DTMB系统在单频网信道下的信道估计

Channel Estimation in SFN Channel for DTMB

针对单频网信道的特点,提出了一种DTMB系统信道估计方法。该方法对基于PN的循环相关信道估计算法加以改进,在旁瓣干扰消除后,保留第一径的时域冲激响应,并消除第一径对帧头的影响,重新确定循环相关窗口,重复以上步骤,依次估计出整个信道的时域冲激响应,之后进行帧体循环重构与频域均衡来完成数据恢复的工作。该方法可以提高系统抑制长时延和强能量回波的能力。仿真结果表明,该方法在单频网信道下可以提高系统的误比特率性能。

In the view of single frequency network （SFN） channel characteristics, a channel estimation method for DTMB is proposed in this paper. This method is improved by circular correlation using PN sequences channel estimation, after interference cancellation, the time domain channel impulse response （CIR） of the first path is reserved, then the influence of the first path in the frame header is eliminated, and circular correlation window is redefined. The steps above are repeated, and the entire time domain CIR is estimated successively. After frame circular reconstruction and frequency equalization, the data is recovered. The ability to suppress the long delay and strong echo is improved. The simulation results prove that the bit error rate （BER） performance is ameliorated in the SFN channel.