OFDM系统二维变换域信道估计算法

2-D Transform Domain Channel Estimation Method for OFDM Systems

着重分析OFDM系统的二维变换域(2-D transform-domain)的导频辅助信道估计。在变换域中对导频位置的信道频率响应(CFR)矩阵采用右下补零和中间补零两种方式进行插值,以获得整个信道的频率响应。考虑到上述两种方法带来的插值误差,提出了根据时间、频率方向的导频数目采用不同的补零数量和补零方式。采用Simulink构建基带仿真系统,仿真改进前后的系统误比特率(BER)并和其他二维插值方式进行比较。结果表明,该改进方法显著地提高了基于变换域信道估计的准确性,降低了系统的误比特率。

Pilot-symbol-assisted channel estimation techniques of 2-D transform-domain OFDM system. The right-bottom zero-padding and middle zero-padding of pilot-position channel frequency response （CFR） matrix are utilized to gain the whole channel＇s CFR. To decrease the interpolation error of aforementioned zero-padding methods, a novel method is proposed which uses different number zeros and different padding mode based on pilot quantity along frequency and time direction. Lastly, by Simulink baseband model, the proposed method is verified and compared with other 2-D interpolations. Results show that it can improve the channel estimation accuracy and decrease system bit error rate （BER） observably.