Trading energy savings and network performance in reconfigurable TWDM-PONS

In time and wavelength division multiplexed (TWDM) passive optical networks (PONs), energy savings at the optical line termination (OLT) are achievable by dynamically allocating the number of active wavelengths in the network and by turning off unutilized OLT transceivers. However, optical network unit (ONU) and PON parameters might impact network performance. This paper evaluates the impact of ONU parameters (e.g., transceiver tuning time) and other PON parameters (e.g., reconfiguration period) on OLT energy savings and average frame delay when dynamic wavelength allocation is performed periodically. Results show that the average frame delay is mainly affected by tuning time and reconfiguration period with lower absolute values if only one ONU buffers traffic during tuning. Increased tuning time trades increased delay with increased energy savings while increased reconfiguration period trades decreased delay with decreased energy savings.