Research On Mobility Management In IP/LEO Satellite Network

In recent years,low-orbit satellite communication system have developed rapidly because of their low orbit,low delay,and low information loss.The next generation mobile communication network is considered to be an IP based network.The development of satellite communication technology provides basic technical support for next-generation IP wireless network.Access to the Internet via IP/LEO satellite network has become one of the main directions for satellite communications and the next generation of all-IP wireless network.In the IP/LEO satellite network,because of the high-speed movement of the satellite relative to the ground,the network needs to track the network of the terminal and obtain the location of the terminal in the system to ensure that the user receives high-quality services.This brings a key technical issue of IP/LEO satellite communication system,which is mobility management.The research in this paper is mainly aimed at the location management problem in mobility management technology.With the development of network technology,the number of users and the volume of business are rapidly increasing.Many application scenarios of low-orbit satellites are application scenarios of dense users.For mobility management process in the low-orbit satellite communication system with dense users,there is still a problem: when many terrestrial users are densely covered within a certain range,a situation that a large number of users will be triggered by the broadcast of the new satellite and simultaneously send a mobility management request to the satellite could happen.For satellite communication systems with limited resources,simultaneous mobility management services are bound to cause competition and conflicts on limited access resources.Moreover,in a large number of user scenarios,the amount of users is large;and the low-orbit satellites run at a high speed,resulting in fast switching speeds.users require frequent location update,resulting in a large number of request messages and causing the network throughput to drop rapidly,which will greatly affect network performance.In response to these problems,this paper studies the mobility management technology in IP/LEO satellite networks.The specific work is as follows:(1)Firstly,we will briefly introduce the definition,development,classification,IP/LEO network architecture,typical system and some key technologies of the satellite communication system and the concept of mobility management in IP/LEO satellite network is highlighted.This paper mainly focuses on the location management of mobility management.(2)For the dense user mobility management scenario,Users send a mobility management request message to the satellite at the same time because of receiving a broadcast message,causing a contention conflict,and for the broadcast,system have a fixed broadcast overhead,there is an optimal number of users to make the average cost is minimal.By controlling the length of the broadcast period to be optimal,the number of users is controlled optimally to obtain optimal performance.At the same time,because the number of accumulated users requiring mobility management requests in a broadcast period is related to the user density,and the density cannot be obtained,a broadcast period adaptive adjustment method based on pseudo-Bayesian algorithm is proposed.By estimating the current number of users and calculating the density,the next optimal broadcast period is obtained,so that the broadcast period is adaptively changed with the user density,so that the average overhead is the lowest.(3)Research has been conducted on the problem of network performance degradation caused by bursty location management signaling in dense user scenarios.Firstly,it is pointed out that the existing location management strategies are to change the location update signaling that needs to be transmitted to the home agent according to the traditional location management strategy,and become a localized signaling transmission to avoid frequent location update with the home agent.Finally,a group location management strategy from the perspective of reducing the number of signaling is proposed.The management process of group location management strategy is introduced in detail.A group location management strategy based on ground station is proposed,which combines the group location management strategy with the existing ground station-based location management strategy.Through simulation and performance analysis,the group location management strategy can effectively reduce the signaling overhead of location management.