Optimal deterministic broadcasting in known topology radio networks

We consider deterministic broadcasting in radio networks whose nodes have full topological information about the network. The aim is to design a polynomial algorithm which given a graph G with source s produces a fast broadcast scheme in the radio network represented by G. The problem of finding a fastest broadcast scheme for a given graph is NP-hard hence it is only possible to get an approximation algorithm. We give a deterministic polynomial algorithm which produces a broadcast scheme of length O(D + 2 n) for every n-node graph of diameter D thus improving a result of Ga̧sieniec et al. (PODC 2005) [17] and solving a problem stated there. Unless the inclusion NP BPTIME(O n holds the length O n) of a polynomially constructible deterministic broadcast scheme is optimal.