一种改进的DVB-T信道估计算法

An Improved Channel Estimation Method for DVB-T System

针对传统DVB-T系统信道估计算法估计精度低或复杂度高的问题,为了提高信道估计算法整体性能,提出了一种改进的DVB-T信道估计算法;该算法首先采用最小二乘法估计离散导频处频率响应估计值;进而,利用连续导频对信噪比进行估计;最后,将得到的信噪比估计值与预先设定的信噪比阈值进行比较,若估计值小于阈值,则先经过卡尔曼滤波处理,再在时频二维方向上用高斯插值得到全部子载波的频率响应值,否则直接在时域和频域上进行插值;此方法在信道条件较好时关闭卡尔曼滤波过程,从而有效减少滤波次数,提高算法整体运行速度;仿真结果表明,该方法能有效提高系统整体性能,减少在噪声影响较大时的干扰,同时也兼顾了算法整体运行速度。

For the problem that poor performance or high complexity of the traditional DVB-T system channel estimation algorithm,in order to improve the overall performance of channel estimation algorithm,an improved DVB-T channel estimation method is proposed in this paper.Firstly,using the least squares to estimate frequency response value of scattered pilots;then,using continuous pilot to estimate the signal-to-noise ratio;Finally,compared with the preset threshold,if the estimated Signal-Noise ratio is smaller,firstly through Kalman filtering,then using Gaussian interpolation in time-frequency direction to get all frequency response values,or interpolating directly in the time domain and the frequency domain.This method close the Kalman filtering process when the channel condition is good,thus effectively reducing frequency of filter and improving the overall algorithm.The simulation results show that on the maintain of the operation speed,the proposed method can improve the performance of the system and reduce the interference when the noise is large.