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The COST 2100 channel model is a geometry-based stochastic channel model (GSCM) that can reproduce the stochastic properties of multi-link Multiple-Input Mulitple-Output (MIMO) channels over time, frequency and space. By contrast to other popular GSCMs, the COST 2100 approach is generic and flexible, making it suitable to model multi-user or distributed MIMO scenarios. In this paper a concise over
Recent years have seen an increasing attention given to wireless Personal Area Networks (PANs), which are typically networks with small transmitter-receiver (TX-RX) separation. The desire for high data rates has led to an interest in deploying multiple-input multiple-output (MIMO) transmission for such systems, but up until this date there exists, to the authors’ best knowledge, no MIMO channel mo
We present a 2nd-order 4-bit continuous-time (CT) delta-sigma modulator (DSM) employing a 2nd-order loop filter with a single operational amplifier. This choice strongly reduces the power consumption, since operational amplifiers are the most power hungry blocks in the DSM. The DSM has been implemented in a 65 nm CMOS process, where it occupies an area of . It achieves an SNDR of 64 dB over a 500
Two studies of testing practices for software product lines identify gaps between required techniques and existing approaches in the available literature. This Web extra offers extra details for the main article (specifically, the bibliography for the two studies described).
Software product line engineering is an approach to cost-efficiently derive tailored products to markets and customers, utilizing common components and services in a planned manner. Product lines have been applied to other engineering fields for decades, while being quite recently introduced in software engineering. For software product lines, productivity gains are mostly related to the developme
A transceiver suitable for devices in wireless body area networks is presented. Stringent requirements are imposed by the high link loss between opposite sides of the body, about 85 dB in the 2.45 GHz ISM band. Despite this, minimum physical size and power consumption are required, and we target a transceiver with 1 mm2 chip area, 1 mW active power consumption, and data rate 250 kbit/s. The receiv
This paper presents two circuits, a complete 1.5 V 28 GHz SiGe beam steering PLL and a standalone 28 GHz QVCO with I/Q phase imbalance detection and compensation. The circuits were designed in a SiGe process with f T = 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 DC current injection at the output of a Gilbert archite
We consider channels affected by intersymbol interference with reduced-complexity, mutual information optimized, channel-shortening detection. For such settings, we optimize the transmit filter, taking into consideration the reduced receiver complexity constraint. As figure of merit, we consider the achievable information rate of the entire system and with functional analysis, we establish a gener
The paper is devoted to modeling and optimization of reliable wireless mesh networks that employ directional antennas. We introduce two mixed-integer programming formulations that allow to simultaneously characterize routing patterns and transmission schedules. The first model allows for maximizing the minimal flow in a network. The second model involves reliability constraints and aims at minimiz
Vehicle-to-vehicle (V2V) communications have received increasingattention lately, but there is a lack of reported results regarding important quantities such as path loss. This paper presents parameterized path loss models for V2V communications based on extensive sets of measurement data collected mainly under line-of-sight conditions in four different propagation environments: highway, rural, ur
Context. Development of safety-critical systems is mostly governed by process-heavy paradigms, while increasing demands on flexibility and agility also reach this domain. Objectives. We wanted to explore in more detail the industrial needs and challenges when facing this trend. Method. We launched a qualitative survey, interviewing engineers from four companies in four different industry domains.
[Context & motivation] Growing software companies with increasing product complexity face the issue of how to scale up their Requirements Engineering (RE) practices. In market-driven requirements engineering, release planning and scoping decisions are increasingly challenging as the size and complexity increases. [Problem] This paper presents initial results of an on-going exploratory, qualita
Climate and weather extremes are sporadically recurring events that may have major local or regional impacts on the society and the environment. These events are typically related to unusually high or low temperature, prolonged dry or wet conditions, heavy precipitation, or extreme winds. Extreme events are part of the overall climate and weather alongside average conditions and variability, and t
This paper presents a hardware architecture of pulse shaping filter used in multicarrier systems. The filter can be configured to be used for both transmitter and receiver with limited overhead. Generic implementation complexity analysis for a filter in a multicarrier system with N sub-carriers is presented, while the implemented architecture is for a system with 128 sub-carriers. The pulse shapin
Time-reversal (TR) signal processing has the potential to focus the transmitted signal at a desired receive (Rx) location in both space and time. At lower frequency bands, TR in conjunction with array antennas at transmit (Tx) or Rx has been shown to significantly improve its focusing performance relative to the case of single antennas at both link ends. This work for the first time investigates T
Optimization models related to designing and operating complex systems are mainly focused on some efficiency metrics such as response time, queue length, throughput, and cost. However, in systems which serve many entities there is also a need for respecting fairness: each system entity ought to be provided with an adequate share of the system's services. Still, due to system operations-dependant c
Open source components can be used as one type of software component in development of commercial software. In development using this type of component, potential open source components must first be identified, then specific components must be selected, and after that selected components should maybe be adapted before they are included in the developed product. A company using open source compone
Reference attribute grammars (RAGs) provide a practical declarative means to implement programming language compilers and other tools. RAGs have previously been extended to support nonterminal attributes (also known as higher-order attributes), circular attributes, and context-dependent declarative rewrites of the abstract syntax tree. In this previous work, interdependencies between these extensi
This paper presents the design of a digital PLL which uses a high resolution Gated-Ring-Oscillator-Based Vernier Time-to-Digital Converter (TDC) for low noise RF application. The TDC uses two gated ring oscillators (GRO) acting as the delay lines in an improved Vernier TDC. The already small quantization noise of the standard Vernier TDC is further first-order shaped by the GRO operation. Addition
Bug report assignment is an important part of software maintenance. In particular, incorrect assignments of bug reports to development teams can be very expensive in large software development projects. Several studies propose automating bug assignment techniques using machine learning in open source software contexts, but no study exists for large-scale proprietary projects in industry. The goal
