Optimizing Reconfiguration Triggering upon Load Fluctuations in Energy-Efficient TWDM PONs

When traffic carried by a Time and Wavelength Division Multiplexed (TWDM) PON is fluctuating, the network performance, both in terms of energy efficiency and delay, is heavily impacted by the decision of when network reconfiguration (i.e., switching OSUs from active mode to sleep mode and vice versa) is triggered. This paper provides hints on when to trigger a network reconfiguration is such scenario by considering also the ONU tuning time. Results show that reconfigurations shall follow as soon as possible traffic variations. However, if traffic variations are fast, the ONU tuning time impairs delay performance. Therefore, when traffic variations are fast, it is better not to reconfigure the network at the expense of a higher energy consumption.