  Intelligent reflecting surface (IRS) has recently been identified as a
prominent technology with the ability of enhancing wireless communication by
dynamically manipulating the propagation environment. This paper investigates a
multiple-input single-output (MISO) system deploying distributed IRSs. For
practical considerations, we propose an efficient design of passive reflecting
beamforming for the IRSs to exploit statistical channel state information (CSI)
and analyze the achievable rate of the network taking into account the impact
of CSI estimation error. The ergodic achievable rate is derived in a closed
form, which provides insightful system design guidelines. Numerical results
confirm the accuracy of the derived results and unveil the performance
superiority of the proposed distributed IRS deployment over the conventional
centralized deployment.
