中文摘要：

高速移动下的无线宽带通信要经历时间和频率双选择性衰落，信道估计质量的好坏对整个系统的性能有重要的影响。该文利用复指数基扩展模型，提出一种基于最小二乘的时频双选信道估计方法，接收机不需要信道的统计信息，也不需要预先估计噪声方差，接收机复杂度较低；在该信道估计算法的基础上，基于信道估计均方误差最小准则，分析并推导出优化的训练序列所要满足的条件。仿真结果表明，在由Jakes’模型产生的时频双选衰落信道下，在一定的信噪比范围内，该文方法的信道均方误差性能优于现有的方法。

英文摘要：

High data rates and high mobility induced Doppler shifts introduce time and frequency selectivity in wireless links. The quality of channel acquisition has a major impact on the overall system performance. In this paper, relying on a basis expansion channel model, a scheme is proposed for estimating doubly selective channel parameters. The receiver does not have to know the statistic information of the channels and will not estimate the power of noise in advance, and has low-complexity. Along with the estimation scheme, the optimal pilot sequence is derived based on minimizing mean-square error of the channel estimation. Simulation results demonstrate the performance of the proposed scheme is better than existing scheme for a range of SNR, where a frequency- selective channel is randomly generated with different Doppler spreads via Jakes＇ model.