Core Concepts
The authors propose a novel framework for atomic MIMO receivers that leverages the extreme sensitivity of Rydberg atoms to electromagnetic fields for high-precision signal detection. The key challenge of non-linear biased phase retrieval is addressed through the design of biased Gerchberg-Saxton and Expectation-Maximization Gerchberg-Saxton algorithms.
Abstract
The article introduces the concept of atomic receivers, which utilize Rydberg atoms as "antennas" to detect electromagnetic waves with high accuracy and sensitivity. It then proposes a framework for integrating atomic receivers into multiple-input-multiple-output (MIMO) wireless communication systems.
The key findings are:
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Modeling of atomic MIMO receiver: The signal detection in atomic MIMO receivers corresponds to a non-linear biased phase retrieval (PR) problem, in contrast to the linear Gaussian model in classical MIMO systems.
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Signal detection algorithms:
- Biased Gerchberg-Saxton (GS) algorithm: Extends the classic GS algorithm to eliminate the bias caused by the reference source.
- Expectation-Maximization GS (EM-GS) algorithm: Employs Bayesian regression to perform maximum likelihood detection, introducing a high-pass filter to improve accuracy without increasing complexity.
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Performance analysis:
- The EM-GS algorithm consistently approaches the Cramér-Rao lower bound and outperforms the biased GS algorithm, especially in the low signal-to-noise ratio regime.
- Both algorithms achieve bit error rates close to an exhaustive search, while being much more computationally efficient.
The article demonstrates the feasibility of atomic MIMO receivers and the effectiveness of the proposed detection algorithms, paving the way for integrating quantum sensing into next-generation wireless communications.
Stats
The incident electromagnetic wave is given as E(t) = ϵ√Pρs cos(ωt + φ), where ϵ is the polarization direction, P is the transmit power, ρ is the path loss, s is the baseband signal, ω is the carrier frequency, and φ is the phase shift.
The probability of the electron being in the excited state is |αe(t)|2 = Ω2
R/(Ω2
R + δ2) sin2(√Ω2
R + δ2/2 t), where ΩR is the Rabi frequency and δ is the detuning.
The splitting interval Δf of the probe-beam spectrum is linearly proportional to the effective Rabi frequency Ω = √Ω2
R + δ2.
Quotes
"Atomic receivers are capable of realizing more precise radio-wave measurements than RF receivers to support high-performance wireless communication and sensing."
"The atomic MIMO receiver capitalizes on the strength of the coupling between the electric dipole moment of Rydberg atoms and the incident radio waves to infer multi-user symbols without the help of phase information."
"The proposed EM-GS algorithm employs the Bayesian regression to perform ML detection, 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."