Transformer-Aided Wireless Image Transmission With Channel Feedback

This paper presents a novel wireless image transmission paradigm that can exploit feedback from the receiver, called JSCCformer-f. We consider a block feedback channel model, where the transmitter receives noiseless/noisy channel output feedback after each block. The proposed scheme employs a single encoder to facilitate transmission over multiple blocks, refining the receiver’s estimation at each block. Specifically, the unified encoder of JSCCformer-f can leverage the semantic information from the source image, and acquire channel state information and the decoder’s current belief about the source image from the feedback signal to generate coded symbols at each block. Numerical experiments show that our JSCCformer-f scheme achieves state-of-the-art performance with robustness to noise in the feedback link. Additionally, JSCCformer-f can adapt to the channel condition directly through feedback without the need for separate channel estimation. We further extend the scope of the JSCCformer-f approach to include the broadcast channel, which enables the transmitter to generate broadcast codes in accordance with signal semantics and channel feedback from individual receivers.