Analysis and mitigation of phase noise and sampling jitter in OFDM radio receivers
Analysis and mitigation of phase noise and sampling jitter in OFDM radio receivers
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OFDM 无线电接收机中相位噪声和采样抖动的分析和缓解
DOI：
10.1017/s1759078710000309
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发表时间：
2010
影响因子：
1.4
通讯作者：
M. Valkama
中科院分区：
文献类型：
--
作者：
V. Syrjala;M. Valkama
本文研究了基于数字信号处理(DSP)技术的正交频分复用(Ofdm)无线电系统中相位噪声和采样时钟抖动的分析和抑制方法。在相位噪声研究中，假设直接转换接收机的基本结构为带噪声的下变频振荡器。另一方面，在采样抖动的情况下，利用带通子采样原理部署了所谓的直接射频采样接收机结构。基于DSP的损伤抑制技术的基础首先是使用具有输入的ofdm波形的解析接收器建模来形成的，其中振荡器相位噪声和采样时钟抖动的影响被映射到与理想接收器情况相比的特定类型的子载波串扰和失真。然后，开发了迭代检测原理和内插技术来本质上估计和消除副载波失真。文中还讨论了相关的实用问题，如信道估计。通过大量的计算机仿真，分析和验证了所提出的抑制技术的性能。在仿真中，使用了基于实际锁相环的振荡器模型来研究相位噪声和采样时钟抖动。此外，还考虑了不同的接收信号条件，如平坦的加性高斯白噪声信道和扩展的ITU-R车载A多径信道。结果表明，利用所开发的信号处理技术，可以有效地减小振荡器和采样时钟不稳定的影响。
This article addresses the analysis and digital signal processing (DSP)-based mitigation of phase noise and sampling clock jitter in orthogonal frequency division multiplexing (OFDM) radios. In the phase noise studies, the basic direct-conversion receiver architecture case is assumed with noisy downconverting oscillator. In the sampling jitter case, on the other hand, the so-called direct-radio-frequency-sampling receiver architecture is deployed utilizing bandpass sub-sampling principle. The basis for the DSP-based impairment mitigation techniques is first formed using analytical receiver modeling with incoming OFDM waveform, where the effects of both oscillator phase noise and sampling clock jitter are mapped to certain type subcarrier cross-talk and distortion compared to ideal receiver case. Then iterative detection principles and interpolation techniques are developed to essentially estimate and cancel the subcarrier distortion. Also some related practical aspects, like channel estimation, are addressed. The performance of the proposed mitigation techniques is analyzed and verified with extensive computer simulations. In the simulations, realistic phase-locked-loop-based oscillator models are used for phase noise and sampling clock jitter. In addition, different received signal conditions like plain additive white Gaussian noise channel and extended ITU-R Vehicular A multipath channel are considered for practical purposes. Altogether the obtained results indicate that the effects of oscillator and sampling clock instabilities can be efficiently reduced using the developed signal processing techniques.