Research And Implementation Of Satellite-Terrestrial Integrated Network Handover System Based On Multi-Attribute Decision

With the development of terrestrial mobile communications and satellite communications,the Satellite-Terrestrial integrated network has gradually become a research hotspot.The Satellite-Terrestrial integrated network can make up for the deficiency of their respective communication capabilities and provide communication services for users.With the continuous expansion of satellite network scale,the number of low-orbit satellites is increasing year by year,and the coverage area of satellites is better and the communication delay is reduced.Due to the low orbit altitude and fast operation speed of low-orbit satellites,the topology of Satellite-Terrestrial integrated network changes,which brings new challenges to the mobility management of the whole network.In order to ensure the continuity of the user’s business,it is necessary to switch the service satellite between the user and the gateway station frequently.At present,for the handover mechanism of feeder link between.satellite and earth,the existing research on feeder link mainly focuses on the design of network routing method and data control separation,and the multiple attributes and user characteristics of the link between satellite and ground are not fully considered.Therefore,it is of great significance for the development of the Satellite-Terrestrial integrated network to study the reasonable and effective handover method according to the user group characteristics of the current feeder link and the connection state of the Satellite-Terrestrial integrated network.This paper summarizes the main methods of handover research in Satellite-Terrestrial integrated network,analyzes the important factors in the handover problem of feeder link.Aiming at the signaling storm caused by too many users when feeder link handover occurs,a multi-attribute feeder link handover decision method based on user clustering and group pre-switching is proposed.Due to the high-speed movement of low-orbit satellites,the feeder link between the satellite and the earth is constantly changed,and all users of the link need to be switched for each change.Firstly,fuzzy clustering of users is carried out,and users are grouped according to their location information,connection status and service type attributes.The user clustering center is used as user characteristics to form subjective weights.Secondly,the objective weight is taken into account the signal strength,the number of remaining channels and the available service time.Finally,the optimal target satellite is selected for handover by using the deviation maximization method to comprehensively consider the subjective and objective weights,and construct the final multi-attribute weights.This method not only considers the status attribute of the link between the satellite and the earth,but also starts from the attribute characteristics of the users to cluster and group the users.The pre-handover method is adopted to ensure the business requirements of the users and reduce the scale of switching users at the same time.In addition,the paper designs and develops the Satellite-Terrestrial integrated network feeder link handover management system,realizes the link state management,handover decision,network management,visual display and other functional modules.The system is tested by the joint satellite-based fusion network simulation platform,and the results show that the system can reduce the number of user switching and ensure the stability of service delay.