Blind MIMO Semantic Communication via Parallel Variational Diffusion: A Completely Pilot-Free Approach

TL;DR

This paper introduces Blind-MIMOSC, a fully pilot-free MIMO semantic communication framework that uses a diffusion-based blind receiver with pre-trained score networks for joint channel estimation and source recovery, outperforming existing methods.

Contribution

It presents the first fully pilot-free joint channel estimation and source recovery method for MIMO systems using a diffusion-based approach with pre-trained score networks.

Findings

Achieves superior recovery accuracy compared to state-of-the-art methods.

Reduces channel bandwidth ratio significantly.

Operates without any pilot signals, simplifying system design.

Abstract

In this paper, we propose a novel blind multi-input multi-output (MIMO) semantic communication (SC) framework named Blind-MIMOSC that consists of a deep joint source-channel coding (DJSCC) transmitter and a diffusion-based blind receiver. The DJSCC transmitter aims to compress and map the source data into the transmitted signal by exploiting the structural characteristics of the source data, while the diffusion-based blind receiver employs a parallel variational diffusion (PVD) model to simultaneously recover the channel and the source data from the received signal without using any pilots. The PVD model leverages two pre-trained score networks to characterize the prior information of the channel and the source data, operating in a plug-and-play manner during inference. This design allows only the affected network to be retrained when channel conditions or source datasets change, avoiding the complicated full-network retraining required by end-to-end methods. This work presents the first fully pilot-free solution for joint channel estimation and source recovery in block-fading MIMO systems. Extensive experiments show that Blind-MIMOSC with PVD achieves superior channel and source recovery accuracy compared to state-of-the-art approaches, with drastically reduced channel bandwidth ratio.