Research On Delay Modeling And Optimization Technology In Time Division Multiplexing Passive Optical Network With Functional Split

Mobile fronthaul(MFH)is a kind of information transmission technology in the Centralized Radio Access Network(C-RAN)architecture,which is responsible for realizing the wireless data transmission between the remote radio unit(RRU)and the baseband unit(BBU).Due to its low cost and high capacity,time division multiplexing passive optical network(TDM-PON)is considered as a feasible solution to accommodate the MFH.However,it is still a critical issue to further reduce the delay of MFH and make optical network meet the Quality of Service(QoS)requirements of wireless services at the same time.In this research,the delay modeling and optimization technology of TDM-PON based MFH is studied,and corresponding work is done in terms of delay model,optimization strategy and network control architecture.Firstly,the direct transmission of data volume in one transmission time interval(TTI)will result in large transmission latency and queuing latency for optical network unit(ONU).In this study,we propose to optimize the delay problem by segmentation of transmitted data into blocks,and we establish controllable delay model of uplink transmission in TDM-PON under different bandwidth allocation mechanisms.The time division multiplexing and time division multiple access of one wavelength channel are abstracted as the queuing model under the polling service,and the mathematic relation and calculation method of the model are elaborated.The simulation results show that segmentation of transmitted data can significantly reduce the latency,and can increase the network scale under the delay constraint condition.Secondly,considering the scheduling order in one polling cycle affects the delay performance of uplink transmitted data in ONU,we propose to obtain the delay sensitive priority of wireless data in ONU through the cooperation between the BBU and optical line terminal(OLT).The priorities of the ONUs will be calculated and mapped based on the bandwidth information and priority information of the wireless services.High-priority ONU can be transmitted without waiting in order to meet the QoS of the delay-sensitive wireless service.The simulation results show that our method can better perceive the wireless services compared with the traditional method and provide differential services according to the delay sensitive priority of the wireless services,which can significantly reduce the average latency of the high-priority ONUs and the delay-sensitive wireless services.