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This paper investigates linear precoding over nonsingular linear channels with additive white Gaussian noise, with lattice-type inputs. The aim is to maximize the minimum distance of the received lattice points, where the precoder is subject to an energy constraint. It is shown that the optimal precoder only produces a finite number of different lattices, namely perfect lattices, at the receiver.
Service discovery is central in pervasive middleware systems, built on top of the communication substrate using the more fundamental mechanisms for device discovery. In mobile pervasive systems devices come and go, and switch network frequently, demanding support for device discovery across heterogeneous networks. We present the design of a device discovery mechanism for the PalCom middleware that
Determining requirements process efficiency, and measuring the corresponding monetary impacts, is a challenging but necessary aspect of project management. In this paper, we perform an independent analysis of scoping decisions from a large industrial project with the goal of providing visualizations that facilitate investigations of process efficiency, agility, and the effects of scoping decisions
Software failures in medical devices can lead to catastrophic situations. Therefore is it crucial to handle software related risks when developing medical devices. This paper presents the experiences gained from an ongoing case study with a medical device development organisation. This part of the study focuses on the two first steps of the risk management process, i.e. risk identification and ris
A VCO is implemented in an RF 90 nm CMOS process and covers the frequency range 2.55-4.08 GHz. Drawing 19 mA from 1.2 V, the phase noise at 20 MHz frequency offset from a 3.7 GHz carrier is -156 dBc/Hz, meeting the phase noise requirement for GSM/EDGE and SAW-less WCDMA transmitter after frequency division by 2 or by 4. A second version of the VCO covers an additional 4.90-5.75 GHz range, at the e
Abstract in UndeterminedIn this paper, a number of channel estimation algorithms for iterative receivers are compared for the case of an up-link orthogonal frequency division multiplexing interleave division multiple access (OFDM-IDMA) system. Both pilot based algorithms, used to obtain an initial estimate, as well as semi-blind decision-directed algorithms working as a component of the iterative
Designing decorrelated MIMO antennas in small mobile terminals at frequencies below 1 GHz is challenging since more than one antenna tend to excite the single resonant mode available to a typical chassis structure. This challenge increases even further when multiple frequency bands are required from each antenna. Recently, a design framework to obtain efficient and decorrelated MIMO antennas based
The development of scientific software has similarities with processes that follow the software engineering "agile manifesto": responsiveness to change and collaboration are of utmost importance. But how well do current scientific software-development processes match the practices found in agile development methods, and what are the effects of using agile practices in such processes?
Vehicular communication channels are characterized by a non-stationary time- and frequency-selective fading process due to fast changes in the environment. We characterize the distribution of the envelope of the first delay bin in vehicle-to-vehicle channels by means of its Rician $K$-factor. We analyze the time–frequency variability of this channel parameter using vehicular channel measurements a
This paper presents a wireless receiver frontend intended for cellular applications implemented in a 65 nm CMOS technology. The circuit features a low noise amplifier (LNA), quadrature passive mixers, and a frequency divider generating 25 % duty cycle quadrature local oscillator (LO) signals. A complementary common-gate LNA is used, and to meet the stringent linearity requirements it employs posit
The present study deals with Elastic Flow Rerouting (EFR)-an original traffic restoration strategy for protecting traffic flows in communication networks (including wireless networks) against multiple link failures. EFR aims at alleviating the trade-off between practicability of traffic restoration and the cost of network resources observed in existing networking solutions. We present an extension
We present a method to compute, quickly and efficiently, the mutual information achieved by an independent identically distributed (IID) complex Gaussian signal on a block Rayleigh-faded channel without side information at the receiver. The method accommodates both scalar and multiple-input multiple-output (MIMO) settings. Operationally, this mutual information represents the highest spectral effi
A Digitally Controlled Oscillator (DCO) whose power consumption can be reconfigured while maintaining an almost constant phase-noise figure-of-merit (FoM). This is achieved by using either a single-switch-pair or a complementary (i.e., double-switch-pair) oscillator topology, without disturbing the optimized LC tank of the DCO. The optimal power consumption in the complementary (P-N) configuration
Context.Innovation is promoted in companies to help them stay competitive. Four types of innovation are defined: product, process, business, and organizational. Objective. We want to understand the perception of the innovation concept in industry, and particularly how the innovation types relate to each other. Method. We launched a survey at a branch of a multi-national corporation. Results. From
Abstract in UndeterminedA millimeter-wave (mm-wave) impulse radio is an attractive alternative to existing high-speed mm- wave radio systems because of the potential for a simpler transceiver architecture. This paper studies the feasibility of a mm-wave impulse radio system for home and office use by considering state-of-the- art transceivers and multiple-input multiple-output measured propagation
Open Source Software (OSS) created a paradigm shift within the software engineering field prompting further research to understand how mature, industry grade, software can be produced in an online milieu with distributed and lightly managed developers contributing source code in their free time. The OSS has become also a major revenue generator for many commercial organizations, and has found its
There has been extensive research about single link multiple-input multiple-output (MIMO) channels, both simulated and measured, but only a few studies have targeted multilink analysis with measured channel data. Hence, in this presented report, the authors analyse the influence of spatial separation of user terminals and the human shadowing effect on the MIMO capacity and on the signal-to-interfe
