一种基于CNN的阵列非平行失准OAM模态识别方法

      A CNN-based method for non-parallel misaligned OAM modal recognition of arrays

      • 摘要: 针对轨道角动量(orbital angular momentum,OAM)通信中收发阵列非平行失准情况下的模态识别难题,提出了一种结合相位补偿及机器学习的模态识别方案。该方案首先基于等效原理利用空间相位差异,得到接收阵元的补偿加权相位,建立接收阵列等效模型,通过该等效机制以恢复因收发阵列未对齐而失真的涡旋相位波前;其次,将补偿后的相位和幅度数据整合为二通道数据集,用于训练卷积神经网络(convolutional neural network, CNN)模型;最后,用训练好的网络进行模态识别。文章还介绍了传统的幅值检测模态识别方法,并通过对仿真算例的对比分析,验证了所提识别方案的准确性和稳定性。仿真结果证实:所提相位补偿方法能有效恢复信号的涡旋相位波前,且具有低复杂度;在OAM索引编码调制下,所提模态识别方案相较于传统方法,在误码率性能上实现了显著提升,并展现出优越的鲁棒性。本文方案以低复杂度、高准确性和高稳定性为特点,为OAM短距离高速通信在收发阵列非平行失准场景下提供了一种高效的模态接收识别解决方案。

         

        Abstract: In this paper, a modal identification method combining phase compensation and machine learning is proposed for the modal identification challenge in the case of non-parallel misalignment of transceiver arrays in orbital angular momentum (OAM) communication. Firstly, the method is based on the equivalence principle to utilize the spatial phase difference to obtain the compensated weighted phase of the receiving array elements and establish the receiving array equivalent model, through which the equivalence mechanism is used to recover the vortex phase wavefront distorted due to the non-alignment of the transceiver arrays. And secondly, the compensated phase and amplitude data are integrated into a two-channel dataset, which is used for the training of a convolutional neural network (CNN) model. Lastly, the modal identification is carried out using the trained network. The paper also describes the traditional modal identification method for amplitude detection (AD), and verifies the accuracy and stability of the proposed identification method through comparative analysis of simulation examples. The simulation results confirm that the proposed phase compensation method can effectively recover the vortex phase wavefront of the signal with the advantage of low complexity. Under OAM indexed coding modulation, the proposed modal recognition method achieves significant improvement in bit error rate (BER) performance and shows superior robustness compared with the traditional method. Characterized by low complexity, high accuracy and high stability, this method provides an efficient modal reception identification solution for OAM short-range high-speed communication in the transceiver array non-parallel misalignment scenario.

         

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