Research On The Network Coding Based MPTCP In Wireless Mesh Networks

As a new type of high capacity and high speed network, wireless mesh network has been widely usedin all areas of people’s daily life such as broadband home network, transportation systems, buildingautomation and monitoring systems. As the main technology of wireless mesh network, multipathtransmission and network coding can greatly improve the throughput of the system and increase thestability of the system. However, the instability of the wireless link greatly reduces the performance ofmultipath transmission. This brings huge challenges to the study of the multipath transmission.This thesis is centered on the studies of network coding technology and the related technologies ofmultipath transmission, and it further analysis the reasons why the system is unstable，and the networktransmission efficiency and the system throughput are so lower when using multipath transmission. Then itputs forward the corresponding solutions. The specific contents of the research can be briefly described asfollows:1. In view of the network coding has serious delay effect on the TCP transport, we put forward a kindof transmission mode that combines the multipath with network coding technology, namely combines themultipath transmission in wireless mesh network with the network coding, and then triggers an improvedcongestion control mechanism, and adopts a binding credit algorithm that is used to control thetransmission speed of wireless node, which improves the system throughput and increases the stability ofthe transmission in wireless mesh networks. Finally, this thesis adopts a simple and efficient algorithm toestimate packet loss rate in the transmission scheme, which can control the rate of sending coded data,reduce the TCP timeout retransmission, and reduce the decoding delay of the destination nodes.2. In the traditional parallel multipath transmission, the end-to-end delay difference amongtransmission paths is so large, so we put forward an adaptive multipath transmission congestion controlscheme, which controls the congestion window of the flow of each TCP in real time, and makes thetransmission delay difference between each blade flow of multiple link become minimum. As a result it cangreatly increase the effective throughput of multipath transmission, and minimize the needed cache for thesink nodes.3. When we use the multipath transmission, the receive buffer will produce a serious congestionproblem. So we put forward a new data scheduling scheme, which uses two send queue to assign packetreasonably to each note in the flow, at the same time, we adjust the number of send window according tothe stand or fall of the sub-flow properties. As a result it can greatly reduce the congestion of the receivingbuffer, and improve the throughput and bandwidth availability ratio of the network.