Cross Layer Analysis on ONU Energy Consumption in Smart FiWi Networks

Smart Fiber Wireless (SFiWi) networks have attracted great attention due to their ability to become the next generation broadband access networks. FiWi networks integrate optical networks and wireless networks. Access networks consume much energy due to the increase of network participants and the volume of content. To conserve energy consumption in Passive Optical Network (PON), Optical Network Unit (ONU) sleep mode was proposed. The basic idea of ONU sleep mode is to enter sleep state, for an ONU sleep state period while the ONU is in idle situation. Traditional research on ONU sleep showed that long ONU sleep state period results only in increased latency. In this research we prove that excessively long ONU sleep state periods not only cause long latency but also result in more energy consumption. Furthermore, we derive the optimal sleep state period to minimize energy consumption. Also, we show that our derived sleep state period achieves better latency compared to large ONU sleep state period.