Study On Energy-saving Techniques For Passive Optical Networks

In recent years,with the rapid growth of broadband services such as video phone,IPTV,video on demand,the global broadband access network is developed to warding higher rates continuously.The passive optical network(PON)is recognized as the most promising technology and deployed widely around the world,because of the high bandwidth,reliability and high capacity,but it was widely deployed and the data rate keeps rising,which would sharply increase the energy cosumptions;thus,how to effectively reduce the energy consumption of PON network has become a highly academic and practical research hotspot.ITU-T standard defines the four ONU sleep energy saving modes,which Cycle Sleep mode and Doze mode are currently widely studied for the sleep energy saving mode.Model the cyclic sleep mode based on the Markov chain,and it is critical to design the specific performance parameters of dynamic management mechanism for Cyclic sleep mode-sleep period,which balance the performance tradeoff between these two important and conflicting goals:energy saving efficiency and quality of service(state transition delay).The longer sleep period of the ONU bring the better energy savings,but it result in the larger data packet delay,even lead to data packet loss.Four sleep period variation patterns(Constant,Linear-1,Linear-2 and Exponential patterns)are designed to study the impact of these extended sleep periods on the ONU performances;According to the simulation results,with the arrival traffic rate increases,the Exponential pattern presents the best ESE and the worst DPD performances.Define the cost function to determine a minimum cost under the certain pattern,and to obtain the optimal balance between the two conflicting indexes.Though the extensive simulations,the power-saving efficiency and the data packet delay would become saturated,when the number of SaS state pairs is greater than a certain value;and the optimal cost can be achieved by setting a limited smaller number of the state pairs in the cyclic sleep mode.