Design And Implementaion Of Control Server Of Air-ground Communication System In Low-Altitude Airspace Based On LTE

With the rapid development of Chinese economy,the huge demands of commercial flight activity stimulate the implementation of Chinese opening up strategy of low level.China has planned to open the low level air in 2013.Then,the increasing commercial flight activity would pose serious challenges to Chinese air traffic control.LTE(Long Term Evolution)is a long term evolution of the 3G technology which proposed by the 3GPP in 2004.Introduced LTE network into the air grid,which can not only reduce the complexity of network deployment greatly,but also provide a range of services for all types of low-altitude aircraft with the LTE broadband data link networks.This paper aims to realize the control function of voice services in air traffic control with the VoIP technology.For compatible with current management model of VHF voice communications,we need import the control server and improve VoIP technology to the ground network of the air-ground communication system.This paper studies the background firstly,then discusses the challenges that ATN faced,analyzes the disadvantages of the VHF in the voice service,and finally leads out the goal of this paper.In the main part of this paper,it firstly introduces the technology the Control Server uses.The Control Server uses the SIP as the control protocol,and uses the SIP message of the format MSML to control the Media Server.Then,the paper analyzes deeply the position the Control Server and draw a conclusion the main functions of the Control Server are managing the terminal and controlling the air-ground communication.At last of this part,it designs the control model and the determine algorithms of sector.In the main design part,the core of the paper is to design the software interfaces and communications processes based on the sector management and voice control,then in the part of the implementation section and the detailed design section,the paper designs the database tables,class diagrams and SDL flowchart,with the middleware Uniframe.Finally,we.test the control server with the test tools and get the test results.At the end of the paper,it summaries the work and makes a plan of the work in the future.