Deep Joint CSI Estimation-Feedback-Precoding for MU-MIMO OFDM Systems

Abstract: As the number of antennas in frequency-division duplex (FDD) multiple-input multiple-output (MIMO) systems increases, acquiring channel state information (CSI) becomes increasingly challenging due to limited spectral resources and feedback overhead. In this paper, we propose an end-to-end network that conducts joint design with pilot design, CSI estimation, CSI feedback, and precoding design in the multi-user MIMO orthogonal frequency-division multiplexing (OFDM) scenario. Multiple communication modules are jointly designed and trained with a common optimization objective to prevent mismatches between modules and discrepancies between individual module objectives and the final system goal. Experimental results demonstrate that, under the same feedback and CE overheads, the proposed joint multi-module end-to-end network achieves a higher multi-user downlink spectral efficiency than traditional algorithms based on separate architecture and partially separated artificial intelligence-based network architectures under comparable channel quality. Furthermore, compared to conventional separate architecture, the proposed network architecture with joint architecture reduces the computational burden and model storage overhead at the UE side, facilitating the deployment of low-overhead multi-module joint architectures in practice. While slightly increasing storage requirements at the base station, it reduces computational complexity and precoding design delay, effectively reducing the effects of channel aging challenges.