小样本图像处理方法赋能的宽带频谱感知

针对强噪声环境下频谱感知方法计算复杂度高、难以获取大量标注样本、检测准确率低等问题，该文提出由图像去噪和图像分类思想驱动的频谱感知方法(IDCSS)。首先，对感知用户的接收信号进行时频变换，将无线电数值信号转换为图像。强噪声环境下感知用户接收信号图像与噪声图像相关度高，因此搭建生成对抗网络(GAN)来增加低信噪比下接收信号样本的数量，提高图像的质量。在生成器中，利用残差-长短时记忆网络取代生成网络U-Net结构中的跳跃连接，对图像进行去噪、提取感知用户接收信号图像的多尺度特征、建立基于熵的损失函数来构建网络的抗噪能力；在判决器中，设计适用无线电图像信号的多维度判决器来增强生成图像的质量、保留低信噪比感知用户信号的图像细节。最后利用分类器识别频谱占用状态。仿真结果表明，与现有频谱感知算法相比，所提算法具有较好的检测性能。

Image Processing-Driven Spectrum Sensing with Small Training Samples

To resolve the problems of high computational complexity in strong noise environment, infeasibility of gaining large number of labeled samples and low detection probability, an Image Denoising and Classification driven Spectrum Sensing (IDCSS) method is proposed. Firstly, time-frequency transformation is employed to convert radio numerical signals into images. Then, as received signals of cognitive users and noise are highly correlated under strong noise environments, a novel Generative Adversarial Network (GAN) is designed to enhance the number and quality of samples of cognitive user signals. In the generator, residual-long-short-term memory network is designed to replace U-Net skip connection, realizing denoising and multi-scale features extraction. Loss function based on entropy is designed to optimize robustness to noise. A multi-dimensional discriminator is designed to enhance the quality of the generated image and retain the image details of the low signal-to-noise ratio cognitive user signals. Finally, the generated high-quality samples are used as labeled data, and the real samples combine to train the classifier to realize the recognition and classification of the spectrum occupancy state. Simulation results show that the proposed algorithm has better detection performance by comparing it with the state-of-the-art methods.