The Minimum Broadcast Time Problem

Broadcasting is the information dissemination process in a communication network. A subset of processors V0 (V called originators knows an unique message which has to be transferred by calls between adjacent processors. Each call requires one time unit and each processor can participate in at most one call per time unit. The problem is to find a schedule such that the time needed to inform all processors is less than or equal to a deadline k e IN. We present NP-completeness results for this problem restricted to several communication networks (bipartite planar graphs, grid graphs, complete ρid graphs, split graphs and chordal graphs) with constant deadline k=2 or one originator V0={v}.