Demonstration of timer-based ONU deep sleep for emergency communication during power failure

Telephone services provided via optical fiber cable become unavailable when the electrical power to a Voice over IP (VoIP) adapter or an optical network unit (ONU) on a customer´s premises is lost, which is not the case with conventional services provided via copper cable. Additionally, maintaining phone service availability with a limited capacity battery is becoming more difficult even with the current power-saving standards because of the increased power consumption of higher-speed devices. This paper contributes to the realization of reliable lifeline services in the following three ways. First, it describes our energy-efficient timer-based deep sleep technique that temporarily shuts down almost all the components that comprise an ONU. The characteristic advantage of our proposal is that it enables an incoming phone call to be received at the ONU side without the support of an optical line terminal (OLT). Second, it provides a concrete demonstration of the proposed ONU deep sleep technique, which shows that it reduces the power consumption of the ONU by more than a half compared with the conventional sleep approach. Lastly, it describes a quality-of-service (QoS) analysis that calculates the increased caller wait time caused by the deep sleep before a phone call is established.