Decentralized SIEPON-based ONU-initiated Tx/TRx energy-efficiency mechanism in EPON

An Ethernet passive optical network (EPON) has the least energy consumption among access network technologies and is the best candidate for improving energy consumption by time utilization. Current studies have proposed OLT-initiated schemes to turn off the transmitter/ receiver of an optical network unit (ONU) for a substantial time in order to achieve energy savings. In this paper, a new SIEPON-based ONU-initiated energy-saving mechanism is proposed in which the ONU calculates the transmitter (Tx) sleep duration based on the current queue state and maximum boundary delay requirements and forwards it to the OLT; then, the OLT calculates the ONU's receiver (Rx) sleep duration and decides the ONU's sleeping mode in Tx or TRx sleep mode. Furthermore, the Sleep manager and Green DBA and TRx controller components are proposed in the OLT and ONU architectures to more precisely manage the energy-saving mechanism. Simulation results show that the proposed energy-saving mechanism significantly improves energy savings up to 47% and 42% in the up- and downstream directions, respectively, and guarantees the QoS requirement in terms of mean packet delay, packet loss, throughput, and jitter. Moreover, the proposed energysaving mechanism has better delay performance compared with the OLT-initiated energy-saving mechanism such as upstream centric scheduling.