A method, of operating an end node to wirelessly communicate with a central node, includes: receiving wirelessly a current instance of a beacon signal periodically-transmitted from the central node; measuring a received power, PB-RX, of the beacon signal; reading locally-stored values of PB-TX and G representing a presumed transmitted power of the beacon signal and a performance goal of the end node, respectively; determining, for a given channel, a path loss, PL, based on the PB-RX and the PB-TX; and adaptively setting an energy level, EN-TX, of a forthcoming message to be transmitted from the end node by adaptively determining, based on PL and G, at least two of: a level of power, PN-TX; a forward error correction coding rate, c; and a spreading factor, SF; and a modulation format, M.