OFDM系统非平稳相关散射突变信道的表示与估计

项目名称： OFDM系统非平稳相关散射突变信道的表示与估计

项目编号： No.61271213

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 无线电电子学、电信技术

项目作者： 方勇

作者单位： 上海大学

项目金额： 75万元

中文摘要： 高铁环境下的无线信道具有非广义平稳相关散射突变特性，目前广泛研究的广义平稳非相关散射快衰落信道估计技术不可能实现对此类突变信道的表示与估计，严重制约了下一代移动通信系统对高速移动环境的全覆盖。本项目对OFDM系统非广义平稳相关散射突变信道进行研究，分析其时变统计特性及非平稳衰落过程引起ICI的机理，探索其可压缩稀疏表示方法，建立信道估计理论。利用多场景马尔科夫链生灭过程进行突变信道统计描述和时变分析，构造局部散射和信道相关函数刻画时频独立的平均散射功率，使突变信道退化为局部低度双扩展信道，通过时频随机信道核建立突变信道的可压缩时频空稀疏模型，结合天线数估计与时延检测对等效模型进行补偿，利用群正交匹配实时追踪和估计信道核，以能量有限原则对CIR进行联合重构，实现突变信道的准确估计，并设计相应的快速算法。本项目研究可获得OFDM系统突变信道估计理论与方法，为高铁宽带接入提供理论基础和方法支撑。

中文关键词： OFDM；非广义平稳相关散射；可压缩稀疏表达；信道估计；系统优化

英文摘要： In broadband orthogonal frequency-division multiplexing (OFDM) wireless systems, the fading process under extremely high mobility is not expected to fulfill the wide-sense stationarity uncorrelated scattering (WSSUS) assumption. To alleviate this problem, channel estimation is adopted at the receiver as the critical technique to combat the impact brought to the signals by such Non-WSSUS transient channels. However, current channel estimation methods are not designed for such Non-WSSUS channel, thereby seriously hindering the development of the broadband wireless access for extremely high mobility applications. In this project, Non-WSSUS transient channel is studied for OFDM systems. First, the time-varying statistical characteristics of transient channel is investigated and the mechanism which causes the inter-carrier interference (ICI) in transient channel is analyzed; further, a compressive and sparse expression of transient channel is explored; finally, a series of channel estimation theroy is established for applications under extremely high mobility. Specifically, Markov chain and birth-death process based multi-scenario time-varying channel analysis is developed to describe the statistical characteristics of transient channel; local scattering function (LSF) and the generalized channel correlation (GCC) fu

英文关键词： OFDM；Non-WSSUS；Compressed sparse representation；Channel estimation；System optimazation