基于深度学习的分布式异构频谱感知

Deep learning-enabled distributed heterogeneous spectrum sensing

  • 摘要: 随着移动互联网的快速发展,移动设备的数量急剧增加,导致频谱资源日趋紧张。动态频谱分配是缓解频谱资源紧张的有效途径。动态频谱分配依赖于频谱感知,即探测出未被占用的频段。传统的频谱感知通常只考虑单个感知节点的情景,监控范围较小。为了监控较大的地理范围,须考虑多个节点联合感知的架构,即分布式频谱感知。由于模数转换器硬件精度不同、感知环境的复杂程度不同等因素,分布式系统中广泛存在着设备间的异构性。为了解决该问题,本文提出一种新的分布式频谱感知架构。所提出的架构包含若干个感知节点,每个节点上部署一个卷积神经网络,用于鉴别所监控的频谱是否处于被占用状态。该分布式架构要求不同节点的浅层网络共享权值参数,而深层网络的参数在节点之间是独立的。这一设计的动机源于浅层网络的特征提取受信噪比影响较小,因而不同节点共享浅层网络的权值可以提高样本利用率。其次,深层网络参数受信噪比影响较大,为了提高感知系统对本地信噪比的鲁棒性,每个节点应仅使用各自的训练样本来训练其深层网络。仿真标明,所提出的方法能够显著提高异构感知网络的检测准确性。

     

    Abstract: With the rapid development of mobile internet, the number of mobile devices has sharply increased, leading to a shortage of spectrum resources. Dynamic spectrum allocation is an effective way to alleviate the shortage of spectrum resources. Dynamic spectrum allocation relies on spectrum sensing, which detects unoccupied frequency bands. Traditional spectrum sensing methods only consider the scenario of a single sensing node, which can only monitor a limited geographical scope. In order to monitor a large geographical range, it is necessary to consider the joint sensing architecture, namely, distributed spectrum sensing architecture. Due to the varying hardware accuracy and sensing environment, there exists heterogeneity among devices in a distributed system. To address this issue, this paper proposes a new distributed spectrum sensing architecture. The proposed architecture consists of several sensing nodes, each equipped with a convolutional neural network (CNN) to identify whether the spectrum is occupied. The proposed distributed architecture requires shallow layers of different nodes to share weight parameters, while the parameters of the deep layers remain independent across nodes. The motivation stems from the fact that feature extraction in shallow layers is less affected by signal-to-noise ratio (SNR), thus sharing the weights of shallow layers among different nodes can improve sample efficiency. The parameters of the deep layers are more significantly affected by the SNR. To enhance the robustness of the perceptual system to the local SNR, each node should train its deep layers using only its own training samples. The proposed method can significantly improve the detection accuracy of heterogeneous sensing networks.

     

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