Power saving specially on battery operated devices need to be kept, in this application note from ON Semiconductors discussed how to keep duty cycle in which a wireless RF device is operated at a minimum time. Link here (PDF)
Consider a battery powered device (target), which should receive data from a second device (initiator) from time to time. To reduce power consumption, the target switches its receiver on for only a short while, checking if there is any RF activity, and returns to sleep if there is no data to receive.
The ratio of the time ton during which the target is powered on, to the time toff during which the target is powered off is called duty cycle. If for example the target is powered off for 1 second, powered on for 1 millisecond, powered off for 1 second and so on, its duty cycle is 1:1000.
