An Equivalent Baseband Signal Model for Rydberg Atomic Quantum Receiver Aided Wireless Communications and Sensing

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.