Research On Energy-saving Mechanism With Load Transfer In Hybrid Optical Wireless Broadband Access Network

Hybrid Optical-Wireless Broadband Access Network(HOWBAN)which possess advantages of both optical access network and wireless access network such as low loss,high bandwidth,support mobility and flexibility,has become one of the important solutions in next generation of broadband access technology.In addition,the existance of many active devices in access network lead to 70% of total energy consumption in the entire communications network approximately and its ratio will continue to grow over the next few decades.Thus,an effective energy saving mechanism for access networks will plays an important role in reducing the energy consumption of the whole network.In HOWBAN,combining the characteristics of the optical domain with wireless domain to make node sleep can reduce network energy consumption effectively,but the wireless node sleep will effect the user access and network connection.At the same time,there are still some active Optical Network Unit(ONU)with low utilization in the hybrid network.Therefore,how to choose the sleep node according to the correlation of different inter-domain nodes with load transfer and combine the modular sleep mechanism in activate ONU to optimal the energy efficiency is an important problem of HOWBAN.Firstly,this paper summarizes the HOWBAN and introduces the key technology of the network in detail.Hereafter,this paper analyzes the energy-saving mechanism such as hardware energy-saving mechanism,software energy-saving mechanism and energy-saving mechanism with load transfer in HOWBAN,then elaborates the existing typical energy-saving strategy.Finally,the contents of the chapter is summarized.Secondly,a collaborative sleep mechanism between cross-domain nodes with load transfer in HOWBAN is proposed.By analyzing the current load of ONU and the correlation between ONU and wireless router,the mechanism select the sleep node.In order to determine the destionation of load transfer,the maximum matching theory is used.Thus,it can reducing the network energy consumption on the basis of guaranteeing network connectivity and low service delay.The simulation results show that the algorithm proposed can reduce the energy consumption of the whole network without affecting the packet delay significantly.Thirdly,an ONU status listen and modular sleep mechanism with load transfer is proposed.The algorithm add the listening state to state switching between ONU's sleep state and ONU's active state and monitor the network load for multiple polling cycles,then combine the dynamic bandwidth allocation algorithm to make ONU go to modular sleep so as to save network energy consumption on the basis of keeping low packet delay.The results show that the proposed algorithm can reduce the energy consumption of HOWBAN and ensure the low packet delay.Lastly,the article is summarised and the outlook is presented.