A Polynomial Algorithm for Minimizing Communication in a Distributed Discrete Event System with a Central Station

The problem of minimizing communication in distributed systems is considered in a discrete-event formalism where the system is modeled as a finite-state automaton. There are a central station and a set of N communicating local agents observing the behavior of the system. The central station needs to know exactly the state of the system, whereas local agents need to disambiguate certain pre-specified pairs of states for purposes of control or diagnosis. Communication occurs only between the central station and local agents but not among local agents. A set of communication policies is said to be minimal if communications cannot be removed without affecting the correctness of the solution. Under an assumption on the absence of cycles (other than self-loops) in the system model, an algorithm that computes a set of minimal communication policies in polynomial-time in all input variables of the system is presented. These results improve upon algorithms for solving minimum communication problems