SCDM: Score-Based Channel Denoising Model for Digital Semantic Communications

TL;DR

This paper introduces SCDM, a score-based denoising model tailored for digital semantic communications, which improves robustness and efficiency in noisy channels by aligning diffusion noise with digital channel noise characteristics.

Contribution

The paper proposes a novel score-based diffusion approach specifically designed for digital semantic communication noise, enhancing denoising performance and reducing storage needs.

Findings

Outperforms baseline in PSNR, SSIM, MSE metrics at low SNR

Reduces storage requirements by a factor of 7.8

Enhances robustness of semantic information extraction

Abstract

Score-based diffusion models represent a significant variant within the diffusion model family and have seen extensive application in the increasingly popular domain of generative tasks. Recent investigations have explored the denoising potential of diffusion models in semantic communications. However, in previous paradigms, noise distortion in the diffusion process does not match precisely with digital channel noise characteristics. In this work, we introduce the Score-Based Channel Denoising Model (SCDM) for Digital Semantic Communications (DSC). SCDM views the distortion of constellation symbol sequences in digital transmission as a score-based forward diffusion process. We design a tailored forward noise corruption to align digital channel noise properties in the training phase. During the inference stage, the well-trained SCDM can effectively denoise received semantic symbols under various SNR conditions, reducing the difficulty for the semantic decoder in extracting semantic information from the received noisy symbols and thereby enhancing the robustness of the reconstructed semantic information. Experimental results show that SCDM outperforms the baseline model in PSNR, SSIM, and MSE metrics, particularly at low SNR levels. Moreover, SCDM reduces storage requirements by a factor of 7.8. This efficiency in storage, combined with its robust denoising capability, makes SCDM a practical solution for DSC across diverse channel conditions.