356,408 research outputs found

    Small aircraft cockpit electromagnetic interference due to UMTS signal propagation

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    This paper implemented a ray-tracing based algorithm to calculate the EMI generated inside an aircraft cabin with particular emphasis on flight critical equipment such as the cockpit avionics panel. The interference level caused by the deployment of a UMTS Node B antenna for the provision of passenger communication was computed. The model was employed to study the effects of the multipath electromagnetic propagation attained from positioning a Node B antenna in different locations inside a relatively small tunnel shaped fuselage with dense furnishings. The proposed framework is also able to provide an all-encompassing understanding of the generated EMI, whilst offering support for the development of conscientious network design in aircraft.peer-reviewe

    Minimization of Handoff Failure Probability for Next-Generation Wireless Systems

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    During the past few years, advances in mobile communication theory have enabled the development and deployment of different wireless technologies, complementary to each other. Hence, their integration can realize a unified wireless system that has the best features of the individual networks. Next-Generation Wireless Systems (NGWS) integrate different wireless systems, each of which is optimized for some specific services and coverage area to provide ubiquitous communications to the mobile users. In this paper, we propose to enhance the handoff performance of mobile IP in wireless IP networks by reducing the false handoff probability in the NGWS handoff management protocol. Based on the information of false handoff probability, we analyze its effect on mobile speed and handoff signaling delay.Comment: 16 Page

    Secrecy Wireless Information and Power Transfer in OFDMA Systems

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    In this paper, we consider simultaneous wireless information and power transfer (SWIPT) in orthogonal frequency division multiple access (OFDMA) systems with the coexistence of information receivers (IRs) and energy receivers (ERs). The IRs are served with best-effort secrecy data and the ERs harvest energy with minimum required harvested power. To enhance physical-layer security and yet satisfy energy harvesting requirements, we introduce a new frequency-domain artificial noise based approach. We study the optimal resource allocation for the weighted sum secrecy rate maximization via transmit power and subcarrier allocation. The considered problem is non-convex, while we propose an efficient algorithm for solving it based on Lagrange duality method. Simulation results illustrate the effectiveness of the proposed algorithm as compared against other heuristic schemes.Comment: To appear in Globecom 201

    GeoNotes: A Location-based Information System for Public Spaces

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    The basic idea behind location-based information systems is to connect information pieces to positions in outdoor or indoor space. Through position technologies such as Global Positioning System (GPS), GSM positioning, Wireless LAN positioning o

    Waveform Optimization for Wireless Power Transfer with Nonlinear Energy Harvester Modeling

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    Far-field Wireless Power Transfer (WPT) and Simultaneous Wireless Information and Power Transfer (SWIPT) have attracted significant attention in the RF and communication communities. Despite the rapid progress, the problem of waveform design to enhance the output DC power of wireless energy harvester has received limited attention so far. In this paper, we bridge communication and RF design and derive novel multisine waveforms for multi-antenna wireless power transfer. The waveforms are adaptive to the channel state information and result from a posynomial maximization problem that originates from the non-linearity of the energy harvester. They are shown through realistic simulations to provide significant gains (in terms of harvested DC power) over state-of-the-art waveforms under a fixed transmit power constraint.Comment: paper to be presented at IEEE International Symposium on Wireless Communication Systems (ISWCS 2015
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