Degraded broadcast channels (DBC) are a typical multiuser communication
scenario, Semantic communications over DBC still lack in-depth research. In
this paper, we design a semantic communications approach based on multi-user
semantic fusion for wireless image transmission over DBC. In the proposed
method, the transmitter extracts semantic features for two users separately. It
then effectively fuses these semantic features for broadcasting by leveraging
semantic similarity. Unlike traditional allocation of time, power, or
bandwidth, the semantic fusion scheme can dynamically control the weight of the
semantic features of the two users to balance the performance between the two
users. Considering the different channel state information (CSI) of both users
over DBC, a DBC-Aware method is developed that embeds the CSI of both users
into the joint source-channel coding encoder and fusion module to adapt to the
channel. Experimental results show that the proposed system outperforms the
traditional broadcasting schemes.

我们设计了一种基于多用户语义融合的语义通信方法，用于在退化广播信道上进行无线图像传输。与传统的时间、功率或带宽分配不同，语义融合方案可以动态控制两个用户的语义特征权重，以平衡两者之间的性能。实验结果表明，所提出的系统优于传统的广播方案。