Wireless Image Transmission With Semantic and Security Awareness

Semantic communication is an increasingly popular framework for wireless image transmission due to its high communication efficiency. With the aid of the joint-source-and-channel (JSC) encoder implemented by neural network, semantic communication directly maps original images into symbol sequences containing semantic information. Compared with the traditional separate source and channel coding design used in bit-level communication systems, semantic communication systems are known to be more efficient and accurate especially in the low signal-to-the-noise ratio (SNR) regime. This thus prompts a critical while yet to be tackled issue of security in semantic communication: it makes the eavesdropper much easier to crack the semantic information as it can be retrieved even in a highly noisy channel. In this letter, we develop a semantic communication framework that accounts for both semantic meaning decoding efficiency and its risk of privacy leakage. To this end, targeting wireless image transmission, we propose an JSC autoencoder featuring residual structure for efficient semantic meaning extraction and transmission, and the training of which is guided by a well-designed loss function that can flexibly regulate the efficiency-privacy trade-off. Extensive experimental results are provided to show the effectiveness and robustness of the proposed scheme.