面向OFDM系统信道估计的空间信息增强小波域网络

    Spatial information enhanced wavelet domain network for channel estimation of OFDM systems

    • 摘要: 在5G无线网络的正交频分复用系统中,信道估计对于实现信号的精确恢复及可靠通信起着至关重要的作用。传统的信道估计方法存在速度慢、精确度低的缺陷。基于深度学习的方法虽能够解决该问题,但是现有基于深度神经网络的方法仍然存在以下不足:传统卷积神经网络方法因表示能力受限导致精度低;基于Transformer的信道估计方法虽能够取得较高的重建质量,却存在计算复杂度偏高、耗时较长以及参数量较多等问题。为了寻求计算复杂度、参数量和估计性能三者之间的平衡,本文提出了一种基于小波分解和双流网络的信道估计方法,旨在通过低分辨率的信道响应估计高分辨率的信道响应。为增强小波域网络的表示能力,通过引入空间特征提取模块,借助空域信息来辅助小波系数的估计。为实现空域信息和小波域网络特征的融合,设计了双分支网络,将获取的小波系数和空间特征分四组输入到双流网络中进行融合。仿真结果表明,提出的网络计算复杂度和参数量较低,能够实现高效且准确的信道估计。

       

      Abstract: In the orthogonal frequency division multiplexing system of the 5G wireless network, channel estimation plays an important role in realizing accurate signal recovery and reliable communication. The traditional channel estimation method has defects of slow speed and low accuracy. Although the technique based on deep learning can solve this problem, the existing method based on deep neural networks still has the following shortcomings: the traditional convolutional neural network method has low accuracy due to its limited representation capability; although the channel estimation method based on Transformer can achieve high reconstruction quality, it has some problems such as high computational complexity, long time consumption and large number of parameters. To seek a balance among computational complexity, the number of parameters, and estimation performance, a channel estimation method based on wavelet decomposition and dual-stream network is proposed in this paper, aiming to estimate high-resolution channel responses from low-resolution channel responses. To enhance the representation ability of wavelet domain network, a spatial feature extraction module is introduced to assist the estimation of wavelet coefficients with the help of spatial information. In order to achieve the fusion of spatial information and wavelet domain network features, a two-branch network is designed. The obtained wavelet coefficients and spatial features are input into the dual-stream network in four groups for fusion. Simulation results show that the proposed network has low computational complexity and parameters, and can achieve efficient and accurate channel estimation.

       

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