Research On Gateway Selection And Handoff Mechanism For UAV Ad Hoc Networks

With the rapid development of unmanned aerial vehicle(UAV)technology,the UAV ad hoc Network,which is composed of UAV nodes according to different application requirements,has become a hot research topic at present.UAV has a wide application prospect.For example,in the military,including border surveillance and firepower attack,and in the civilian aspects,including disaster monitoring,remote sensing and so on.Moreover,according to the application of UAV ad hoc network,UAV network and ground control station(GCS)has a lot of communication requirements.Therefore,in order to meet the need of communication between UAV ad hoc network and GCS,the research of UAV ad hoc network gateway becomes particularly important.This thesis summarizes the existing UAV distributed gateway selection algorithms,mobile ad hoc network cluster head selection and handoff mechanism.In this thesis,the gateway selection and handoff of UAV ad hoc network are studied deeply and some improvements are put forward.The specific research work in the above two aspects is as follows:Firstly,for improving large delay of data transmission and low rate of data success transmishort duration of the gateway node when the UAV ad hoc networks communicates with theGCS,a gateway selection algorithm based on UAV-GCS link state prediction is proposed.The proposed algorithm selects the nodes with longer time connection with the GCS by establishing the prediction based on the UAV activity model and motion trend.Through the HELLO message conditional forwarding mechanism,the candidate gateway node can obtain the information of the two-hop neighbor nodes in time,which improves the accuracy of the stability calculation of the two-hop neighbor nodes.By using the function timing mechanism to make the gateway select the node with the largest parameter as the gateway,the unnecessary gateway handoff caused by the random delay mechanism in the distributed gateway selection algorithm is effectively avoided.The simulation results show that the proposed algorithm effectively extends the working time of gateway nodes and has the advantages of longer average duration of the gateway node,smaller data transmission delay and higher rate of data success transmission.Secondly,in order to reduce the adverse effect of sudden failure of gateway nodes on UAV ad hoc network and improve the reliability of the network,an efficient and fast handoff algorithm for UAV ad hoc network gateway is proposed in this thesis.Firstly,the selection mechanism of backup gateway is designed,and the backup gateway node is selected by considering the distance between gateway node and neighbor node.Secondly,the mechanism of gateway failure identification is improved,and the backup gateway can detect the failure of gateway node more quickly.Finally,an efficient and fast handoff mechanism of UAV ad hoc gateway is proposed,which reduces the failure time of gateway.Simulation results show that the proposed algorithm can be reduced.The failure time of UAV ad hoc gateway improves the reliability of UAV network and improves the performance of delay and throughput.Finally,the work done in this thesis is summarized,and the further research of UAV ad hoc Gateway is prospected.