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Accurate modeling of electromagnetic wave propagation by means of ray tracing (RT) includes not only specular reflection, penetration through dielectric blocks and diffraction, but also diffuse scattering mechanisms. The accuracy, supported by a precise description of the environment, is achieved at a very high computational complexity. This computational complexity scales directly with the number
Based on static outdoor channel measurements we evaluate the influence of a vehicle on the MIMO radio channel, from a base station antenna array, to a multiple antenna handset in the hand of a user placed inside a test car. The measurement scenario is chosen to mimic a 2.6 GHz (LTE) macro-cell urban or rural scenario with two locations and orientations of the car, one at an open parking lot with a
A two-stage mm-wave power amplifier (PA) is presented. Designed in a 65 nm CMOS process, the PA employs capacitive neutralization in each stage for increased differential isolation and gain. Baluns are used for single-ended input/output signal to balanced signal conversion, and the interstage matching consists of a 2:1 transformer. With a 1.2 V supply, at 67 GHz, measurements show a gain of 16.8 d
The increasing number of mobile devices and high-speed services accelerate the growth of traffic in cellular backhaul networks. The traditional technologies used in the backhaul, copper, radio links and optical fibers, either cannot offer high data-rate, or are expensive. In this paper, we propose mixed integer programming models to facilitate upgrading the cellular backhaul using the free space o
We developed a mobile system for collecting and communicating heart rate data in real-time using low cost, commonly available equipment. This system could be used to monitor patients with cardiac arrhythmia over long periods of time, hopefully increasing the chance of capturing and recording an actual fibrillation, which rarely is the case today. Such recordings are useful for physicians to find t
Large-scale software development is a complex undertaking and generates an ever-increasing amount of information. To be able to work efficiently under such circumstances, navigation in all available data needs support. Maintaining traceability links between software artefacts is one approach to structure the information space and support this challenge. Several researchers have proposed traceabili
Context: Duplicate detection is a fundamental part of issue management. Systems able to predict whether a new defect report will be closed as a duplicate, may decrease costs by limiting rework and collecting related pieces of information. Goal: Our work explores using Apache Lucene for large-scale duplicate detection based on textual content. Also, we evaluate the previous claim that results are i
Age of Information (AoI) is a relatively new metric introduced to capture the freshness of a particular piece of information. While throughput and delay measurements are widely studied in the context of dense IEEE 802.11 Wireless LANs (WLANs) little is known in the literature about the AoI in this context. In this work we study the effects on the average AoI and its variance when a sensor node is
In this paper, we investigate the impact of power amplifier (PA) nonlinear distortion in pre-coded multi-user large antenna or massive MIMO downlink systems. First, detailed signal and system models are derived for the received signal at single-antenna user equipment (UE) under channel-aware linear precoding in the base-station combined with behavioral models for the individual PA units, covering
This paper presents a data-aided Carrier Frequency Offset (CFO) estimation algorithm targeting the Wideband OFDM systems. Utilizing 3 consecutive preambles and processing them at frequency domain, the algorithm is robust to both Frequency Independent (F-I) and Frequency Dependent (F-D) I/Q Mismatch (I/Q-M). To evaluate the effectiveness of the proposed CFO estimation technique, we conduct extensiv
An M-BCJR algorithm is proposed and tested over an AWGN channel with moderate to very intense intersymbol interference (ISI). Two M-BCJR applications are evaluated, simple detection over the ISI channel and turbo equalization. The signaling is binary faster than Nyquist linear modulation. The ISI models tested correspond to transmission of increasingly many bits/Hz-s with a fixed signal spectra; t
