A Novel ML Estimation of Time and Frequency Offset in the BPSK-OFDM System
| Autor: | Jia-Xing Li, 李佳興 |
|---|---|
| Rok vydání: | 2006 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 95 OFDM technique has advantages in providing a high data transmission capacity, being robust to the selective fading effects, combating inter-symbol interference (ISI), and so on. OFDM with above advantages becomes more significant in the future wireless communication systems. However, the knowledge of symbol timing offset and frequency offset are required for demodulation in OFDM systems. Previously, the ML estimation of timing and frequency offset in OFDM systems employing cyclic prefix has been presented with the assumption of independent identical distributed OFDM symbol samples. The information used to find the symbol synchronization depends on the length of cyclic prefix. Actually, the data in the BPSK-OFDM modulated symbol, transformed by inverse fast Fourier transform, is with a conjugate symmetry character. With this character, more information from the whole OFDM symbol could be provided for the estimation. In this thesis, a modified ML estimation employing the conjugate symmetry character of BPSK-OFDM symbol is derived to obtain the symbol timing and the frequency offset. The simulation results show that performances in terms of MSE of symbol timing and frequency offset for the proposed algorithm are better than those for the original ML estimation. . |
| Databáze: | Networked Digital Library of Theses & Dissertations |
| Externí odkaz: |
|