Multicast tree allocation algorithms for distributed interactive simulation

We deal with a way of realizing real-time communications required by a distributed interactive simulation (DIS), using multipoint communication technics. These technics would be the basic principles of the data distributed management (DDM) of the simulation tool. We focus here on a classical interactive game between participants distributed on a geographic map, where each participant is associated to a square cell on it. The needs of communication between participants (i.e., if the associated cells overlap) are represented by a graph called {\em neighborhood graph}. The problem we deal with consists in covering efficiently the neighborhood graphs by groups of nodes (such that each edge is covered by at least one group), and in allocating in the target network a subtree with a given bandwidth to each group. After giving the formal definition of the considered problem, we show that it is NP-complete. Then, we give some lower bounds technics. Finally, we give two heuristics to solve this problem and we analyse them