Multi-user Wireless Image Semantic Transmission over MIMO Multiple Access Channels
Bingyan Xie, Yongpeng Wu, Feng Shu, Jiangzhou Wang, Wenjun Zhang
TL;DR
The paper tackles uplink semantic image transmission over a two-user MIMO-MAC by introducing MU-LCFSC, a CSI-aware framework that fuses channel state information into both semantic encoders and decoders and uses a cooperative SIC-based decoder with a CVAE-inspired mask-ratio generator. Its core contributions include a cooperative semantic decoder with a learnable mask ratio, and a CVAE-based mechanism (CMRG) to adapt attention masks for inter-user interference mitigation. Empirical results on the UDIS-D dataset show MU-LCFSC achieving about $3$ dB PSNR gains over DeepJSCC-NOMA under comparable conditions, with robust performance across varying SNRs and CBRs and improved visual quality. The approach promises enhanced robustness and spectral efficiency for multi-user semantic communications in 6G uplink scenarios, by jointly optimizing semantic encoding/decoding and interference cancellation under MIMO fading.
Abstract
This paper focuses on a typical uplink transmission scenario over multiple-input multiple-output multiple access channel (MIMO-MAC) and thus propose a multi-user learnable CSI fusion semantic communication (MU-LCFSC) framework. It incorporates CSI as the side information into both the semantic encoders and decoders to generate a proper feature mask map in order to produce a more robust attention weight distribution. Especially for the decoding end, a cooperative successive interference cancellation procedure is conducted along with a cooperative mask ratio generator, which flexibly controls the mask elements of feature mask maps. Numerical results verify the superiority of proposed MU-LCFSC compared to DeepJSCC-NOMA over 3 dB in terms of PSNR.
