基于导频ICI自消除的OFDM系统时变信道估计

Time-varying channel estimation in OFDM systems based on ICI self-cancellation of pilots

在基于分段线性模型的正交频分复用(orthogonal frequency division multiplexing,OFDM)时变信道估计中,存在模型参数估计精度受到载波间干扰(inter-carrier interference,ICI)影响的问题。为此,本文采用ICI自消除技术,抑制了导频子载波的ICI,改善了模型参数的估计性能。此外,还推导了单抽头Jakes信道条件下模型参数估计均方误差的表达式,理论分析表明,与基本的分段线性模型方法相比,本文方法可以使均方误差下降约13dB。仿真结果验证了在多抽头信道和大的多普勒扩展条件下,本文方法也能明显提高ICI抑制能力,从而得到更好的系统误码性能。

For time-varying channel estimation in orthogonal frequency division multiplexing （OFDM）sys-tems,the estimation accuracy of parameters of the piece-wise linear model is affected by inter-carrier interfer-ence （ICI）.In view of this point,the ICI self-cancellation technique is utilized to mitigate the ICI at pilot subcar-riers,resulting in improvement of the estimation performance.Meanwhile,the expression of the mean square error of model parameter estimation for the single-tap Jakes’channel is derived.Theoretical analysis demon-strates that the mean square error of parameter estimation obtained by the proposed method approximately de-creases 13 dB comparing with that by the basic piece-wise linear model approach.Numerical simulation results show that the proposed algorithm can also obviously improve the performance of ICI suppression in the case of multi-tap channel and large Doppler spread,leading to better system error performance.