Ofdm papr reduction with linear coding and codeword modification

Download
2005
Susar, Aylin
In this thesis, reduction of the Peak-to-Average Power Ratio (PAPR) of Orthogonal Frequency Division Multiplexing (OFDM) is studied. A new PAPR reduction method is proposed that is based on block coding the input data and modifying the codeword until the PAPR is reduced below a certain threshold. The method makes use of the error correction capability of the block code employed. The performance of the algorithm has been investigated through theoretical models and computer simulations. For performance evaluation, a new gain parameter is defined. The gain parameter considers the SNR loss caused by modification of the codeword together with the PAPR reduction achieved. The gain parameter is used to compare a plain OFDM system with the system employing the PAPR reduction algorithm. The algorithm performance is examined through computer simulations and it is found that power reductions around 2-3 dB are obtained especially for low to moderate number of channels and relatively strong codes.

Suggestions

Nonlinear image restoration
Ungan, Cahit Uğur; Demirbaş, Kerim; Department of Electrical and Electronics Engineering (2005)
This thesis analyzes the process of deblurring of degraded images generated by space-variant nonlinear image systems with Gaussian observation noise. The restoration of blurred images is performed by using two methods; a modified version of the Optimum Decoding Based Smoothing Algorithm and the Bootstrap Filter Algorithm which is a version of Particle Filtering methods. A computer software called MATLAB is used for performing the simulations of image estimation. The results of some simulations for various o...
Nonuform pulse repetition interval optimization for pulse doppler radars
Mercan, Hasan; Tanık, Yalçın; Department of Electrical and Electronics Engineering (2004)
In this thesis, a method of optimization of nonuniform pulse repetition interval for pulse Doppler radars is investigated. PRI jittering technique is used for the selection of inter-pulse intervals. An environment with white Gaussian noise and clutter interference is defined and applying generalized likelihood ratio test, a sufficient statistic function for the detection of the target is derived. The effect of jitter set selection on range and Doppler ambiguity resolution and clutter rejection is investigat...
Nonlinear estimation techniques applied to econometric problems
Aslan, Serdar; Demirbaş, Kerim; Department of Electrical and Electronics Engineering (2004)
This thesis considers the filtering and prediction problems of nonlinear noisy econometric systems. As a filter/predictor, the standard tool Extended Kalman Filter and new approaches Discrete Quantization Filter and Sequential Importance Resampling Filter are used. The algorithms are compared by using Monte Carlo Simulation technique. The advantages of the new algorithms over Extended Kalman Filter are shown.
Noncoherent differential demodulation of CPM signals with joint frequency offset and symbol timing estimation
Çulha, Onur; Tanık, Yalçın; Department of Electrical and Electronics Engineering (2011)
In this thesis, noncoherent differential demodulation of CPM signals with joint carrier frequency offset and symbol timing estimation is investigated. CPM is very attractive for wireless communications owing to major properties: good spectral efficiency and a constant envelope property. In order to demodulate the received CPM signal differentially, the symbol timing and the carrier frequency offset have to be estimated accurately. There are numerous methods developed for the purpose. However, we have not en...
Constructions of resilient boolean functions with maximum nonlinearity
Şahin, M. Özgür; Yücel, Melek D; Department of Electrical and Electronics Engineering (2005)
In this thesis, we work on the upper bound for nonlinearity of t-resilient Boolean functions given by Sarkar and Maitra, which is based on divisibility properties of spectral weights of resilient functions and study construction methods that achieve the upper bound. One of the construction methods, introduced by Maity and Johansson, starts with a bent function and complements some values of its truth table corresponding to a previously chosen set of inputs, S, which satisfies three criteria. In this thesis,...
Citation Formats
A. Susar, “Ofdm papr reduction with linear coding and codeword modification,” M.S. - Master of Science, Middle East Technical University, 2005.