Conventional orthogonal matching pursuit (OMP) based channel estimation adopts discretized grids to represent path delays, which leads to energy leakage of off-grid paths. From the perspective of linear fitting, utilizing multiple atoms with fractional delays and shortening the distance between these atoms in the off-grid path reconstruction can reduce the energy leakage. To this end, an improved OMP channel estimation scheme is proposed in this letter for higher estimation accuracy. The proposed scheme utilizes trigonometric function based interpolation twice to estimate the delays of two atoms, which are adopted to reconstruct an off-grid path. Furthermore, a two-step search strategy is introduced to keep low computational complexity. The advantage of the proposed scheme is validated in simulations.

中文翻译：

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OFDM 系统中基于双插值的线性拟合 OMP 信道估计


传统的基于正交匹配追踪（OMP）的信道估计采用离散网格来表示路径延迟，这导致离网路径的能量泄漏。从线性拟合的角度来看，在离网路径重构中利用具有分数延迟的多个原子并缩短这些原子之间的距离可以减少能量泄漏。为此，本文提出了一种改进的OMP信道估计方案，以获得更高的估计精度。该方案利用基于三角函数的插值两次来估计两个原子的延迟，并用于重建离网路径。此外，引入了两步搜索策略以保持较低的计算复杂度。所提出方案的优点在仿真中得到验证。