OFDM通信系统中的一种通用的信道估计模型

A General Channel Estimation Model for OFDM System

本文根据DFT的一个性质为OFDM通信系统构造了一种通用信道估计模型。 该模型利用系统子信道中的一部分专门进行信道估计,适用于慢消失信道。该模型同最小平方差(LS)和最小均方差(LMMSE)相结合分别形成两种信道估计方法, 并从理论角度分别分析它们的计算复杂性和均方差性能。对多径信道仿真表明,基于LS的方法误符号率性能比基于LMMSE的方法差2-3dB,但是计算复杂度较低。总之,此信道估计模型的计算复杂度和性能随着用于信道估计的子信道数目增加而增加，当所用子信道数目是周期头长度的两倍时,达到计算量和估计性能的最佳平衡。

A general channel estimate model for OFDM system is proposed. This model, which is also called LMMSE channel estimator (LMMSECE) if it is combined with LMMSE, selects M sub-channels from the total N sub-channels to estimate the channel attenuation and is suitable for slow fading multi-path channels with good performance but medium computing complexity. When combined with LS , this model is called LS channel estimator (LSCE). In this case, Its computing complexity is low, but its performance is poorer than LMMSECE. Computer simulations regarding uncoded SER are conducted both for LSCE and LMMSECE in multipath channel environment. Simulation result shows that computing complexity and performance of the model increase with the value of M. When M=2L, the model achieves the optimal tradeoff between the two.