A method of reducing an energy consumption of a wireless network, the method including periodically entering a sleep mode by a receiver node, broadcasting a signal simultaneously across a wide band frequency range, upon waking up from the sleep mode, listening by the receiver node to only a first narrow part of the wide band frequency range, the receiver node subsequently either returning to sleep if a signal strength of the broadcasted signal is less than a predefined signal strength threshold, or staying awake for an additional period of time if the signal strength of the broadcasted signal is greater than the predefined signal strength threshold.