Rydberg atomic quantum receivers (RAQRs) offer quantum-limited sensitivity and broadband tunability. It is not obvious whether this device-level advantage also improves network reliability, since in dense deployments, aggregate interference can push the atomic transducer out of its small-signal regime. This paper addresses the question by embedding the RAQR front end into a stochastic geometry (SG) coverage analysis. Starting with the atomic master equation and balanced coherent optical detection, we derive a third-order complex baseband model that retains both the linear gain and the leading cubic nonlinearity. A Bussgang decomposition converts the per-element nonlinear response into an equivalent linear gain plus a distance-dependent distortion noise. Using this equivalent model, we derive the post maximal-ratio combining (MRC) SINR and obtain tractable expressions for the conditional and spatially averaged coverage probabilities. The analytical results show that RAQRs outperform conventional receivers in sparse deployments. However, when the base station (BS) density becomes large, nonlinear distortion reduces this advantage and may make RAQRs perform worse. Simulation results validate the analytical expressions and confirm that the central design tradeoff is between linear gain and cubic nonlinearity.
Rydberg atomic quantum receivers (RAQRs) offer quantum-limited sensitivity and broadband tunability. It is not obvious whether this device-level advantage also improves network reliability, since in dense deployments, aggregate interference can push the atomic transducer out of its small-signal regime. This paper addresses the question by embedding the RAQR front end into a stochastic geometry (SG) coverage analysis. Starting with the atomic master equation and balanced coherent optical detection, we derive a third-order complex baseband model that retains both the linear gain and the leading cubic nonlinearity. A Bussgang decomposition converts the per-element nonlinear response into an equivalent linear gain plus a distance-dependent distortion noise. Using this equivalent model, we derive the post maximal-ratio combining (MRC) SINR and obtain tractable expressions for the conditional and spatially averaged coverage probabilities. The analytical results show that RAQRs outperform conventional receivers in sparse deployments. However, when the base station (BS) density becomes large, nonlinear distortion reduces this advantage and may make RAQRs perform worse. Simulation results validate the analytical expressions and confirm that the central design tradeoff is between linear gain and cubic nonlinearity.
In this paper, we develop a communication-oriented complex baseband equivalent model for superheterodyne Rydberg atomic quantum receivers (RAQRs). The model explicitly captures photodetection-induced signal-dependent shot noise and its coupling with the optical operating point. By leveraging an atomic superheterodyne architecture and a strong local oscillator, we construct a complex baseband representation for both the received signal and the signal-dependent shot noise under both direct incoherent optical detection and balanced coherent optical detection. The derived model reveals that the optical operating point jointly determines the normalized effective receive gain and the equivalent noise background, thereby establishing a traceable gain-noise tradeoff governed by system design. More importantly, the proposed model shows that neglecting signal-dependent shot noise may lead to inaccurate operating-point design. Finally, by extending to the multiple-input-multiple-output (MIMO) case, we derive a lower bound on the achievable rate while considering the signal-dependent shot noise. Our analysis \textcolor{black}{reveals} that the non-zero asymptotic rate of RAQ-MIMO and its superiority over conventional RF-MIMO hinge on the normalized noise floor of the RAQ receive chain falling below that of RF MIMO. Simulation results validate our analysis and yield practical, closed-form design guidelines for RAQR front ends, revealing parameter regimes in which RAQ-MIMO outperforms conventional MIMO systems.
Next-generation Internet-of-Things (IoT) is evolving toward a ubiquitous, ultra-low-power, and multi-band heterogeneous networking paradigm that seamlessly integrates terrestrial, non-terrestrial, and ambient devices. This vision places unprecedented demands on conventional radio frequency (RF) receivers, whose fundamental bottlenecks in sensitivity, power consumption, coverage, and multi-band operation are rooted in the RF antenna. To tackle these issues, we show that the quantum properties of Rydberg atomic quantum receivers (RAQRs), including ultra-high sensitivity, broad frequency agility, and diverse reception modalities, provide a physically distinct receiver-side path that replaces the conventional antenna-and-low-noise-amplifier chain. Using LoRa, narrowband IoT, and ambient IoT as case studies, this article shows that RAQRs deliver significant gains in weak-uplink, low-power, and battery-free regimes. A stochastic-geometry analysis in cellular and cell-free architectures then maps these device-level gains onto network coverage, where the RAQR retains roughly a 4 dB half-coverage advantage over the RF receiver in sparse deployments at λ∼10−5m−2, with the gain eroded as device density grows. The open challenges are presented to stand between current RAQR prototypes and deployable IoT infrastructure.
Rydberg-atom quantum receivers (RAQRs) offer highly sensitive RF reception, but their communication performance depends jointly on atomic response, optical transduction, receiver noise, bandwidth, and wireless-channel conditions. This paper develops a BER-aware communication-theoretic framework for superheterodyne RAQR-assisted wireless communication, linking four-level Rydberg-atom dynamics and coherent optical detection to multipath propagation and digital communication performance. Closed-form instantaneous and average SNR and BER expressions are derived for square Gray-coded M-QAM over correlated Rayleigh fading. The RAQR operating point is then jointly optimized over atomic, optical, RF, and geometric parameters using analytical block-wise updates within a fixed-point procedure subject to physical and bandwidth constraints. Numerical results demonstrate substantial gains in low-power reception, bandwidth utilization, robustness to detuning, fading and delay spread, outage, and communication coverage compared with conventional, advanced, and fixed-point RAQR receivers. The results demonstrate that BER-aware joint optimization translates the intrinsic sensitivity of Rydberg-atom sensing into tangible communication-level gains.
Rydberg atomic quantum receivers (RAQRs) emerge as a radical solution for detecting radio frequency (RF) signals, showing great potential in assisting classical wireless communications and sensing. However, the current studies of RAQRs mainly focus on realizing fundamental functionalities via experiments, where the results cannot be readily harnessed for assisting wireless communications and sensing. Moreover, the advantages of RAQR-based wireless receivers have not been fully characterized. To fill the gap, we introduce the superheterodyne version of RAQRs and present the associated end-to-end transmission scheme. We then develop a corresponding end-to-end equivalent baseband signal model relying on a realistic transmission flow. Our scheme and model provide explicit design guidance for RAQR-aided wireless systems. We finally verify the effectiveness of the proposed signal model with respect to the waveform of the photodetector, input-output relationship (transfer function), and the normalized mean-squared error between the nonlinear transfer function and its linear approximation.
Rydberg atomic quantum receivers (RAQRs) have recently emerged as a promising technology for radio-frequency (RF) reception by directly transducing incident RF fields into optical signals. Existing receiver architectures, however, exploit only subsets of the dipole-allowed transitions within a given atomic manifold, limiting the number of simultaneously accessible RF channels. In this paper, a hybrid six-level Rydberg atomic quantum receiver (H-RAQR) is proposed by integrating parallel and cascaded RF coupling pathways within a single vapor-cell receiver. A communication-oriented analytical framework is developed by deriving a closed-form steady-state atom--field interaction model and establishing an equivalent baseband signal representation. The achievable ergodic sum rate is analyzed, and a resource-efficiency metric is introduced to quantify throughput per unit optical receiver resource. The analytical model is validated against full Lindblad master-equation simulations over its identified operating region. Numerical results show that the proposed H-RAQR supports four simultaneous RF channels within a single atomic system, achieves higher ergodic sum rate than conventional parallel Rydberg state (PRS) and cascade Rydberg state (CRS) receivers, and provides about 29% higher resource efficiency than a combined PRS-CRS deployment with equivalent four-band coverage. The proposed framework provides a scalable foundation for multi-band atomic wireless receivers.
The significant progress of quantum sensing technologies offer numerous radical solutions for measuring a multitude of physical quantities at an unprecedented precision. Among them, Rydberg atomic quantum receivers (RAQRs) emerge as an eminent solution for detecting the electric field of radio frequency (RF) signals, exhibiting great potential in assisting classical wireless communications and sensing. So far, most experimental studies have aimed for the proof of physical concepts to reveal its promise, while the practical signal model of RAQR-aided wireless communications and sensing remained under-explored. Furthermore, the performance of RAQR-based wireless receivers and their advantages over classical RF receivers have not been fully characterized. To fill these gaps, we introduce the RAQR to the wireless community by presenting an end-to-end reception scheme. We then develop a corresponding equivalent baseband signal model relying on a realistic reception flow. Our scheme and model provide explicit design guidance to RAQR-aided wireless systems. We next study the performance of RAQR-aided wireless systems based on our model, and compare them to classical RF receivers. The results show that Doppler broadening-free RAQRs are capable of achieving a substantial received signal-to-noise ratio (SNR) gain of over 27 decibel (dB) and 40 dB in the photon shot limit and standard quantum limit regimes, respectively.