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Downstream-based Scheduling for Energy Conservation in Green EPONs

Shen Chen1, Ahmad R. Dhaini2, Pin-Han Ho1,2, Basem Shihada3, Gangxiang Shen2, and Chih-Hao Lin4
1. Dept. of Electronic and Information Science, Soochow University, China
2. Dept. of Electrical and Computer Engineering, University of Waterloo, Canada
3. MCSE Division, King Abdullah University of Science & Technology, Thuwal, KSA
4. Dept. of Information Management, Chung Yuan Christian University, Taiwan, Republic of China

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