Rydberg Atomic Quantum MIMO Receivers for The Multi-User Uplink

TL;DR

This paper introduces a novel Rydberg atomic quantum MIMO receiver architecture for multi-user uplink wireless communication, deriving formulas for achievable rates and analyzing power scaling and trade-offs in quantum regimes.

Contribution

It proposes a flexible RAQ-MIMO system model, derives asymptotic achievable rate formulas, and analyzes power scaling and trade-offs in quantum communication regimes.

Findings

Achievable rate scales logarithmically with atomic ensemble parameters in SQL regime.

Power can be quadratically scaled down with atomic number while maintaining fixed rate.

Trade-offs between atomic enhancement and attenuation are revealed in PSL regime.

Abstract

Rydberg atomic quantum receivers (RAQRs) have emerged as a promising solution for evolving wireless receivers from the classical to the quantum domain. To further unleash their great potential in wireless communications, we propose a flexible architecture for Rydberg atomic quantum multiple-input multiple-output (RAQ-MIMO) receivers in the multi-user uplink. Then the corresponding signal model of the RAQ-MIMO system is constructed by paving the way from quantum physics to classical wireless communications. Explicitly, we outline the associated operating principles and transmission flow. We also validate the linearity of our model and its feasible region. Based on our model, we derive closed-form asymptotic formulas for the ergodic achievable rate (EAR) of both the maximum-ratio combining (MRC) and zero-forcing (ZF) receivers operating in uncorrelated fading channels (UFC) and the correlated fading channels (CFC), as well as in the standard quantum limit (SQL) and photon shot limit (PSL) regimes, respectively. Furthermore, we unveil that the EAR scales logarithmically without bound with the product of effective number $N_{\text{atom}}$ and coherence time $T_2$ of the atomic ensemble in the SQL regime, but exhibits non-monotonic trade-off between the collective atomic enhancement and optical-depth-dependent attenuation in the PSL regime. More particularly, the transmit power of users can be scaled down quadratically with $N_{\text{atom}} \tau$, $\tau \in \{ T_2, \frac{ {\cal C} (\Omega_{\ell}) }{A_p} \}$, but the EAR per user retains fixed, by increasing $N_{\text{atom}}$ while retaining the sensor number $M \propto N_{\text{atom}} \tau$ in the SQL regime or $M \propto \exp \big( \frac{N_{\text{atom}} {\bar \chi}}{A_p} \big)$ in the PSL regime....