Research On Energy-Saving Mechanism Of Integrated Fiber-Wireless Access Networks Based On Frame Aggregation

Integrated fiber-wireless access network(FiWi)takes advantages of both optical access network and wireless access network such as high bandwidth,high reliability,supports high mobility and flexibility,has become one of the important solutions in next generation of broadband access network.Statistics show that the energy consumption of access network accounts for about 70% of the energy consumption of the entire communication network,and the proportion will continue to increase as the number of communication devices increases and the bandwidth rate increases.Thus,an effective energy-saving mechanism for access networks will play an important role in reducing the energy consumption of the whole network.FiWi has the problems of low utilization rate of optical network unit and large control overhead during data transmission.How to reduce the energy consumption of the network on the basis of ensuring network performance is a major issue in FiWi.Firstly,the architecture and key technologies of FiWi is introduced,and the existing energy-saving mechanisms of the network is analyzed,such as hardware and software energy-saving mechanisms and energy-saving mechanisms based on frame aggregation in FiWi,and then the details of the existing energy-saving strategies is described.Secondly,an energy-saving mechanism with uplink data frame aggregation is proposed,the M/G/1 model is used to analyze the queue delay of the data frame on the wireless nodes and the optical nodes,by combining with the maximum tolerable delay of different priority,the optimal length of the aggregation frame is deduced in different network conditions.And then according to the optimal frame length to perform sleep scheduling for optical backhaul nodes,on the premise of guaranteeing the service delay,as much as possible to extend the length of node sleep time to improve the network energy efficiency.The simulation results show that the proposed method can effectively reduce the energy consumption of the whole network and guarantee the delay performance.Thirdly,an adaptive data frame aggregation energy-saving mechanism with load transfer is proposed.The quality of the wireless channel is assessed,then adaptively adjusts the aggregated frame length according to the channel quality to reduce the energy consumption caused by frequent preemption and access to the channel and the retransmission of large number of data frames due to poor channel quality.According to the delay requirements of different priority services,the optical backhaul defines the optimal length for each priority queue,and then the load transfer mechanism is used to dynamically distribute traffic load among different ONUs to maximize sleep rate of ONU and reduce network energy consumption.The simulation results show that the proposed method can greatly reduce the network energy consumption while guaranteeing the delay performance of various services.Lastly,the article is summarised and the outlook is presented.