TDS-OFDM时变信道估计和均衡的BEM-LSQR方法  

TDS-OFDM Time Varying Channel Estimation and Equalization Using BEM-LSQR

作　　者：王亦之[1] 陈赟[1] 曾晓洋[1] 

机构地区：[1]复旦大学专用集成电路与系统国家重点实验室,上海201203

出　　处：《复旦学报（自然科学版）》2013年第3期328-333,共6页Journal of Fudan University：Natural Science

基　　金：十一五重大专项资助项目(2009ZX01031-002-003-2);国家"863"高技术研究发展计划重点项目(SQ2008AA01ZX1480432);新一代宽带无线移动通讯网重大专项资助项目(2011ZX03003-003-03);国家重点实验室重点资助项目(11ZD0005);上海市教育委员会曙光计划资助项目(11SG07)

摘　　要：中国地面高清数字电视(DTMB)在高速移动环境下的应用日益广泛.利用其多载波模式下的时域同步正交频分复用(TDS-OFDM)帧结构,提出三种利用基展开模型(BEM)的针对不同场合的时变信道估计方法,并利用正交分解最小二乘(LSQR)对帧体进行均衡.第一种信道估计方法针对400Hz及以下多普勒频移,分别估计帧体前后帧头的一阶信道冲击响应,映射得到基展开系数,第二种方法针对400Hz以上情况,利用帧头循环结构,估计帧头内部信道的时变性,第三种方法针对945模式,对同一帧头进行两次一阶估计.由于信道矩阵使用基展开系数进行表示,因此LSQR均衡可以实现O(Nlog N)的复杂度.仿真结果显示,该方法提高了系统在高速时变下的性能.The application of the Chinese Digital Terrestrial Multimedia Broadcasting（DTMB） in highly mobile conditions is growing rapidly.Utilizing the time domain synchronous orthogonal frequency division multiplexing（TDS-OFDM） frame structure in its multicarrier mode,three channel estimation schemes based on basis expansion model（BEM） are proposed for applications under various conditions.Then a low complexity equalization method based on LSQR is presented.The first estimation method uses the channel impulse response（CIR） of the frame head before and after the frame body to build the BEM basis for Doppler shift which is less than 400Hz and for the 420transmission mode.The second method estimates explicitly the time variation of the frame head for Doppler shift which is larger than 400 Hz.The third method estimates the CIR of two time instances using the special structure of the frame head.This method is mainly designed for the 945mode.Since the CIR is represented using BEM,the LSQR equalizer achieves the complexity of O（Nlog N）.Simulation results show that the proposed approaches effectively improve the performance of multicarrier DTMB under high mobility.

关 键 词：信道估计 均衡 数字电视 时域同步正交频分复用 快时变 

分 类 号：TM934.3[电气工程—电力电子与电力传动]