Methods and systems for scheduling wake/sleep cycles by a central device in a wireless network that have at least one mobile device include determining a system reference cycle as a minimum value of a delay constraint on a real-time service for each mobile device of the at least one mobile device that has a real-time service. A wake/sleep cycle length is attributed to each mobile device. The wake/sleep cycle length is an integer multiple of the system reference cycle such that a wake/sleep cycle length of a first mobile device is different from that of a second mobile device. A sleep period and a wake period are assigned within the wake/sleep cycle of each mobile device. The wake/sleep cycle of each mobile device is arranged to avoid collision of the wake period with those of other mobile devices.