The Research Of Cooperative Communications In Safety-approach-oriented Aeronautical Ad Hoc Networks

Intheexistingairtrafccontrolsystem,theaccidentrateishighinapproachphaseand the punctuality rate is low. In order to guarantee the safety, order and efciency ofthe air trafc, the communication, navigation, surveillance and air trafc management(CNS/ATM) system, which is characterized with network integration and informationsharing, has become more and more popular in air trafc control. Aeronautical ad hocnetworks can be adopted to improve the information sharing level between aircrafts,reduce the distance separation between aircrafts to improve the utilization of airspace.At the same time, the stress of the controller can be relieved. Thus, it is in accordancewith the trend of network integration in the CNS/ATM system. However, due to thehigh speed of the aircraft and the complicated channel condition, the aeronautical adhoc networks may sufer from the multipath fadings and the unreliability of the datalink. In this dissertation, from the perspective of guaranteeing the aircraft approachsafety, we develop mechanisms and algorithms in cruise area, terminal area and airportsurface area according to the application of cooperation in the aeronautical ad hocnetworks. Our research is signifcative for both theory and practice in the networkintegration of CNS/ATM. Our work consists of the following main innovations:First, standing on the existing air trafc control system, to guarantee the require-ment of aircraft approach safety, we setup a cooperation based aeronautical ad hocnetworks structure, which consists of the cruise area, terminal area and airport surfacearea. Besides, the channel models in diferent areas are analyzed.Second, in the cruise area, we develop a vertical network model of the single air-wayaccordingtothestandardofthereducedverticalseparationminima(RVSM).Sincethe topology of the network varies rapidly due to the fast speed of the aircraft, we ana-lyze the relationship between the probability of aircraft isolated and the speed, aircraft density and the communication range. Furthermore, the efect of doppler shift on thisprobabilityisinvestigated. Afterthat,fromtheaspectofguaranteeingaircraftapproachsafety, a data transmission mechanism based on network division is designed. Coop-eration is introduced into the subnets and the link connection probability is analyzedin this case.Third, in the terminal area, to satisfy the reliability requirement of the ground-to-air data link in the synthetic vision system(SVS) in aircraft approach, we adopt co-operative communication to eliminate the multipath fadings. With Rician channel,we study the relay selection problem in cooperative communication with probabilis-tic constraint, which avoids the inaccuracy of the channel state information obtainedin the feedback way. Probability approximation and robust optimization are adoptedto transform the problem. Polynomial complexity algorithms are designed to solvethese problems, which efectively improve the reliability of the ground-to-air commu-nication. Since the positions obtained by ADS-B are not realtime and continuous, weformulate the uncertainty of SNR with robust method. The problem of relay selec-tion with probabilistic constraint is further studied. With the expectation and varianceof the channel, we adopt an adjustable parameter to denote the reliability requirement.Heuristic algorithms are designed according to the order of relays obtained by airbornetrace prediction. The infuence to communication reliability caused by discontinuousof position information can be successfully eliminated.Atlast, intheairportsurfacearea, weconsidercooperationintheOFDMAsystemsince the communication link sufers from the multipath fading seriously. UtilizingADS-B technique, the relay selection and subcarrier allocation problem are studiedwith probabilistic constraint. We adopt the K-L divergence to transform the problemas a convex optimization problem. An algorithm which combines interior point cuttingplane method and iteration method is designed to solve this problem. This algorithmefectively improves the reliability of the airport surface communications.