Novel Channel Estimation Based on Enhanced Diffusion Posterior Sampling for mmWave MIMO Systems

In this letter, a novel diffusion model (DM)-based channel estimation method is proposed to mitigate abrupt performance degradation in millimeter wave (mmWave) multiple-input multiple-output (MIMO) systems under severe pilot scarcity. To address this issue, the proposed method jointly exploits first- and second-order posterior moments using the moment matching principle and Tweedie’s formula. This method improves estimation accuracy and robustness under high uncertainties, while maintaining a comparable computational burden. From the simulation results, it is confirmed that the proposed method successfully mitigates the abrupt performance degradation. The proposed method also substantially outperforms state-of-the-art DM-based methods in estimation accuracy under severe pilot scarcity, while achieving comparable computational complexity.