Frequency Synchronization and Channel Estimation for OFDM Systems over Frequency-Selective Channels: ML and LS Approaches
| Autor: | Shang-Chieh Nan, 南尚傑 |
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| Rok vydání: | 2008 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 96 In this thesis, we first introduced the basic principle of the orthogonal frequency division multiplexing (OFDM) transmission and modulation technique. Second, we present a maximum-likelihood (ML) estimation algorithm for jointly estimate frequency offset and channel frequency response (CFR) for OFDM systems in frequency selective channels. Then, with proper approximations after frequency offset correction, a least squares approach is also used for channel estimation for comparison. The frequency offset may arise from both carrier frequency mismatch and Doppler spread effect. We use adaptive gradient search to estimate the frequency offset, the channel frequency response estimation is subsequently obtained. Simulation results of our proposed estimations show great estimation accuracies and are found in excellent agreements with theoretical predictions. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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