Request Satisfaction Problem in Synchronous Radio Networks

摘要

We study two algorithmical problems inspired from routing constraints in a multihop synchronous radio network. Our objective is to satisfy a given set of communication requests in the following model: nodes send omnidirectional radio transmissions in synchronous slots; during a given slot, a node can receive a message from an adjacent node if and only if no other neighbour is transmitting - otherwise, radio interferences may occur if two or more neighbors transmit in the same slot -. The objective is to minimize the number of slots used. The two problems differ in that the routing policy may be imposed (DAWN-path), or not (DAWN-request). In this second case, a path must be assigned for each request, to define the nodes to use to reach the destination from the source. We present some complexity results, in particular showing that both problems are NP-hard when the network is restricted to a tree. We also present a polynomial algorithm in O(n~(2K)) when the number of requests is bounded (by above) by a constant K.