Employ Cyclic Prefix to Improve Channel Estimation for the IEEE 802.11a System

• Main Authors: Ming-Chien Sun, 孫銘謙
• Other Authors: Tsung-Hsien Liu
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/27900228335536053918

碩士 === 國立中正大學 === 通訊工程研究所 === 92 === The orthogonal frequency division multiplexing (OFDM) technique is regarded as the most promising technique for the fourth generation wireless communication systems. The OFDM based system can provide high transmission rate with good spectrum efficiency. A important feature of an OFDM system is that the one-tapped equalizer is possible, which means very low computational complexity, for its baseband receiver. Among the various industrial standards, the IEEE 802.11a is most attractive for the wireless local area network (WLAN). This communication standard provides transmission rate up to 54 Mbps at 5 GHz band. The contribution of this thesis is to introduce a new channel estimation algorithm with very low computational complexity. This new algorithm applies maximum likelihood criterion and is believed to achieve the well-known Cramer-Rao lower bound. Unlike the traditional algorithm, this new algorithm uses the cyclic prefix information of the long training symbol.Simulation results are reported to show the improved performance of this new algorithm over the traditional one.