  This paper gives a new solution to the output feedback H_2 model matching
problem for a large class of delayed information sharing patterns. Existing
methods for such problems typically reduce the decentralized problem to a
centralized problem of higher state dimension. In contrast, the controller
given in this paper is constructed from the solutions to the centralized
control and estimation Riccati equations for the original system. The problem
is solved by decomposing the controller into two components. One is
centralized, but delayed, while the other is decentralized with finite impulse
response (FIR). It is then shown that the optimal controller can be constructed
through a combination of centralized spectral factorization and quadratic
programming.
