一种基于时频对偶特性的空频多普勒OFDM编码方案  

New Space-frequency-Doppler Coded OFDM Scheme Based on Time-frequency Duality

作　　者：朱江章[1] 文双春[2] 杜青松[2] 

机构地区：[1]中南林业科技大学电子与信息工程学院,湖南长沙410004 [2]湖南大学计算机与通信学院,湖南长沙410082

出　　处：《系统仿真学报》2008年第5期1265-1269,共5页Journal of System Simulation

基　　金：高等学校博士学科点专项科研基金(20040532005)

摘　　要：基于时频对偶特性,提出了时变Doppler衰落信道下空频多普勒OFDM(Orthogonal Frequency Division Multiplexing)编码的一种新方案。在时变信道Doppler基扩展(BEM,Basis Expansion Model)模型的基础上,利用时频对偶性及循环矩阵的对角化处理,实现了时变Doppler衰落信道的线性化变换。通过OFDM调制,利用矩阵分块方法对OFDM子载频分块并按块进行复正交编码设计,实现了一般性MIMO系统中的空频多普勒OFDM编码。采用前端星座预处理与空频多普勒OFDM编码级联的方法,从而实现了包括信道Doppler分集在内的系统全分集增益。理论分析及实验仿真表明,新编码方案能稳健有效地对抗信道Doppler衰落,具有更高的频带利用率及更低的误比特率。A new space-frequency-Doppler coded OFDM scheme over the time-variant Doppler fading channel was proposed. Based on the Basis Expansion Model （BEM）, linearized conversion over the time-variant Doppler fading channels was achieved via the time-frequency duality and the circulant matrix diagonalized processing. With OFDM module, grouping the subcarriers in OFDM through the block matrix method, and generalized complex orthogonal designed on the block subcarriers, space-frequency-Doppler coded OFDM for the general multiple input multiple output （MIMO） system was thus constructed. Furthermore, concatenating it with the signal constellation precoding, full diversity gains including the inherent channel Doppler diversity were achieved. Theory analytical and simulation results demonstrate that the proposed scheme can effectively and robustly combat the inherent Doppler fading with high bandwidth efficiency and even lower bit error ratio.

关 键 词：时频对偶性 线性化变换 矩阵分块 空频多普勒OFDM编码 星座预处理 全分集增益 

分 类 号：TN92[电子电信—通信与信息系统]