Towards Atomic MIMO Receivers

The advancement of Rydberg atoms in quantum sensing 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 and sensing. Although the atomic receiver is developing rapidly in quantum-sensing domain, its integration with wireless communications is still 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) communication to implement atomic-MIMO receivers. Specifically, we establish the framework of atomic-MIMO receivers exploiting the principle of quantum sensing, and reveal that its signal detection is intrinsically a non-linear biased phase-retrieval (PR) problem, as opposed to the linear model in classical MIMO systems. To this end, we modify the Gerchberg-Saxton (GS) algorithm, a typical PR solver, with a biased GS algorithm to solve the discovered biased PR problem. Moreover, we propose an Expectation-Maximization-GS (EM-GS) algorithm by introducing a high-pass filter constructed by Bessel functions into the iteration of GS, which improves the detection accuracy efficiently. Finally, the effectiveness of atomic MIMO receivers is demonstrated by theoretical analysis and numerical simulation.