Delay fairness in reconfigurable and energy efficient TWDM PON

In this study, the impact of the ONU scheduling and assignment to OSUs upon network reconfiguration on the average frame delay unbalance is evaluated. Then, a method that balances the average frame delay by swapping the tuning ONU upon reconfiguration is proposed, for some critical scenarios. Simulation and experimental results show that the delay unbalance is large when the number of active ONUs is small (e.g., at network start up or when the majority of the ONUs is inactive/sleeping). In this case, the proposed method effectively balances the delay experienced by ONUs without impacting the OLT energy savings.