Download or read book Realizing the Potential of Adaptive Transmission Techniques Through Long Range Prediction for Rapidly Time variant Fading Mobile Radio Channels written by Shengquan Hu and published by . This book was released on 2000 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 2002 IEEE International Symposium on Information Theory written by and published by . This book was released on 2002 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Analysis of Adaptive Transmission Aided by Long Range Channel Prediction for Realistic Single and Multi Carrier Mobile Radio Channels written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Reliable adaptive transmission for frequency selective mobile radio systems is addressed. In particular, we investigate adaptive channel loading for wireless Orthogonal Frequency Division Multiplexing (OFDM) systems and adaptive modulation aided by observations of another carrier (e.g, Frequency Division Duplex (FDD) channels). Adaptive transmission techniques, where the modulation size, coding rate, or other signal transmission parameters are dynamically adapted to the changing channel conditions, have recently emerged as powerful tools for increasing the data rate and spectral efficiency for wireless system. However, reliable adaptive transmission requires long-range prediction (LRP) of future channel state information (CSI) due to the variation of the wireless channel, which results in different channel conditions between the time of data transmission and the time of the channel estimation. We derive the minimum mean-square-error (MMSE) long range channel prediction method that utilizes the time and frequency domain correlation function of the Rayleigh fading channel. Since the channel statistics are usually unknown, reduced complexity robust prediction methods that can converge rapidly to the theoretical MMSE and do not require the knowledge of correlation functions are developed for OFDM channels and systems aided by observations of another carrier. Statistical model of the prediction error that depends on the frequency and time correlation is developed and is used in the design of reliable adaptive modulation methods. A standard sum-of-sinusoids Rayleigh fading channel model and a novel physical model based on the method of images augmented with diffraction are employed to test the prediction algorithm. This physical model can generate non-stationary datasets to test both the LRP and its application in adaptive transmission schemes. It is demonstrated that this physical model generates realistic datasets that closely resemble measured data, and the results of.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2004 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Long Range Fading Prediction and Realistic Physical Modeling to Enable Adaptive Transmission for Mobile Radio Networks written by and published by . This book was released on 2005 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The feasibility of adaptive transmission enabled by Long Range Fading Prediction (LRP) was investigated for rapidly varying fading channels encountered in peer-to-peer mobile communication systems. The LRP algorithms were tested using the standard Jakes model and the realistic physical model developed by the Principal Investigators. This research was an interdisciplinary effort in communication theory, physics, and signal processing. Correlated fading was exploited in the development of the LRP algorithm to enable adaptive modulation for a Frequency Hopping Spread Spectrum (FH/SS) mobile radio channel. Adaptive frequency diversity transmission for FH systems with partial band interference also was explored. Significant performance gains were demonstrated relative to non-adaptive methods. Efficient channel loading for wireless Adaptive Orthogonal Frequency Division Multiplexing (AOFDM) systems aided by robust LRP was investigated and reduced feedback techniques were developed. The bit rates approaching those of AOFDM with perfect knowledge of fading conditions were achieved. Several linear and nonlinear Multi-Access Interference (MAI) mitigation and frequency diversity combining transmitter precoding methods aided by the LRP were developed for the downlink of the Direct Sequence Spread Spectrum (DS/SS) systems. The proposed techniques were shown to improve upon previously proposed precoding and detection methods while providing the desired performance/complexity trade-off.
Download or read book Proceedings IEEE International Symposium on Information Theory written by and published by . This book was released on 2000 with total page 548 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Zu Wilhelm Weischedel written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance Analysis of Reliable Adaptive Transmission for Mobile Radio Slow Frequency Hopping Channels Aided by Long Range Prediction written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to correlated fading in frequency hopping (FH) wireless communication systems, it is possible to predict the future channel state information (CSI) for one frequency based on the channel observations of other frequencies. As a result, the performance of slow FH systems can be improved by utilizing adaptive transmission techniques. We propose the optimal Minimum Mean Square Error (MMSE) Long Range Prediction algorithm for slow FH systems that employ coherent detection. A recursive autocorrelation update method and a simplified prediction algorithm are explored to reduce the complexity. Statistical model of the prediction accuracy is developed and used in the design of the reliable adaptive transmission systems. We investigate the performance of adaptive transmission for high-speed data transmission in SFH systems based on the proposed Long Range Prediction algorithms. For slow frequency hopping communications in the presence of partial-band interference, we propose to employ adaptive transmitter frequency diversity and adaptive modulation to mitigate the effects of partial-band interference and fading. Both standard Jakes model and realistic physical model are used to test the performance. Analysis and simulation results show that significant performance gains can be achieved relative to non-adaptive methods.
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1999 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deterministic Modeling and Long Range Prediction of Fast Fading Channels with Applications to Mobile Radio Systems written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In wireless communication systems, the direct signal and the reflected signals form an interference pattern resulting in a received signal given by the sum of these components. They are distinguished by their Doppler shifts at the mobile. Since the parameters associated with these components are slowly varying, the fading coefficients can be accurately predicted far ahead. We introduced a novel algorithm for long range prediction of fading channels. This algorithm finds the linear Minimum MeanSquared Error (MMSE) estimate of the future fading coefficients given a fixed number of previous observations. We show that thesuperior performance of this algorithm is due to its longer memoryspan achieved by using lower sampling rate given fixed model orderrelative to the conventional (data rate) methods of fading prediction. This long range prediction capability for fading channels would provide enabling technology for accurate power control, reliable transmitter and/or receiver diversity, more effective adaptive modulation and coding and improvements in many other components ofwireless systems. In this thesis, we demonstrate that largeimprovements in the performance are possible for both flat and frequency-selective rapidly varying fading channels when the proposed prediction method is used. We illustrate the performance enhancements both at the transmitter and the receiver with both theoretical and simulation results.
Download or read book Mobile Fading Channels written by Matthias Pätzold and published by Wiley-Blackwell. This book was released on 2002-04 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mobile channel fading is a loss in transmission intensity caused by changes in the transmission medium. By dealing with the modelling, analysis and simulation of mobile fading channels this text provides a fundamental understanding of many issues in the area of mobile fading channel modelling.; The main topics addressed in the volume are: fundamentals of stochastic and deterministic channel models and modelling and simulation of frequency-nonselective and frequency-selective fading channels. The guide also features methods for the design and realization of efficient channel simulators and fast channel simulators and MATLAB-programs for the evaluation and simulation of mobile fading channels.
Download or read book Adaptive Transmission and Channel Modeling for Frequency Hopping Communications written by and published by . This book was released on 2009 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project focused on design of adaptive transmission methods enabled by the long range fading prediction (LRP) for several mobile radio systems. First, a new improved allocation algorithm was proposed for multicarrier code-division multiple access (MC-CDMA) system with adaptive frequency hopping. When combined with multiuser detection, the proposed system is very efficient in mitigating the fading and multi-access interference for realistic mobile radio channels.
Download or read book Single and Multicarrier Adaptive Transmission Systems with Long Range Prediction Aided by Noise Reduction written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive transmission methods have evolved as one of the key enabling technologies to meet the increasing demand for high-speed wireless data access services. In this dissertation, we address several adaptive transmission systems and techniques required for their implementation. First, we focus on multicarrier code-division multiple access (MC-CDMA) system with adaptive frequency hopping (AFH). A suboptimal water-filling (WF) channel allocation algorithm was previously proposed for the reverse link of this system. To overcome the limitations of the WF algorithm in the presence of fading-induced near-far problem, a new allocation algorithm is proposed and demonstrated to improve performance when the conventional matched filter (MF) receiver is employed. Moreover, the allocation methods are extended to accommodate multiuser detectors (MUDs) at the receiver for MC-CDMA system with AFH. It is demonstrated that the combination of the improved allocation algorithm and the linear MUDs is very efficient in mitigating fading and multi-access interference (MAI) for realistic mobile radio channels with correlated subcarriers, channel state information (CSI) mismatch, and imperfect power control. Numerical results show that the proposed adaptive transmission method has much greater system capacity than conventional non-adaptive MC direct-sequence (DS)-CDMA system. Second, the adaptive modulation (AM) system is investigated. To ensure high spectral efficiency (SE) for AM systems, the CSI needs to be predicted to compensate for the feedback and data processing delay and system constraints. The long-range prediction (LRP) method achieves high prediction accuracy at practical predication ranges when the signal-to-noise ratio (SNR) of the observations is sufficiently high. However, its accuracy degrades severely at low and medium SNR. Hence, the noise reduction (NR) techniques are required for the LRP to achieve the desired prediction accuracy. A novel data-aided noise reduction (DA.
Download or read book On the Achievable Rate of Stationary Fading Channels written by Meik Dörpinghaus and published by Springer. This book was released on 2013-07-15 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volumes discusses various aspects regarding the capacity/achievable data rate of stationary Rayleigh fading channels. First, it analyses bounds on the achievable data rate with zero-mean proper Gaussian input symbols, which are capacity achieving in the coherent case, i.e., in case of perfect channel knowledge at the receiver. These bounds are tight in the sense that the difference between the upper and the lower bound is bounded for all SNRs. The lower bound converges to the coherent capacity for asymptotically small channel dynamics. Furthermore, these bounds are extended to the case of multiple-input multiple-output (MIMO) channels and to the case of frequency selective channels. In a further part, the present work studies the achievable rate with receivers based on synchronized detection and a code-aided channel estimation. For a specific type of such a receiver an approximate upper bound on the achievable rate is derived. The comparison of this approximate upper bound and the achievable data rate with receivers using synchronized detection based on a solely pilot based channel estimation gives an approximate upper bound on the possible gain by using this kind of code-aided channel estimation in comparison to the conventional receiver using a solely pilot based channel estimation. In addition, the achievable data rate with an optimal joint processing of pilot and data symbols is studied and a lower bound on the achievable rate for this case is derived. In this context, it is also shown which part of the mutual information of the transmitter and the receiver is discarded when using the conventional receiver with synchronized detection based on a solely pilot based channel estimation.
Download or read book Adaptive Transmission Techniques for Fast Fading Channels written by Balkan Kecicioglu and published by . This book was released on 2011 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Mobile Radio Propagation Channel written by J. D. Parsons and published by . This book was released on 1992 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offers in-depth discussions of multipath phenomena and its effects on narrowband and wideband signals. Presents basic information about the mobile radio channel and introduces some fundamental VHF and UHF propagation. Surveys signal strength prediction methods applicable over irregular terrain and in urban, suburban and rural areas as well as methods of channel sounding and simulation.
Download or read book Transmission Loss Predictions for Tropospheric Communication Circuits written by Institute for Telecommunication Sciences and Aeronomy (U.S.) and published by . This book was released on 1967 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
