Multi-User SIMO Wireless Communications Based on Atomic Receivers

The advancement of Rydberg atoms is driving a paradigm shift from classical receivers to atomic receivers. Capitalizing on the extreme sensitivity of Rydberg atoms to external disturbance, atomic receivers can measure radio waves more precisely than classical receivers to support high-performance wireless communication. Although the atomic receiver is developing rapidly in the field of quantum physics, its integration with wireless communications is at a nascent stage. Particularly, systematic methods to enhance communication performance through this integration are largely uncharted. Motivated by this observation, we propose to incorporate atomic receivers into multiple-input multiple-output (MIMO) communications to implement atomic-MIMO receivers. We establish the framework of atomic-MIMO receivers by exploiting the principle of quantum sensing. Our model reveals that the signal detection of atomic-MIMO systems is intrinsically a nonlinear phase-retrieval problem, as opposed to the linear model in classical MIMO systems. To perform atomic-MIMO signal detection, we propose an Expectation-Maximization-Gerchberg-Saxton (EM-GS) algorithm based on the maximum likelihood (ML) criteria. Its novelty lies in treating the unobserved phase information as a latent variable and thereby decoupling the intricate ML problem into a sequence of tractable linear regression problems with analytical solutions. Experimental results validate the effectiveness of detecting atomic-MIMO signals using the EM-GS algorithm.