  Intelligent reflecting surface (IRS) has recently emerged as a new solution
to enhance wireless communication performance via passive signal reflection. In
this letter, we unlock the potential of IRS controller in relaying information
and propose a novel IRS-assisted communication system with both IRS passive
reflection and active relaying. Specifically, we jointly optimize the time
allocations for decode-and-forward (DF) relaying by the IRS controller and the
IRS passive beamforming to maximize the achievable rate of the proposed system.
We also compare the rate performance of the proposed system with the
conventional IRS without relaying, and reveal the conditions for one to
outperform the other. Simulation results demonstrate that the proposed new
design can significantly improve the coverage/rate performance of IRS-assisted
systems.
