  This paper investigates multiple intelligent reflecting surfaces (IRSs) aided
wireless network, where the IRSs are deployed to cooperatively assist
communications between a multi-antenna base station (BS) and multiple
single-antenna cell-edge users. We aim at maximizing the weighted sum rate of
all the cell-edge users by jointly optimizing the BS's transmit beamforming and
IRS's phase shifts. Especially, the beamforming is optimally solved by the
Lagrangian method, and the phase shifts are obtained based on the Riemannian
manifold conjugate gradient (RMCG) method. Numerical results show that a
significant throughput is improved with aid of multiple IRSs.
