数字调幅广播系统中基于滑动窗口的二维信道估计

Two-dimensional channel estimation based on sliding window for digital amplitude modulation broadcasting system

针对DRM数字广播系统,提出一种基于滑动窗口的二维信道估计方法。该方法首先对接收到的导频信号所在信道进行最小二乘估计,然后进行时间方向插值估计导频子载波上所有位置处的信道频率响应,最后通过一个滑动窗口在多径扩展域和多谱勒扩展域分别进行处理。对于快速时变信道,通过调整窗口的滑动步数,可以有效处理窗口内信道路径数和路径延迟可能变化的情况,从而显著降低了子载波间干扰和高斯白噪声的影响。理论分析和仿真表明,与现有信道估计相比,该方法具有估计精确、易于实现的优点。

A novel two-dimensional channel estimation method based on sliding window is proposed for OFDM-based digital amplitude modulation broadcasting system. The method first makes least square channel estimation for received pilot signal; then interpolates in time direction to estimate the channel transfer function at the sub-carriers; at last, it processes the received pilots in both multi-path spread domain and Doppler spread domain. The method significantly reduces the influence of Inter-Carrier Interference （ICI） due to time-variant shortwave channel and additive white Gaussian noise （AWGN）. Additionally, it is robust in the sense that it can capture different path number and different path delay in a sliding window by an adjustable sliding step. Both theoretical analysis and simulation results demonstrate that the proposed method performs well at typical mid-wave and short-wave broadcasting channels and is easier to implement.