  We adopt artificial $\Lambda$-type three-level system with superconducting
devices for microwave signal detection, where the signal intensity reaches the
level of discrete photons instead of continuous waveform. Based on the state
transition principles of the three-level system, we propose a statistical model
for microwave signal detection. Moreover, we investigate the achievable
transmission rate and signal detection based on the statistical model. It is
predicted that the proposed detection can achieve significantly higher
sensitivity compared with the currently deployed 4G/5G communication system. We
further characterize the received signal considering the saturation phonomenon,
which reveals negligible performance degradation caused by saturation under
weak received power regime.
