scale software engineering. If the activities involved in RET are not aligned, effort is inevitably wasted, and the probability of delivering high quality software products in time decreases. Previous work has identified sixteen challenges in aligning RET in a case study of six companies. However, all six cas

This paper presents a QVCO and divider for a 28 GHz SiGe PLL. It was designed in a SiGe process with fT= 200 GHz. The PLL is intended to be used for beam steering in an 81-86 GHz E-band transmitter. Phase control is implemented by programmable current injection into the loop filter. The simulations in Spectre use a layout extracted view with parasitics for the QVCO and the frequency divider and an

Next generation wireless systems have to be able to efficiently deal with fast fading environments in order to achieve high spectral efficiency. Using multiple-input multiple-output (MIMO) systems and exploiting receive diversity, their spectral efficiency can be greatly increased. Commonly, the channel is estimated via training symbols, before the data detection is carried out based on the previo

As massive MIMO is currently considered a leading 5G technology candidate, channel models that capture important massive MIMO channel characteristics are urgently needed. In this paper we present an attempt for massive MIMO channel modeling based on measurement campaigns at 2.6 GHz in both outdoor and indoor environments, using physically-large arrays and with closely-spaced users. The COST 2100 M

This paper presents low power hardware generation, based on a CAL actor language dataflow implementation. The CAL language gives a higher level of abstraction and generate both hardware and software description. The original CAL flow is targeted for hardware-software co-design of complex systems on FPGA. Modifications are done to the original CAL flow to facilitate low power ASIC implementations.

Antenna systems are provided including a chassi (115) and first and second radiating (110, 120) elements coupled to the chassi. The first radiating element is configured to amplify excitation of the chassi and the second radiating element is configured to reduce excitation of the chassi so as to reduce mutual coupling in the antenna system. Related co- located antennas and methods of controlling m

In this paper, we present a thin single-arm Archimedean spiral antenna designed to be used in underground soil measurements to characterize the dielectric properties of soil during freezing and thawing processes. The designed antenna works in low permittivity, low-loss frozen soil as well as in high permittivity, high-loss marshy soil and operates over the frequency range 1–3 GHz. The antennas has