Sleep control for energy efficiency in ethernet passive optical networks

摘要

A method sets certain downstream traffic scheduling rules at an optical line terminal OLT and certain sleep control rules at optical network units ONUs. Both downstream traffic scheduling rules and sleep control rules are common information owned by both the OLT and ONUs. The method sets the traffic scheduling rules that each ONU is allocated with some time slots every cycle if the ONU has downstream traffic. Rather than using a control message to notify ONUs with their queue status, the method lets ONUs infer whether its downstream queue is empty or not based on downstream traffic scheduling and lets the OLT infer the status of an ONU based on sleep control rules.

主权项

1. A method for controlling downstream scheduling in an Ethernet passive optical network EPON, said method comprising the steps of:
i) setting downstream traffic scheduling rules at an optical line terminal OLT for a plurality of ONUs, comprising:
defining a time duration of 2 ms as a downstream traffic scheduling cycle;in a scheduling cycle, allocating each ONU with some time duration if it has downstream traffic, wherein ONUs need not be allocated with continuous time durations within a scheduling cycle; andif said OLT infers that an ONU is sleeping, said OLT queuing the arrival of downstream traffic of the ONU until said ONU wakes up; ii) transmitting said rules to optical network units ONUs, each ONU owning information of the downstream traffic scheduling rules, such that the ONU infers its current downstream queue status based on historical arrival downstream traffic; iii) according to the inferred queue status, said ONUs making their own sleep decisions based on selective sleep control rules, said sleep control rules, being implemented at said ONUs, being known by said OLT; and iv) based on said sleep control rules, said OLT inferring a status of said ONUs, and buffering incoming downstream traffic of sleeping ONUs responsively.