A network device may be configured to iteratively modify an initial tone map for each communication region of a powerline cycle to minimize the time before application data can be transmitted. A first network device estimates an initial tone map for each communication region based, at least in part, on sounding messages received from a second network device. The first network device determines whether to estimate a modified tone map for the first communication region based on at least one performance measurement associated with a data packet generated using the initial tone map for the first communication region. If so, the second network device retransmits the sounding messages in the first communication region that will be used to modify the initial tone map for the first communication region, and the second network device continues to transmit the data packets using the initial tone maps in the remaining communication regions.