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1	A comparison of frequency offset estimation methods in Orthogonal Frequency Division Multiplexing (OFDM) systems Karaoglu, Bulent 12 1900 (has links) Approved for public release; distribution in unlimited. / OFDM is a modulation technique that achieves high data rates, increased bandwidth efficiency and robustness in multipath environments. However, OFDM has some disadvantages, such as sensitivity to channel fading, large peak to average ratio and sensitivity to frequency offset. The latter causes intercarrier interference (ICI) and a reduction in the amplitude of the desired subcarrier which results in loss of orthogonality. In this thesis, the effects of frequency offset are studied in terms of loss of orthogonality. A number of techniques for frequency offset estimation are presented and tested in computer simulations. / Lieutenant Junior Grade, Turkish Navy Multiplexing Space time codes Wireless communication systems Frequency Offset Coarse Frequency Offset Estimation Fine Frequency Offset Estimation IFFT(Inverse Fast Fourier Transform) FFT Cyclic Prefix MATLAB Preamble OFDM Symbol
2	Analysis of the effects of phase noise and frequency offset in orthogonal frequency division multiplexing (OFDM) systems Erdogan, Ahmet Yasin 03 1900 (has links) Approved for public release, distribution is unlimited / Orthogonal frequency division multiplexing (OFDM) is being successfully used in numerous applications. It was chosen for IEEE 802.11a wireless local area network (WLAN) standard, and it is being considered for the fourthgeneration mobile communication systems. Along with its many attractive features, OFDM has some principal drawbacks. Sensitivity to frequency errors is the most dominant of these drawbacks. In this thesis, the frequency offset and phase noise effects on OFDM based communication systems are investigated under a variety of channel conditions covering both indoor and outdoor environments. The simulation performance results of the OFDM system for these channels are presented. / Lieutenant Junior Grade, Turkish Navy Multiplexing Brownian motion processes Electrical engineering Frequency offset Phase noise Differential decoding IFFT (Inverse fast Fourier transform) Guard interval FFT MATLAB Additive white Gaussian noise (AWGN) Interleaver Deinterleaver Mobile channels Convolutional encoding Viterbi decoder Probability of bit error Weiner process

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A comparison of frequency offset estimation methods in Orthogonal Frequency Division Multiplexing (OFDM) systems

Analysis of the effects of phase noise and frequency offset in orthogonal frequency division multiplexing (OFDM) systems