Research On MPTCP Technology In Aerospace Heterogeneous Network

With the rapid development of mobile networks and next-generation communication systems,satellite networks have become one of the most important parts of global communication system.The application of multipath transmission control protocol(MPTCP)technology promotes convergence of aerospace heterogeneous networks and improvement of transmission efficiency greatly in complex environment.However,satellite network has the characteristics of high delay,high error rate and large path heterogeneity,which makes throughput performance not good and bandwidth utilization of existing congestion control scheme and data-scheduling strategy relatively low.In this thesis,the following two researches are mainly carried out for the issues mentioned above:Firstly,based on the characteristics of high bandwidth-delay product(BDP)and periodically changed packet loss rate in the highy lossy satellite network,this thesis proposes a bandwidth and round-trip time detection based congestion control algorithm(BWRD)for MPTCP combined with the idea of bottleneck bandwidth detection and packet loss reason.While retaining window increase rule and links fairness of Linked Increase Algorithm(LIA),the algorithm no longer simply uses packet loss as a sign of network congestion,but analyzes whether the link's bottleneck bandwidth is reached at this time.Therefore,it can determine the reason of packet loss correctly and control the reduction of congestion window reasonably.The experimental results show that the total throughput performance of BWRD algorithm is 155.2%higher than that of the LIA algorithm at the same simulation time,and the total throughput performance of Uncoupled TCP algorithm with unfairness is also improved by 91.8%.When transferring files of the same size,the transmission time of BWRD algorithm is 57.4%shorter than that of the LIA algorithm,and the transmission time of Uncoupled TCP algorithm is shortened by 43.6%.Afterwards,based on the characteristics of large path heterogeneity in satellite networks,this thesis proposes an weighted network state assessment based data scheduling algorithm(WNSA)for MPTCP combined with the idea of link's bottleneck bandwidth and packet loss rate detection.The algorithm no longer uses delay as the sole data-scheduling basis.Instead,it calculates performance score of link's bottleneck bandwidth,packet loss rate by weighting and comprehensively evaluates the actual load status of current link to schedule data properly.The experimental results show that the total throughput of WNSA algorithm is 22.8%higher than that of Low-RTT algorithm and 3.1%higher than Round Robin algorithm.When transferring files of the same size,the total transmission time of the WNSA algorithm is reduced by 22.2%compared to the Low-RTT algorithm,and by 3.2%to the Round Robin algorithm.