The loading-aware energy saving scheme for EPON networks

This paper proposes an energy saving mechanism in Ethernet passive optical networks (EPONs) for the optical network unit (ONU). It measures traffic loading continuously to identify traffic load for each ONU, then classifies such load to either a low or high loading level. The scheme allows ONU to transmit packets only when the system stays in high load conditions, otherwise ONU changes to one of power saving modes. Therefore, ONU can accumulate queued packets in low-load scenario and stay in power saving mode for longer duration. However, in order to avoid long queueing delay of high priority packets, the ONU will not switch to power saving mode, if the queue of high priority packets is not empty. Comparing to a previous proposed tri-mode energy saving scheme which imposed strict restriction on ONU's staying in energy saving modes, the proposed scheme achieves energy saving improvement without suffering noticeable delay performance degradation.