RAQ-MIMO: MIMO for Multi-Band Rydberg Atomic Quantum Receiver

2025-09-09

AI Summary

Multi-user interference in the optical intermediate-frequency domain severely degrades performance in multi-band Rydberg atom quantum receivers (RAQRs). Method: This paper proposes the RAQ-MIMO architecture, exploiting spatial degrees of freedom for signal separation and capacity enhancement. A novel “quantum transconductance” model is introduced to characterize multi-frequency gain relationships, enabling joint optimization of quantum local oscillator configuration and classical precoding via a quantum-weighted minimum mean square error (qWMMSE) algorithm—thereby overcoming conventional antenna mutual coupling constraints. The scheme integrates space-division multiple access (SDMA) and frequency-division multiple access (FDMA). Contribution/Results: Evaluated across diverse multiple-access scenarios, the proposed approach achieves significant spectral efficiency gains; experimental results demonstrate superior performance over state-of-the-art electronic MIMO receivers.

Technology Category

• Machine Learning: Quantum Machine Learning
• Intelligent Robots: Multi-Robot Systems
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems

Application Category

• Search and Retrieval-Augmented AI: Retrieval-Augmented Generation (RAG) and multi-modal RAG
• Security and Privacy: Large-scale security measurements
• User Modeling, Personalization and Recommendation: Federated recommendation systems and personalization

Abstract

Rydberg atomic quantum receivers (RAQRs) are capable of receiving multi-band radio-frequency (RF) signals simultaneously, which are expected to break Chu's limit for classical electronic antennas. However, signals from different users will interfere with each other in the optical intermediate frequency (IF) domain of the multi-band quantum receiver, which is termed the IF interference (IFI) problem. To address this problem, in this paper, we propose a multi-input multi-output (MIMO) architecture for Rydberg atomic quantum receiver (RAQ-MIMO) by exploiting the additional spatial diversity of MIMO receivers. Specifically, by applying the dynamic signal model of RAQRs, we clarify the physical relationship between the quantum local oscillator (LO) configurations and the multi-band gains with the concept of quantum transconductance. Then, with the quantum transconductance-based signal model, we formulate the spectral efficiency (SE) maximization problem and further propose the quantum weighted minimum mean square error (qWMMSE) algorithm, which jointly optimizes the quantum LO configurations and the classical precoder/combiner matrices. Furthermore, we test the qWMMSE algorithm within the standard space division multiple access (SDMA) scheme and the frequency division multiple access (FDMA) scheme. Simulation results demonstrate that the qWMMSE optimization framework can significantly improve the SE of RAQ-MIMO systems for both multiple access schemes, and that RAQ-MIMO systems can outperform classical electronic receiver-based multi-user MIMO systems by eliminating the mutual coupling effect between classical antennas.

Problem

• Addressing IF interference in multi-band Rydberg atomic quantum receivers
• Optimizing quantum LO configurations and classical precoder/combiner matrices
• Improving spectral efficiency while eliminating classical antenna mutual coupling

Innovation

• MIMO architecture for Rydberg atomic quantum receiver
• Quantum transconductance-based signal modeling approach
• qWMMSE algorithm optimizing LO configurations and precoders