  We consider the well-posedness problem of multi-dimensional reflected
backward stochastic differential equations driven by $G$-Brownian motion
($G$-BSDEs) with diagonal generators. Two methods, i.e., the penalization
method and the Picard iteration argument, are provided to prove the existence
and uniqueness of solutions. We also study its connection with the obstacle
problem of a system of fully nonlinear PDEs.
