移动正交频分复用接收机信道估计算法的研究

Channel estimation algorithm for mobile OFDM receivers

为了提高移动信道下正交频分复用(OFDM)接收机的性能,提出了一种适用于地面数字电视广播标准(DVB-T)的信道估计均衡算法.在对多普勒弥散引入的子载波间干扰(ICI)进行研究的基础上,根据OFDM符号间信道频率响应的变化量和内码模块译码输出值的二次卷积编码估计出ICI.给出了算法的实现结构及替代阈值的选取方法.通过分析及计算机定点仿真,确定了实现结构中的最优参数,并给出了典型城市信道6(TU6)下的移动接收性能曲线.结果表明,在信噪比为25dB时,和传统信道估计算法相比,增加了20Hz的多普勒移动性能.该算法提高了ICI估计的准确性,增强了DVB-T 8K系统的移动接收性能.

To improve the performance of orthogonal frequency division multiplexing （OFDM） receivers in the mobile channel, an algorithm for channel estimation and equalization suitable for digital video broadcast-terrestrial （DVB-T） was proposed. Based on the study of the inter carrier interference （ICI） introduced by the Doppler dispersion, the ICI was estimated by using the variations of the channel frequency response among the OFDM symbols and the convolutional re-encoding of the inner decoder＇s output. The realization structure and selection method of substitution thresholds were presented. The optimal parameters of the realization structure were determined by applying analysis and computer fixed point simulation, and the mobile reception performance curves under typical urban channel 6 （TU6） were presented. Simulation results show that compared with the conventional channel estimation algorithm, the increase in the Doppler mobile performance is 20 Hz when the signal to noise ratio is 25 dB. The algorithm improves the precision of ICI estimation and enhances the mobile reception performance of the DVB-T 8K system.