SLA-Aware Protocol Design for Energy-Efficient OLT Transmitter in TWDM-EPON

Environmental and economic concerns promote research on designing energy-efficient Time and Wavelength Division Multiplexed Ethernet Passive Optical Network (TWDM-EPON). TWDM-EPON allows achieving energy efficiency at the Optical Line Terminal (OLT) along with Optical Network Units (ONUs). All existing protocols for energy efficient TWDM-EPON have primarily been designed for saving energy at the OLT receivers. In this paper, we propose a method for saving energy at the OLT transmitter in TWDM-EPON while satisfying the service level agreements (SLAs) of corresponding downstream traffic. This includes a proposal for a heuristic algorithm that exploits some specific features of downstream scheduling in TWDM-EPON. Through extensive simulations, we demonstrate that the proposed method provides a significant improvement in energy efficiency in comparison with existing DBA protocols (up to ~ 45%). Moreover, we analyse a theoretical lower bound of the probability of delay bound violation (SLA parameter) and through simulations, we have demonstrated that delay bound violation probability of our proposed protocol is close to this lower bound.