MIMO OFDM系统时变信道估计及最优导频分布

Time-Varying Channel Estimation and Pilot Tone Placement for MIMO OFDM Systems

基于分段线性模型,提出了一种利用导频序列的信道估计算法.该算法首先利用导频序列估计出当前OFDM符号间隔内信道线性变化的斜率和中间时刻信道的冲激响应值,然后根据线性模型利用估计出的参数得到当前符号间隔内所有时刻上的信道冲激响应.此外,还研究了所提算法中的导频分布问题.可以证明,在快时变环境下,分组且每组等间隔分布于频域上的导频序列有着更好的系统性能.仿真结果表明了所提算法在时变环境下的有效性和采用等间隔分组导频序列的优越性.

Time-varying channel estimation for MIMO OFDM systems is challenging. Based on piecewise linear model, this paper proposes an estimation method that first estimates the slope of linear variant and the channel impulse response at the middle time of the current OFDM symbol using pilot sequences, and then estimates the whole channel impulse response through the estimated parameters. Along with the estimation scheme, pilot tone placement is studied. It is better to group pilot tones together into clumps that are equispaced in the frequency domain. Simulation results show effectiveness of the proposed scheme and demonstrate superiority of using the equispaced-grouped pilot sequences.