Résumé
In this paper, we study the distance-2 broadcast scheduling problem in synchronous wireless networks of known topology. Two constraints are taken under consideration: the schedule must be collision-free and the nodes at distance 2 must be informed by nodes at distance 1. In general graphs, a tight bound of O(log(n) 2 ) slots to complete the broadcast is known, n being the number of nodes at distance 2. We improve this bound to O(log(n)) in unit disk graphs, and to O(1) when the neighbourhoods of the nodes are circular intervals.