Design And Implementation Of Path Selection Module In Air-Ground Broadband Link

With the development of domestically-produced airplanes,the increasing demand for Internet access by airplane passengers has made people have new requirements for air-to-ground data exchange systems.Air-to-ground broadband communication technology is a necessary technology for data exchange between airborne networks and the ground.At present,the main communication scenarios in the civil aviation system are air-to-ground communication links,airborne wireless local area networks,and satellite communication links.Because various communication links,especially terrestrial communication links,are affected by base station electromagnetics,etc.,the link state fluctuates greatly or even shut down.Therefore,in order to guarantee the service quality of the data exchange system,it is necessary to develop a route selection module for domestic aircraft to dynamically select the optimal communication link for customers on the aircraft.First of all,based on the above background,this thesis analyzes the current status of air-to-ground broadband communication and network selection algorithms at home and abroad,especially the current research status of multi-attribute decision-making algorithms.Then according to the requirements in the project book,the functional and non-functional requirements of the project were analyzed,and the overall design of the path selection module was carried out.Then,in order to solve the problem of dynamic path selection in passenger plane broadband communication,a path selection algorithm based on firewall strategy is designed,and the path selection module is implemented.This thesis first conducts a detailed research on the firewall and policy routing technology involved in the Linux system,combines iptables and Linux advanced routing,designs a firewall-based policy path selection algorithm,and divides the entire path selection algorithm into the basic data layer,perception layer and decision layer.The basic data layer provides the basic data required by the algorithm.The perception layer is used to provide the decision layer with the status information of each data stream and candidate link.The decision layer is based on this information for the client requesting access.Find the most reasonable forwarding path and congestion control.Finally,through the test,all the requirements in the project were completed.Finally,in view of the limitations of multi-service processing in the path selection module,this thesis conducts research on related multi-attribute decision-making techniques,designs a multi-link importance ranking algorithm based on service characteristics and user preferences,and introduces utility functions for different business flows,quantify the satisfaction of different service flows to link attributes,then construct active and passive comprehensive weights of attributes through fuzzy analytic hierarchy process and entropy weight method,and finally combine the user preference value to obtain the comprehensive score of the candidate link.The simulation results show that the algorithm can sort links reasonably according to service characteristics and user preferences,and effectively reduces the abnormal rate of sorting.