Browsing Elektrik-Elektronik Mühendisliği / Electrical - Electronics Engineering by Publisher "IEEE-INST Electrical Electronics Engineers Inc"
Now showing items 1-9 of 9
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A Mobile Channel Model for VLC and Application to Adaptive System Design
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2017)In this letter we propose a realistic channel model for visible light communication (VLC) assuming a mobile user. Based on non-sequential ray tracing we first obtain channel impulse responses for each point over the user movement trajectories and then express path loss and delay spread as a function of distance through curve fitting. Our results demonstrate large variations in received power. In system design this necessitates the use of adaptive schemes where transmission parameters can be selected ...
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A Reliable Successive Relaying Protocol
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2014)Successive relaying has recently emerged as an effective technique for cooperative networks and provides significant improvements in bandwidth efficiency over traditional relaying techniques ;however to achieve full-diversity the available successive relaying protocols generally assume noise-free sourcerelay and interference-free inter-relay channels. In this paper a novel successive relaying protocol is proposed for N-relay wireless networks by removing these optimistic assumptions. The proposed ...
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An Improved Adaptive Subspace Tracking Algorithm Based on Approximated Power Iteration
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2018)A subspace tracking technique has drawn a lot of attentions due to its wide applications. The main objective of this approach is to estimate signal or noise subspace basis for the sample covariance matrix. In this paper we focus on providing a fast stable and adaptive subspace tracking algorithm that is implemented with low computational complexity. An alternative realization of the fast approximate power iteration (FAPI) method termed modified FAPI (MFAPI) is also presented. Rather than solving ...
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Conditional Power and Rate Adaptation for MQAM/OFDM Systems Under CFO With Perfect and Imperfect Channel Estimation Errors
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2015)In this paper a new conditional power and rate adaptation scheme for orthogonal frequency-division multiplexing (OFDM) systems is proposed in the presence of carrier frequency offset (CFO) with perfect and imperfect channel state information (CSI). The conventional adaptive scheme is shown to be a special case of the conditionally adaptive scheme technique that enables the resulting nonconvex optimization problem which is solved in a feasible way. It leads to a solution for optimal power adaptation ...
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Design of Practical Broadband Matching Networks With Mixed Lumped and Distributed Elements
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2014)Computer-aided design (CAD) tools are always preferred for designing broadband matching networks. However these tools give excellent results when the suitable matching network topology and initial element values are provided. Therefore in this brief a new initialization algorithm is proposed to get suitable network topology and element values for CAD tools. Then the power transfer capability of the matching network can be improved by using any CAD tool. It is clear from the example studied that ...
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Joint Optimization of Wireless Network Energy Consumption and Control System Performance in Wireless Networked Control Systems
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2017)Communication system design for wireless networked control systems requires satisfying the high reliability and strict delay constraints of control systems for guaranteed stability with the limited battery resources of sensor nodes despite the wireless networking induced non-idealities. These include non-zero packet error probability caused by the unreliability of wireless transmissions and non-zero delay resulting from packet transmission and shared wireless medium. In this paper we study the ...
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Optical MIMO-OFDM With Generalized LED Index Modulation
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2017)Visible light communications (VLC) is a promising and uncharted new technology for the next generation of wireless communication systems. This paper proposes a novel generalized light emitting diode (LED) index modulation method for multiple-input-multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM)-based VLC systems. The proposed scheme avoids the typical spectrum efficiency losses incurred by time- and frequency-domain shaping in OFDM signals. This is achieved by exploiting ...
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Power and Rate Adaptation Based on CSI and Velocity Variation for OFDM Systems Under Doubly Selective Fading Channels
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2016)In this paper a novel joint continuous power and rate adaptation scheme is proposed fordoubly selective fading channels in orthogonal frequency division multiplexing (OFDM) systems based on terminal velocity and perfect or imperfect channel state information (CSI). The analysis and simulation results show that the continuous power and rate adaptation scheme is very effective and improve the performance of OFDM systems substantially under time-varying fading channels as compared with the traditional ...
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Sparse Channel Estimation and Equalization for OFDM-Based Underwater Cooperative Systemsw with Amplify-and-Forward Relaying
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Publisher and Date:(IEEE-INST Electrical Electronics Engineers Inc, 2016)This paper is concerned with a challenging problem of channel estimation and equalization for amplify-and-forward cooperative relay based orthogonal frequency division multi-plexing (OFDM) systems in sparse underwater acoustic (UWA) channels. The sparseness of the channel impulse response and prior information for the non-Gaussian channel gains modeled by an exact continuous Gaussian mixture (CGM) are exploited to improve the performance of the channel estimation algorithm. The resulting novel ...
