Energy-efficient Dynamic Bandwidth Allocation for EPON networks with sleep mode ONUs

Putting no-load Optical Network Units (ONUs) into sleep mode has been recognized as a promising solution to achieve high energy efficiency for Ethernet Passive Optical Networks (EPONs). To minimize ONU active time, the upstream and downstream transmission windows of each ONU should be overlapped as much as possible. However, the existing Dynamic Bandwidth Allocation (DBA) schemes for EPONs only consider the upstream bandwidth requests. In this paper, we design a novel energy-efficient DBA framework to reduce energy consumption, and meanwhile to guarantee network performance based on bandwidth requests in both downstream and upstream directions. Our DBA framework includes an energy-efficient MAC control scheme, a grant sizing policy and two grant scheduling algorithms. With the MAC control scheme, the Optical Line Terminal (OLT) allocates transmission windows to all ONUs and puts them into low power mode (sleep or doze mode) in each polling cycle. We formulate the energy efficient grant scheduling problem and introduce two energy-efficient grant scheduling algorithms to solve this problem. Results show the effectiveness of the proposed framework and highlight the merits of our algorithms.