基于ieee 802.11a标准的ofdm信道估计技术研究与实现based on the ieee 802.11 a standard research and implementation of ofdm channel estimation technique.docx

东南大学硕士学位论文 摘要
摘 要
无线局域网是指以无线信道作为传输媒介的计算机局域网络。由于正交频分复用(OFDM) ·基于OFDM技术的无线局域网技术的研究和应用也正日益受到重视。本论文主要探讨无线局域网的若干关键技术,内容涉及基于IEEE 、信道均衡算法,自动增益控制算法,分组检测算法研究及实现方案。
在对OFDM信道估计算法的研究中发现,最小平方信道估计算法具有低的计算复杂度, 但是在低信噪比的情况下,容易受到加性噪声的影响,时域信道估计算法,基于最小均方准则的LMMSE算法,(SVD)算、,但是高的复杂性使得应用受到了限制。。和传统的最小平方的算法不同,两种新算往充分利用无线局域网环境下相邻子信道频域响应具有的相关性,对子载波的信道响应使用加权平滑处理,有效地消弱加性噪声对子信道频域响应的影响。,低信噪比的情况下表现出很好的MSE性能,较Ls算法有3dB的改善,其误比特率性能也比 Ls算法_f】IdB左右的改善。信道估计的结果用于对OFDM子载波信道响应进行补偿。也就是对接收数据的均衡。
器的低复杂性实现方案.
分组检测的准确率直接关系到无线局域网网络吞吐量,本文介绍了延时自相关分组检测算法及实现结构,分析了OFDM无线局域网数据分组前导训练符号的周期性特点,提出了一种适用丁=,并针对算洼的FPGA实现中汁算的简化处理进行了讨论。
关键词:无线局域网 止交频分复用IEEE 802 1 la信道估计均方误差自动增益控制分组检测
东南人学硕士学位论文 Abstr_aet
Abstract
Wireless local-work(WLANl is a type oflocal work that USeS high—f?equency radio waves rather than wires municate between nodes With high spectrum usage and immunity to multi—path frequency division multiplexing(OFDM)technology has
been widely used in many advanced munication research and application
of the OFDM wireless LAN technology is being paid more and more regard thesis is to make research on the key technologies of WLAN,and it includes the study and implementation schemes of OFDM channel estimation,channel equalization,automatic gain control aS well as package detection according to IEEE la standard.
During the study ofOFDM channel estimation algorithms,it is discovered that the least square
(LS)channel estimation algorithm has plexity while its perfbrmance decays when signal noise ratio(SNR)is low;the time·domain algorithm,Minimum Mean—Square Error algorithm, estimation algorithm based on FFT and singular value posation(SVD)have good performance,but the plexity limits the application This thesis proposes a smoothing scheme with plexity based on least squa