星地链路高速数传系统快时变信道估计方法  

Channel Estimation Method for Time-selective Channel in Satellite-earth Link High Rate Data Transmission Systems

作　　者：张帅[1] 张晓林[1] 

机构地区：[1]北京航空航天大学电子信息工程学院,北京100191

出　　处：《遥测遥控》2013年第6期33-39,共7页Journal of Telemetry,Tracking and Command

摘　　要：针对星地链路高速数传系统中应用的时域同步正交频分复用(TDS-OFDM)技术,提出快时变信道估计方法及其改进方法。两种方法分别利用帧头求得帧头中一个或两个时间点的信道冲激响应,结合相邻两帧的信道变化率拟合整个帧体时间段的信道响应。利用帧头求信道响应不仅能适应TDS-OFDM结构,而且不存在频域导频系统中由于导频非均匀分布带来的能量泄漏。仿真结果表明,两种信道估计方法,特别是改进方法,能在更大的多普勒频率环境下,很好地拟合快时变信道的变化,在多径快时变信道下性能优越。The paper proposes a channel estimation method and its improved method for the TDS-OFDM technique used in the satellite-earth link high rate data transmission systems. In this paper,we propose a channel estimation method for TDS-OFDM systems to obtain the channel state information over time-selective channel. Moreover,we present an improved algorithm in order to deal with serve time selectivity. Both methods use a piece-wise linear model to approximate channel time-variations. The first method extracts channel time-variation information from the channel impulse response at the midpoint of pseudo-noise( PN)sequences. In its improved method,we are able to get more accurate estimation about the channel variations because channel impulse responses are estimated at two different points in every frame header. Simulations prove that the proposed two methods both have low complexity and work well under frequency and time selective fading channels.

关 键 词：星地链路 高速数传 TDS-OFDM 时变信道 信道估计 

分 类 号：TN911.23[电子电信—通信与信息系统]