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In this article, a high-security three-dimensional (3D) probabilistic shaping optical transmission system based on prefixfree code distribution matching (PCDM) and Polar code joint coding is proposed. The bit error rate (BER) performance of the communication system is optimized by using the probabilistic shaping effect of PCDM and the strong correction performance of Polar code. Meantime the Logistic and Lorenz chaotic models are used to mask the constellation map for multiple times to ensure the security transmission of data. The experiment verifies the transmission of 28.64Gb/s encrypted PCDM encoded signals on 2km 7-core fiber. At a BER is 1×10 -3 , the encrypted PCDM encoded signals improve the BER performance about 3dB compared to the conventional unencrypted 3D 32QAM signals. In terms of security performance, the key space of the proposed encryption scheme is up to 10 119 , and the BER of the illegal receiver is more than 0.4. The experimental results show that the proposed chaotic optical transmission scheme based on the joint encoding of PCDM and Polar can effectively improve the BER and security performance, which is a promising optical communication transmission scheme.

Unmanned aerial vehicles (UAVs), relying on wireless communication, are inevitably influenced by the complex electromagnetic environment, attributed to the development of wireless communication technology. The modulation information of signals can assist in identifying device information and interference in the environment, which is significant for UAV communication environment monitoring. Therefore, in scenarios involving the communication of UAVs, it is necessary to find out how to perform the spectrum monitoring method to obtain the modulation information. Most existing methods are unsuitable for scenarios where multiple signals appear in the same spectrum sequence or do not use an end-to-end structure. Firstly, we established a spectrum dataset to simulate the UAV communication environment and developed a label method. Then, detection networks were employed to extract the presence and location information of signals in the spectrum. Finally, decision-level fusion was used to combine the output results of multiple nodes. Five modulation types, including ASK, FSK, 16QAM, DSB-SC, and SSB, were used to simulate different signal sources in the communication environment. Accuracy, recall, and F1 score were used as evaluation metrics. The networks were tested at different signal-to-noise ratios (SNRs). Among the different modulation types, FSK exhibits the most stable recognition performance across different models. The proposed method is of great significance for wireless radio spectrum monitoring in complex electromagnetic environments and is adaptable to scenarios where multiple receivers are used in vast terrains, providing a deep learning-based approach to radio monitoring solutions for UAV communication.