Eigendecomposition-Based Partial FFT Demodulation for Differential OFDM in Underwater Acoustic Communications
Eigendecomposition-Based Partial FFT Demodulation for Differential OFDM in Underwater Acoustic Communications
复制标题
水声通信中差分 OFDM 的基于特征分解的部分 FFT 解调
DOI：
10.1109/tvt.2018.2813327
复制
发表时间：
2018-07-01
影响因子：
6.8
通讯作者：
Leus, Geert
中科院分区：
文献类型：
--
作者：
Han, Jing;Zhang, Lingling;Leus, Geert
差分正交频分复用（OFDM）技术在水声通信中具有很好的应用前景。然而，类似于相干OFDM，它可能遭受严重的载波间干扰在时变信道上。为了减轻所引起的性能下降，我们采用了新出现的部分快速傅里叶变换（FFT）解调技术在本文中，并提出了一种基于特征分解的算法来计算合并权重。与现有的自适应方法相比，新算法可以避免误差传播，并消除了参数调整的需要。此外，它保证了在窄带多普勒假设下的全局最优性，与部分FFT解调的最佳权向量的导频检测误差矩阵的最小特征值相关联的特征向量实现。最后，该算法还可以直接扩展到执行子带计算，以抵消宽带多普勒效应。
Differential orthogonal frequency division multiplexing (OFDM) is practically attractive for underwater acoustic communications since it has the potential to obviate channel estimation. However, similar to coherent OFDM, it may suffer from severe inter-carrier interference over time-varying channels. To alleviate the induced performance degradation, we adopt the newly emerging partial fast Fourier transform (FFT) demodulation technique in this paper and propose an eigendecomposition-based algorithm to compute the combining weights. Compared to existing adaptive methods, the new algorithm can avoid error propagation and eliminate the need for parameter tuning. Moreover, it guarantees global optimality under the narrowband Doppler assumption, with the optimal weight vector of partial FFT demodulation achieved by the eigenvector associated with the smallest eigenvalue of the pilot detection error matrix. Finally, the algorithm can also be extended straightforwardly to perform subband-wise computation to counteract wideband Doppler effects.