Key Technologies Of Satellite-ground Integrated Broadband Connectivity For Civil Aviation Communications

With the development of the civil aviation industry and the increase of air passenger traffic,the demand for aviation communication services and in-flight passenger services has grown rapidly,and it is imperative to carry out relevant research work on the next generation of civil aviation communication networks.Benefit from the characteristics of low cost and low latency,high-frequency air to ground communication will dominate the aviation communication network in the future.However,the highfrequency air to ground communication system still has the problems of insufficient mobility support for the aircrafts,low transmission reliability and efficiency,and the inability to independently provide seamless communication services for the aircrafts.In this context,this thesis aims to assist the air to ground communication system with the help of satellite communication to provide high-capacity and seamless communication services for civil aircrafts.In order to improve the air to ground system’s mobility support for aircrafts,this thesis proposes a civil aviation communication network architecture based on controldata plane separation.The architecture utilizes a relatively stable satellite network to transmit the control plane data of the air to ground communication system and provide data plane services for the aircraft when the air to ground communication resources are insufficient.The architecture realizes the separation of the control plane and data plane handover process of air to ground communication.Further,this thesis demonstrates the superiority of the proposed architecture by comparing the handover delay between the proposed architecture and the traditional one.In order to solve the problems of low transmission reliability and efficiency of existing beam adjustment methods in high-frequency air to ground communication systems,this thesis proposes a satellite-guided beam adjustment scheme.The proposed scheme uses satellite channels to transmit aircraft position information and beam adjustment control signaling,so that the ground base station generates the widest possible transmission beam to extend the service time of each transmission beam,thereby reducing the frequency of transmission beam adjustment,and in each transmission beam,the aircraft autonomously adjusts the receiving beam angle and width,thereby reducing the feedback overhead and stabilizing the receiving signal-to-noise ratio.Even if the air to ground connection is interrupted due to misalignment of the beam,the aircraft can still re-establish the air-ground connection by transmitting control information through the satellite channel.Finally,the effectiveness of the proposed scheme is proved by simulation experiments.In order to solve the problem of on-demand allocation of communication resources in a dynamic network environment when satellite-ground networks coordinate to provide data services for aircraft,this thesis proposes a joint resource allocation scheme for satellite-ground coordinated civil aviation communication network.The scheme first proposes a resource allocation model that differentiates service priorities.In the dynamic civil aviation communication network,the transmission performance requirements of safety data services are guaranteed first,while the transmission performance of non-safety data services is maximized,and the benefits and costs of service handover between different networks is balanced.Subsequently,a resource allocation algorithm based on Q-learning is proposed,which distributes different services to appropriate networks and allocates corresponding channel resources,so as to solve the above problems in a low-complexity manner,which is suitable for high mobility scenarios of civil aviation.Finally,the effectiveness of the proposed scheme is proved by simulation experiments.