Research On The Improvement Of SCPS-TP Protocol Header Compression Algorithm

The development of space activities and space exploration is rapid,and the ground cable network bandwidth also has an upper limit,So people need to carry out a large amount of data transmission in the form of space in the form of network.The satellite network with its wide coverage,large amount of data transmission has become the focus of attention,especially the integration of space ground network is a hot spot of research.However,compared with the ground wire network,the satellite network has the disadvantages such as large round trip delay,high error rate,asymmetric bandwidth and frequent changes of satellite nodes.So TCP protocols can't work well in the wireless network.So the Space Data Committee is proposing a set of satellite and ground network integrated communication protocol stack SCPS.The SCPS-TP,based on TCP,is used on transport layer,and work much better than TCP protocols.Through in-depth study,SCPS-TP still can improve the performance in some fileds.In this paper,some improvements are made on the SCPS-TP positive and reverse link:Improvement of Vegas congestion algorithm for forward link and improvement of reverse head compression algorithm;Improve the error rate and compression efficiency of the head compression algorithm,the bandwidth is estimated to be combined with Vegas TP,so that Vegas TP is more suitable for satellite networks.For TP's head compression algorithm,the following improvements are made: for the characteristics of high bit error in satellite networks,the data package's header is compressed using the differential packet,Set up link state monitoring,and through the link state to adjust the size of the packet,when the link conditions will be large,when the link condition is poor,and even close down the head compression,Because the head compression in the case of high bit error will not only increase the performance of the system will increase the system additional overhead.The analysis and improvement of SNACK in Baotou are also carried out to find out the redundant field,reduce the average packet length,and then improve the bandwidth utilization.TP-Vegas-B adopts available bandwidth estimation algorithm for bandwidth estimation,the sender continuously monitors the ACK arrival flow,based on estimation of current network available bandwidth.Different from other bandwidth estimationalgorithms,the algorithm does not need to send additional packets to the network.SCPS-RI and NS2 are used to simulate and test the improved protocol.The simulation results show that the improved TP header compression can have high system throughput in high error rate,high round-trip delay.