Load adaptive and fault tolerant framework for energy saving in fiber-wireless access networks

Energy saving (ES) in telecommunication networks is an important criterion when planning access networks. In fiber-wireless (FiWi) access networks the ES potential is high, when compared with other architectures, because different routes and optical access points can be used by routers at the wireless section. Although some proposals to increase energy efficiency in these architectures have been presented, these are not approaches that can adapt to variations in traffic load or distribution of traffic across the network. Here we fill this gap and propose a load adaptive and fault tolerant framework for ES in FiWi access networks. This framework allows optical network units (ONUs) to enter long-standing sleep mode under low traffic conditions, reducing energy waste, permitting fast reaction to ONU or fiber failures, and allowing quality of service (QoS) to be kept at a certain level. Results show that significant ES can be achieved under low to medium traffic loads while maintaining QoS and fault tolerance.