Research On Opportunistic Transmission Control Methods For Weak Connection Problems On An Apron

As the core area of civil aviation airport transportation operations,apron-aware information is driven by flight flow.Apron-aware networks presents the characteristics of large number and dispersion of nodes,strong data heterogeneity,and dynamic change of network topology.It is easy to cause unbalanced network load,rapid consumption of node resources,and the network presents problems such as disconnection and weak connectivity.In order to improve the weak connection environment of the apron-aware network,based on the opportunistic network theory,this paper researches three problems: optimizing the unconnected subdomain WSN to improve the quality of opportunistic network access,studying the opportunistic network transmission routing control strategy,and solving the network congestion problem during the opportunistic transmissions.The thesis provides theoretical support and technical reference for the establishment of apron-aware networks,and is also the theoretical and technological innovation of opportunistic transmission control in civil aviation applications.Firstly,for the problems of the information source of opportunistic transmission,namely the network quality problem of unconnected subdomain WSN,the thesis proposes improved Ant colony optimization for clustering routing algorithm(A-LEACH)in the stable phase of the LEACH,considering the active equipment with better performance can be used as a fixed cluster head in the apron environment.The method realizes the load balance and improves WSN quality to lay the foundation for access to the opportunity network,by adjusting the WSN node density to optimize the the network topology and applying ACO to solve the problem of single path of cluster head convergence.The simulation results show that the algorithm studied in this paper improves the node packet transmission volume by about 40% and the network life cycle by about 17%,so there is superiority in balancing network energy consumption.Secondly,for the weak connection phenomenon of the information link between the apron unconnected subdomains,considering the apron environment and the operating characteristics of special vehicles,based on mobile agent(M-Agent)an opportunistic transmission control method is studied.By completing the classification model design of the apron-aware data stream and optimizing the load balance for data aggregation issues,the M-Agent is realized and complete the "storage-carry-forward" of information between unconnected subdomains.ONE simulation shows that the method improves the message delivery rate by up to 20.6%,reduces network overhead by up to 48.79% and reduces communication delay by approximately 12.31%,in terms of number of nodes and cache capacity,by comparing with the classic algorithms such as Epidemic and Prophet.Finally,in view of the problems of large number of copies,data redundancy and network congestion in the process of opportunistic transmission,an apron cache control strategy(ACER)based on cell evolution rule is studied.Based on establishing a data communication model based on node congestion,cache control strategy is studied with neighbor node copy holdings by introducing cellular automata model.ONE simulation shows that the strategy can increase the message delivery rate by about 42% and reduce the network overhead by about 62%,by comparing with the traditional opportunistic network cache management strategies DL and DY.