地空信道下基于OFDM/OQAM系统的信道估计研究*

针对地空信道时变快，正交频分复用/偏移正交幅度调制(OFDM/OQAM)系统存在固有干扰的问题，提出一种信道估计算法。该信道估计算法包含一种新型的梳状导频结构和一种改进的线性插值算法。提出的新型梳状导频通过将导频周围数据置零来消除系统的固有干扰和减小子载波间干扰对信道估计的影响，且导频分布在整个时间轴上，因而可以较好的跟踪信道状态；改进的线性插值算法通过在时域插零，来减小信道噪声和系统干扰对信道估计的影响。仿真结果表明，提出的梳状导频相比于传统梳状导频具有较好的优势，可有效提高系统的抗误码性能；改进的线性插值算法相比于传统插值算法可有效提高系统的可靠性。

Channel estimation algorithm for OFDM/OQAM system under the air-ground channel. Computer Engineering and Applications*

Since air-ground channel and orthogonal frequency division multiplexing/offset quadrature amplitude modulation (OFDM/OQAM) system has the fast time-varying characteristic and intrinsic interference characteristic respectively, this paper proposes a channel estimation algorithm. This channel estimation algorithm contains a novel comb-pilot and an improved linear interpolation algorithm. The novel comb-pilot can eliminate the intrinsic interference of the system and reduce the influence of the inter-carrier interference (ICI) on the channel estimation by zero-padding around the pilot, and the pilot is distributed over the whole time axis, so it can track the channel state better. And the improved linear interpolation algorithm can reduce the influence of channel noise and interference on channel estimation by zero-padding in the time domain. Simulation results show that the novel comb-pilot has better advantages compared to the conventional comb-pilot, which can effectively improve the bit error rate (BER) performance of the system, and the improved linear interpolation algorithm can effectively improve the reliability of the system compared to the traditional interpolation algorithm.