一种新的连续导频信道估计方法在LAS-CDMA系统中的应用  

A New Channel Estimation Method Based on Continuous Pilot Channel with Regression in LAS-CDMA

作　　者：王刚[1] 李永会[1] 董江波[1] 李道本[1] 

机构地区：[1]北京邮电大学,北京100876

出　　处：《电子学报》2005年第7期1247-1249,共3页Acta Electronica Sinica

基　　金：国家自然科学基金(No.69931050)

摘　　要：在下行链路中,通常用连续导频方法来进行信道估计.相比传统CDMA系统,LAS-CDMA系统中的LS扩频码具有理想的自相关特性和存在零相关窗(IFW:interferencefreewindow)的互相关特性.因此,当用连续导频方法进行信道估计时,估计的误差主要是由噪声引起的.为了抑制噪声的影响,本文提出了一种结合回归(regression)算法的新连续导频信道估计方法.在ITU-VA信道模型下,我们仿真了不同车速时采用新型信道估计方法的LAS-CDMA系统的BER(biterrorrate)性能.仿真结果表明,这种新方法由于提高了信道估计的准确度从而大大改善了系统的性能.For downlink transmission, known pilot symbols are usually used to evaluate the channel characters through the common pilot channel. Comparing to traditional CDMA, LS spreading codes in LAS-CDMA （Large Area Code Division Multiple Access） have IFW （ Interference Free Window ）. Thus when pilot symbols are used, AWGN （ Additive White Gaussian Noise） is the main obstacle to the accuracy.To suppress the noise degradation,in this paper,a new channel estimation method for LAS-CDMA system is intro- ducod. In the proposed method, the channel cnefficients obtained through common pilot channel are first fed to a regression process and these updated cnefficients are then for the corresponding data symbol recovery. Linear and nonlinear regression schemes are both considered according to vehicle speeds and regression process lengths over the ITU-VA channel. Simulation results prove that this method can improve the channel estimation accuracy and system BER （Bit Error Rate）performance greatly.

关 键 词：LAS-CDNA 信道估计 线性回归 非线性回归 

分 类 号：TN911[电子电信—通信与信息系统]