Research On Multi-path Transmission Scheduling Algorithm In Heterogeneous Network

With the development of networks and mobile devices,more and more applications and technologies,such as live broadcasting,virtual reality,and cloud computing,require greater network bandwidth.At the same time,multi-homed technology enables mobile devices to be equipped with multiple network interfaces,such as mobile devices can simultaneously connect to Wi Fi and 4G cellular networks.Multi-Path TCP(MPTCP)can simultaneously aggregate LTE and WLAN networks,make full use of multiple networks of mobile devices,and ensure the recoverability and reliability of data transmission.However,in an end-to-end network-based model,the wireless link network state between the client and server is usually unpredictable.If the high-speed movement of the equipment affects the signal reception;middleware,such as too many base station equipment,will affect the data transmission.Many reasons lead to unstable network conditions,mainly manifested in packet loss,bandwidth jitter and high delay changes,which ultimately leads to MPTCP arriving out of order when transmitting data packets,affecting throughput.Therefore,the scheduling algorithm of MPTCP is very important,and the link network status needs to be considered to ensure the orderly arrival of data packets as much as possible.This article first explains the relevant knowledge of MPTCP and the existing scheduling algorithm,and analyzes the problems in the transmission process,and uses NS-3 simulation experiments to explain the demonstration.Then through the heterogeneity experiment of three paths and analyze the availability and performance of the existing scheduling algorithm on more than two links;then the existing scheduling algorithm based on round-trip delay is improved,and a transmission capacity and congestion window is proposed,And consider the scheduling algorithm Le Bo of the packet sequence number.The main work of the thesis is as follows:1.This paper analyzes the different types of scheduling algorithms based on RTT.In different scenarios in the real wireless network router environment,we conduct experiments on whether the existing scheduling algorithms are applicable to three paths.In this paper,the variable bandwidth of the path,downloading files,and changing the buffer size of the receiving end in the laboratory controllable environment and the daily environment are observed respectively.Experiments show that ECF and BLEST can effectively reduce the blocking situation,but when the buffer at the receiving end is not affected,using Low RTT can maximize the bandwidth.2.In this paper,after analyzing the shortcomings of the existing scheduling algorithm in the wireless network environment,a Le Bo scheduling algorithm based on the sending capability and congestion window and considering the impact of DSN is proposed,so that the fast subflow can always send data packets from DSN to small,while the slow The stream sends a high-order DSN data packet,and there is no waiting time after the completion of the transmission task during the period,which can effectively use the slow sub-stream bandwidth while ensuring the fast substream bandwidth.Through the NS-3 network simulation platform,a comparative simulation was performed,setting different RTT and receiving end buffer changes,comparing the performance of Low RTT and this algorithm including retransmission time,blocking degree and throughput.Experiments show that Le Bo can effectively reduce the degree of blocking at the receiving end,reduce the number of retransmissions,and increase the overall throughput.The experimental effect is more obvious when the receiving end buffer is limited.