Abstract
In this thesis, we proposed an effective time and frequency synchronization scheme for IEEE 802.16e systems, and this synchronization scheme can be used in MIMO environment. The synchronization is accomplished sequentially by packet detection, CFO estimation, and symbol timing synchronization. The proposed packet detection method is accomplished by delay and correlating the received signal, then normalized the result and compared it with the threshold. We found the phase of the correlation result in the packet detection block, and used the phase to determine the CFO estimation. After compensating the CFO, we will doing the symbol timing synchronization. It can be performed by cross-correlating the received signal and the corresponding transmitted preamble. The proposed CFO estimation has three advantages over WiMAX system. First, the CFO estimation shows satisfactory performance even at a low SNR and rich multi-path MIMO environment. Second, the performance in MIMO channel are much better then those in SISO channel due to the diversity gain. Furthermore, the performance would not down when the speed is change, the characteristic is important to IEEE 802.16e which support mobility. To improve the synchronization system can be used in IEEE 802.16e system, we used the proposed synchronization scheme to determine the receiver BER. As the simulation result shows, no matter we use what kind of MIMO channel environment, the proposed synchronization scheme can provide efficient and accurate result in the IEEE 802.16e system.