This paper develops a controller synthesis method for distributed LQG control
problems under output-feedback. We consider a system consisting of three
interconnected linear subsystems with a delayed information sharing structure.
While the state-feedback case has previously been solved, the extension to
output-feedback is nontrivial as the classical separation principle fails. To
find the optimal solution, the controller is decomposed into two independent
components: a centralized LQG-optimal controller under delayed state
observations, and a sum of correction terms based on additional local
information available to decision makers. Explicit discrete-time equations are
derived whose solutions are the gains of the optimal controller.Comment: 25 pages, 3 figure