Similar to orthogonal frequency division multiplexing receiver, the frequency-domain (FD) channel estimation (CE) and equalization are indispensable parts in the coherent single carrier frequency division multiplexing (SC-FDM) receiver. When the channel varies slowly, the FD processing is cost effective. For the applications with high mobility, the traditional implementation of the SC-FDM receiver causes significant performance degradation. In this paper, we propose to estimate time-varying pieces of channel taps for pilot symbols based on basis expansion model (BEM), and subsequently to reconstruct time-domain (TD) channel response for data symbols by utilizing the Slepian sequences-based piece-wise interpolation. Furthermore, two simplified schemes, i.e., the Slepian sequences-based multiple-point interpolation and the segmented BEM, are developed to reduce the computational complexity of the TD-CE. The Cramer-Rao lower bound (CRLB) of channel impulse response (CIR) estimation is also analyzed. In the light of the sparsity of TD channel gain matrix, we design an iterative least-squares QR decomposition algorithm to equalize the SC-FDM symbols. In the simulated SC-FDM system, when considering the carrier frequency of 5.9 GHz and the velocity of about 510 km/h, we observe that the traditional FD methods cause the demodulation failure, while the proposed TD processing schemes achieve ideal error-probability performance and preserve a relatively low complexity.

中文翻译：

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SC-FDM 系统信道估计和均衡的时域方法

与正交频分复用接收机类似，频域（FD）信道估计（CE）和均衡是相干单载波频分复用（SC-FDM）接收机中必不可少的部分。当通道变化缓慢时，FD 处理具有成本效益。对于具有高移动性的应用，SC-FDM 接收器的传统实现会导致显着的性能下降。在本文中，我们建议基于基扩展模型 (BEM) 估计导频符号的时变信道抽头，然后利用基于 Slepian 序列的片段重建数据符号的时域 (TD) 信道响应明智的插值。此外，两种简化方案，即基于 Slepian 序列的多点插值和分段 BEM，开发用于降低 TD-CE 的计算复杂度。还分析了信道脉冲响应 (CIR) 估计的 Cramer-Rao 下界 (CRLB)。针对TD信道增益矩阵的稀疏性，我们设计了一种迭代最小二乘QR分解算法来均衡SC-FDM符号。在模拟的 SC-FDM 系统中，当考虑 5.9 GHz 的载频和约 510 km/h 的速度时，我们观察到传统的 FD 方法导致解调失败，而提出的 TD 处理方案实现了理想的错误概率性能并保持相对较低的复杂性。我们设计了一种迭代最小二乘 QR 分解算法来均衡 SC-FDM 符号。在模拟的 SC-FDM 系统中，当考虑 5.9 GHz 的载频和约 510 km/h 的速度时，我们观察到传统的 FD 方法导致解调失败，而提出的 TD 处理方案实现了理想的错误概率性能并保持相对较低的复杂性。我们设计了一种迭代最小二乘 QR 分解算法来均衡 SC-FDM 符号。在模拟的 SC-FDM 系统中，当考虑 5.9 GHz 的载频和约 510 km/h 的速度时，我们观察到传统的 FD 方法导致解调失败，而提出的 TD 处理方案实现了理想的错误概率性能并保持相对较低的复杂性。