Abstract—Maximizing the optical network unit’s (ONU) sleep time is an effective approach for achieving maxi¬mum energy conservation in green Ethernet passive optical networks (EPONs). While overlapping downstream and upstream ONU transmissions can maximize the ONU sleep time, it jeopardizes the quality of service (QoS) performance of the network, especially for downstream trafﬁc in case the overlapping is based on the upstream time slot. In this paper, we study the downstream trafﬁc performance in green EPONs under the limited service discipline and the upstream-based overlapped time window. Speciﬁcally, we ﬁrst derive the expected mean packet delay, and then present a closed-form expression of the ONU sleep time, setting identical upstream/downstream transmission cycle times based on a maximum downstream trafﬁc delay re-quirement. With the proposed system model, we present a novel downstream bandwidth allocation scheme for energy conservation in green EPONs. Simulation results verify the proposed model and highlight the advantages of our scheme over conventional approaches.
Index Terms—Green EPON, Dynamic Bandwidth Alloca¬tion, Queuing Theory, Energy Efﬁciency.
Cite:Shen Chen, Ahmad R. Dhaini, Pin-Han Ho, Basem Shihada, Gangxiang Shen, and Chih-Hao Lin , "Downstream-based Scheduling for Energy Conservation in Green EPONs," Journal of Communications, vol. 7, no.5, pp.400-408, 2012. Doi: 10.4304/jcm.7.5.400-408
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