S-MDMA: Sensitivity-Aware Model Division Multiple Access for Satellite-Ground Semantic Communication
Hui Cao, Rui Meng, Shujun Han, Song Gao, Xiaodong Xu, Ping Zhang
TL;DR
This work tackles bandwidth-limited satellite-ground SemCom by proposing S-MDMA, a sensitivity-aware model division multiple access framework. It decomposes semantic features into shared and differential parts, ranks features by reconstruction sensitivity, and uses a Kronecker-based orthogonal embedding to enable interference-free multi-user transmission. A lightweight geometric-mean reconstruction loss ensures balanced performance across users with varying SNRs, and a bandwidth-pruning step preserves only the most informative features under constrained channels. Experiments on DLRS and NWPU VHR-10 demonstrate that S-MDMA consistently outperforms Deep JSCC, WITT, and MDMA in PSNR and SSIM across diverse SNRs and datasets, with ablation results confirming the value of the sensitivity sorting and orthogonal embedding components. The approach offers a scalable, on-board friendly solution for robust, high-fidelity satellite-ground SemCom in real-world settings.
Abstract
Satellite-ground semantic communication (SemCom) is expected to play a pivotal role in convergence of communication and AI (ComAI), particularly in enabling intelligent and efficient multi-user data transmission. However, the inherent bandwidth constraints and user interference in satellite-ground systems pose significant challenges to semantic fidelity and transmission robustness. To address these issues, we propose a sensitivity-aware model division multiple access (S-MDMA) framework tailored for bandwidth-limited multi-user scenarios. The proposed framework first performs semantic extraction and merging based on the MDMA architecture to consolidate redundant information. To further improve transmission efficiency, a semantic sensitivity sorting algorithm is presented, which can selectively retain key semantic features. In addition, to mitigate inter-user interference, the framework incorporates orthogonal embedding of semantic features and introduces a multi-user reconstruction loss function to guide joint optimization. Experimental results on open-source datasets demonstrate that S-MDMA consistently outperforms existing methods, achieving robust and high-fidelity reconstruction across diverse signal-to-noise ratio (SNR) conditions and user configurations.
