  It was known that a novel quantum communication protocol surpassing the shot
noise limit can be proposed by an atomic indirect measurement based on the
Jaynes-Cummings model. Moreover, the quantum communication with the atomic
indirect measurement can nearly achieve the Helstrom bound as well as the
accessible information when message is transmitted by an ideal coherent state.
Here, we show that the atomic indirect measurement is robust against the
phase-diffusion noise. By considering the error probability of discriminating
received signal, we show that the atomic indirect measurement can also nearly
achieve the Helstrom bound as well as the accessible information even the
channel is exposed to the phase-diffused noise. Moreover, we further show that
atomic indirect measurement outperforms the feedback-excluded receiver composed
of a photon number resolving detector and maximum-a-posteriori decision rule
when the standard deviation of the phase-diffusion channel is not too large.
