| 摘要(英) |
We use an antenna array to receive signals and control the direction of the maximum gain via different phase adjustment. The received signal is computed through beamforming algorithms which improve the SINR (Signal Interference Noise Ratio), increase the channel capacity, and enhance the quality of the communication. It also eliminates the effect of the multi-path through beamforing weights.In the pre-DFT beamformer, the received signal in the time domain is calculated by beamforming algorithms before DFT (Discrete Fourier Transform). Therefore, the complexity of computation will be lower because the DFT is only applied once.In the post-DFT beamformer, the processing of received signals is performed by beamforming algorithms after DFT. In this way, the complexity of post-DFT beamformer will be higher. However, its performance is much better than pre-DFT. In this thesis, we will analyze and compare post-DFT and pre-DFT beamformers for OFDM systems.We use three algorithms (MVDR, GSC, and Eigenvector) before DFT or after DFT, to analyze the performance. Finally, we will make the performance comparison with different angle of arrivals, numbers of multi-paths, and degree of interference signal strength. |
| 參考文獻 |
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