Search results for "COD"
showing 10 items of 2985 documents
Syllabic composition and use frequency: how do they affect stress assignment? A comparison between slow readers and fluent readers
2013
Italian words can be stressed either on penultimate or antepenultimate syllables. In both cases, stress assignment is not predictable by rules, but requires a lexical check. Italian words with stress on the penultimate syllable are defined as regular because the proportion of these words is much larger than words with stress on the antepenultimate syllable, defined as irregular. We propose to investigate the influence (in terms of correct stress positioning) of different syllabic and stress structures during "decoding” by both slow readers and fluent readers. Forty-eight children, twenty-four slow and twenty-four fluent readers, decoded “target words” selected on the basis of frequency (hig…
Statistical Modeling and Analysis of Mobile-to-Mobile Fading Channels in Cooperative Networks Under Line-of-Sight Conditions
2009
Published version of an article from the journal: Wireless Personal Communications. The original publication is available at Springerlink. http://dx.doi.org/10.1007/s11277-009-9721-4 Recently, mobile-to-mobile (M2M) cooperative network technology has gained considerable attention for its promise of enhanced system performance with increased mobility support. As this is a new research field, little is known about the statistical properties of M2M fading channels in cooperative networks. So far, M2M fading channels have mainly been modeled under the assumption of non-line-of-sight (NLOS) conditions. In this paper, we propose a new model for M2M fading channels in amplify-and-forward relay lin…
Throughput and energy efficiency comparison of one-hop, two-hop, virtual relay and cooperative retransmission schemes
2010
Paper presented at the 2010 2010 European Wireless Conference. (c) 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works. Paper also available from the publisher: http://dx.doi.org/10.1109/EW.2010.5483469 Two main types of approaches exist for implementing cooperative communications at the MAC layer: virtual-hop relay and cooperative retransmission. While the virtual-hop relay schemes employ relay n…
Performance Analysis of Alamouti Coded OFDM Systems over Rayleigh Fading Channels Correlated in Space and Time
2010
Paper presented at the 2010 IEEE 71st Vehicular Technology Conference, Taipei.(c) 2010 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works. Paper also available from the publisher: http://dx.doi.org/10.1109/VETECS.2010.5493855 This paper deals with the performance analysis of Alamouti coded orthogonal frequency division multiplexing (OFDM) systems over time-varying multipath Rayleigh fading channels. I…
Level-crossing rate and average duration of fades of the envelope of mobile-to-mobile fading channels in K-parallel dual-hop relay networks
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE." Article also available from publisher: http://dx.doi.org/10.1109/WCSP.2009.5371574 This paper studies the fading behavior of narrowband mobile-to-mobile (M2M) fading channels in dual-hop distributed cooperative multi-relay systems under non-line-of-sight (NLOS) propagation conditions. M2M fading channels considered here are associated with amplify-and-forward …
Modeling and Performance Analysis of Energy Efficiency Binary Power Control in MIMO-OFDM Wireless Communication Systems
2011
Published version of an article in the journal:International Journal of Distributed Sensor Networks. Also available from Hindawi Publishing: http://dx.doi.org/10.1155/2011/946258 The energy efficiency optimization of the binary power control scheme for MIMO-OFDM wireless communication systems is formulated, and then a global optimization solution of power allocation is derived. Furthermore, a new energy efficiency binary power control (EEBPC) algorithm is designed to improve the energy efficiency of MIMO-OFDM wireless communication systems. Simulation results show that the EEBPC algorithm has better energy efficiency and spectrum efficiency than the average power control algorithm in MIMO-O…
Broadband wireless communication systems: Channel modeling and system performance analysis
2011
Ph.D. Thesis The University of Agder, Faculty of Engineering and Science Wideband channel modeling, which can accurately describe the most important characteristics of wideband mobile fading channels, is essential for the design, evaluation, and optimization of broadband wireless communication systems. In the field of wideband channel modeling, the tradeoff between the prediction accuracy and simulation efficiency has to be taken into account. On one hand, channel models should be as accurate as possible. On the other hand, channel models are supposed to be simple and easy to put into use. There are several commonly used approaches to channel modeling, e.g., measurement-based channel modeli…
Design of Mobile Radio Channel Simulators Using the Iterative Nonlinear Least Square Approximation Method with Applications in Vehicle-to-X Communica…
2015
Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, 2015 Vehicle-to-X (V2X) communication systems are expected to provide tremendous benefits associated with the safety and traffic efficiency on roads. The successful deployment of emerging technologies like V2X requires channel models accurately representing fading statistics in environments where those technologies are used. The accuracy is, of course, a major concern when adapting or developing a suitable channel model for test and evaluation purposes. However, it is also important to take into account the simplicity of a channel model, which is crucial for efficient numerical computations and computer…
Channel simulation models for mobile broadband communication systems
2009
Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, Grimstad, 2009 Mobile broadband wireless communication systems (MBWCS) are emerging as a solution to provide broadband services to users on the move. These systems are expected to operate in a wide variety of propagation scenarios, at different mobile speeds, and at various frequency bands. Under such a variety of requirements, flexible and efficient channel simulation models will prove fundamental for the laboratory analysis of MBWCS. Currently, most of the existing channel simulation models are either too complex as to allow for an efficient performance investigation of MBWCS, or they cannot be applie…
Investigation of data encryption impact on broadcasting visible light communications
2014
Este trabajo investiga el impacto de la encriptación y desencriptación de datos en un sistema de comunicaciones de luz visible (VLC) de difusión en interiores incrustado en la capa física. Se ha implementado el cifrado RSA para proporcionar una transmisión de datos segura en la capa física. El artículo muestra el rendimiento de la tasa de error de bits (BER) para los sistemas VLC seguros y no seguros (8 y 12 bits) para velocidades de datos de 2 y 12 Mbps. Para una BER de 10e-4 mostramos que hay penalizaciones de potencia de 2-4 dB con las VLC seguras. También se investiga el impacto de la longitud de la clave en la propagación del error y la penalización de potencia. EU Cost Action IC1101 T…