基于EM算法的改进OFDM时变信道估计

针对正交频分复用（OFDM）系统中的信道时变,基于时变信道的分段线性近似模型,提出一种改进的OFDM时变信道估计方案。该方案通过采用期望最大化（EM）迭代算法来提高符号平均信道脉冲响应的估计精度,从而提高时变信道估计的性能;此外,在迭代过程中进行带状子载波间干扰抑制,不仅进一步提高了时变信道估计的性能,而且降低了实现复杂度。理论分析和仿真结果表明,该算法以较低的复杂度代价有效提高了时变信道OFDM系统的性能。

Modified Time-Varying Channel Estimation for OFDM Based on EM Algorithm

For the channel time variations in orthogonal frequency division multiplexing(OFDM) systems,a modified channel estimation scheme for OFDM systems based on the piece-wise linear approximation of time-varying channels is proposed.The proposed scheme,with expectation maximization(EM) algorithm,could improve the estimation accuracy for average channel impulse responses of the symbol,thus improving the estimation performance of time-varying channels.In addition,the banded intercarrier interference mitigation scheme in iterations could further raise the channel estimation performance and reduce the implementation complexity.Theoretical analysis and simulation results show that the proposed scheme could significantly improve the system performance in time-varying scenarios and maintain the low complexity as well.