Optimization of sleep period in watchful sleep mode for power-efficient passive optical networks

The energy consumption in data communication networks has drawn global attention due to the ever-increasing of broadband users. In this paper, we formulated the system performances of the watchful sleep mode in terms of the power consumption and the state transition delay by using the state probability based on arrival traffic profile. And we compared the performances of the watchful sleep mode with the cyclic sleep mode under the same conditions. For above two conflicting performance indexes, the Sleep period is a key factor. Thus we designed the Cost function to determine the balanced Sleep periods for the certain requirements of power saving and state transition delay. And the simulation results verified the balanced Sleep period can greatly improves the system performances.