Compressive Sensing Based High-Resolution Channel Estimation for OFDM System
Compressive Sensing Based High-Resolution Channel Estimation for OFDM System
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DOI：
10.1109/jstsp.2011.2169649
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发表时间：
2012-02-01
影响因子：
7.5
通讯作者：
Han, Zhu
中科院分区：
文献类型：
--
作者：
Meng, Jia (Jasmine);Yin, Wotao;Han, Zhu
正交频分复用（OFDM）是下一代无线通信中的主流技术。信道估计是OFDM系统的关键技术之一，高精度的信道估计可以显著改善接收端的均衡性能，从而提高通信性能。在本文中，我们提出了一个系统与非对称的数模转换器/模数转换器（DAC/ADC）对和制定OFDM信道估计作为一个压缩感知问题。该系统通过巧妙地设计导频，利用信道冲激响应的稀疏性，以较低的代价实现了高分辨率的信道估计。导频设计、高速DAC和常规速度ADC的使用以及为信道估计量身定制的估计算法将所提出的方法与现有的估计方法区分开来。我们从理论上表明，在所提出的系统中，N分辨率的通道可以忠实地获得与ADC的速度在M = O（S-2 log（N/S）），其中N也是DAC的速度，是信道脉冲响应稀疏。由于S很小，并且将DAC速度提高到N > M相对便宜，因此我们可以以较低的成本获得高分辨率通道。我们还提出了一种新的估计，这是更快，更准确的比典型的l（1）最小化。在数值实验中，我们模拟了不同数量的多径和不同的SNR，并让发射机DAC以16倍于接收机ADC的速度运行，以16倍分辨率估计信道。虽然没有类似的方法（对于非对称DAC/ADC对）进行比较，但我们推导出Cramer-Rao下限。
Orthogonal frequency division multiplexing (OFDM) is a technique that will prevail in the next-generation wireless communication. Channel estimation is one of the key challenges in OFDM, since high-resolution channel estimation can significantly improve the equalization at the receiver and consequently enhance the communication performances. In this paper, we propose a system with an asymmetric digital-to-analog converter/analog-to-digital converter (DAC/ADC) pair and formulate OFDM channel estimation as a compressive sensing problem. By skillfully designing pilots and taking advantages of the sparsity of the channel impulse response, the proposed system realizes high-resolution channel estimation at a low cost. The pilot design, the use of a high-speed DAC and a regular-speed ADC, and the estimation algorithm tailored for channel estimation distinguish the proposed approach from the existing estimation approaches. We theoretically show that in the proposed system, a N-resolution channel can be faithfully obtained with an ADC speed at M = O(S-2 log(N/S)), where N is also the DAC speed and is the channel impulse response sparsity. Since S is small and increasing the DAC speed to N > M is relatively cheap, we obtain a high-resolution channel at a low cost. We also present a novel estimator that is both faster and more accurate than the typical l(1) minimization. In the numerical experiments, we simulated various numbers of multipaths and different SNRs and let the transmitter DAC run at 16 times the speed of the receiver ADC for estimating channels at the 16x resolution. While there is no similar approaches (for asymmetric DAC/ADC pairs) to compare with, we derive the Cramer-Rao lower bound.