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Requirements Engineering has recently been greatly influenced by the way how firms use Open Source Software (OSS) and Software Ecosystems (SECOs) as a part of their product development and business models. This is further emphasized by the paradigm of Open Innovation, which highlights how firms should strive to use both internal and external resources to advance their internal innovation and techn
This paper presents preliminary results for a novel 128-antenna massive Multiple-Input, Multiple-Output (MIMO) testbed developed through Bristol Is Open in collaboration with National Instruments and Lund University. We believe that the results presented here validate the adoption of massive MIMO as a key enabling technology for 5G and pave the way for further pragmatic research by the massive MIM
This paper presents an adaptive QR decomposition (QRD) processor for five-band carrier aggregated LTE-Adownlinks. The design uses time and frequency correlationproperties of wireless channels to reduce QRD computationswhile maintaining an uncoded bit error rate loss below 1 dB.An analysis on the performance of a linear interpolating QRD ispresented and optimum distances for different channel condi
This work presents a broadband SiGe Power Amplifier (PA) for operation between 60-90 GHz covering both 71-76 GHz and 81-86 GHz E-Band sub-bands. It consists of a two-stage differential cascode amplifier using an LC-interstage matching network in the interface between the stages. Single-ended to differential conversion is accomplished by the use of two stacked 1-To-1 transformers, achieving a simul
In the paper we introduce an optimization framework for traffic restoration in optical wireless networks. As such networks experience multiple partial link failures, we introduce a generic extension of restoration strategies developed for wired networks (that assume total link failures) which enables handling partial link failures as well. The particular traffic restoration strategy studied in the
The symmetric PMCHWT method of moments (MoM) impedance matrix allows for the characteristic modes (CMs) of a structure containing dielectric to be found. Recently, this impedance matrix was proven to provide non-real solutions which can be attributed to the MoM internal resonance problem. These internal resonances can be removed through different CM post-processing techniques. However, these studi
Feedback with carry shift registers (FCSRs) have previously been available in two configurations, the Fibonacci and Galois architectures. Recently, a generalized and unifying FCSR structure and theory was presented. The new ring FCSR model repairs some weaknesses of the older architectures. Most notably, the carry cell bias property that was exploited for an attack on the eSTREAM final portfolio c
Abstract in UndeterminedSignal detection algorithms providing likelihood informationfor coded spatial-multiplexing multiple-input multipleoutput(MIMO) wireless communication system pose a criticaldesign challenge due to their prohibitively high computationalcomplexity. In this paper, we present a low-complexity soft-outputdetection algorithm by adopting four implementation-friendlyalgorithm-level
This paper presents a study in which the specific activity of (14)C in hair has been investigated as an easily determined bio-indicator of the integrated (14)C exposure (over several months). The study includes 28 Swedish workers handling (14)C-labelled compounds, or working in a (14)C-enriched environment. Hair samples from personnel at a Swedish nuclear power plant showed very low levels of (14)
Landslides of contaminated soil into surface water represent an overlooked exposure pathway that has not been addressed properly in existing risk analysis for landslide hazard, contaminated land, or river basin management. A landslide of contaminated soil into surface water implies an instantaneous exposure of the water to the soil, dramatically changing the prerequisites for the mobilisation and
Given a set of commodities and a network where some arcs can fail while others are reliable, we consider a routing problem with respect to a survivability requirement that each commodity can be split among pairs of failure-disjoint paths. Two paths p and p′ form a pair of failure-disjoint paths if they share only reliable arcs. The same flow is sent over p and p′, but the flow sent on a common rel
In LTE base-stations, RoHC is a processingintensive algorithm that may limit the system from serving a large number of users when it is used to compress the VoIP packets of mobile traffic. In this paper, a hardware-software and a full-hardware solution are proposed to accelerate the RoHC compression algorithm in LTE base-stations and enhance the system throughput and capacity. Results for both sol
Case studies are largely used for investigating software engineering practices. They are characterized by their flexible nature, multiple forms of data collection, and are mostly informed by qualitative data. Synthesis of case studies is necessary to build a body of knowledge from individual cases. There are many methods for such synthesis, but they are yet not well explored in software engineerin
This brief presents a low-complexity system for digitally assisting a channel select filter (CSF) to mitigate both even- and odd-order nonlinearities. The proposed solution is scalable and can be utilized for nonlinearity mitigation in different analog transceiver blocks. The system consists of an auxiliary path with a low-resolution analog to digital converter (ADC) enabling digital recreation an
[Context and motivation] When developing software, coordination between different organizational units is essential in order to develop a good quality product, on time and within budget. Particularly, the synchronization between requirements and verification processes is crucial in order to assure that the developed software product satisfies customer requirements. [Question/problem] Our research
Regression testing is verifying that previously functioning software remains after a change. With the goal of finding a basis for further research in a joint industry-academia research project, we conducted a systematic review of empirical evaluations of regression test selection techniques. We identified 27 papers reporting 36 empirical studies, 21 experiments and 15 case studies. In total 28 tec
The proposed time-to-digital converter (TDC) arranges two Vernier gated-ring-oscillator (GRO) branches in a 2-dimension (2-D) fashion. All delay differences between X-axis phases and Y-axis phases (based on 2-D definition) can be used, rather than only the diagonal line. The large latency time inherited from Vernier structure is therefore dramatically reduced. The TDC is implemented in a 90nm CMOS
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
