Research On Routing Strategy And Time Delay Optimization Of UAV Ad Hoc Network

With flexible flight and low cost,unmanned aerial vehicles(UAVS)are expected to be widely used in public services such as traffic monitoring and emergency rescue.Limited by the transmission range,formation flight requires the UAV to spontaneously form wireless AD hoc network,that is,the UAV AD hoc network,to provide communication support to each other.Different from the traditional wireless AD hoc network,the UAV AD hoc network has the characteristics of strong mobility,uneven node distribution and changeable topology.Therefore,it is of practical significance to design stable and reliable routing protocols to support inter-machine communication tasks with low delay and high delivery rate in response to the above new challenges.Considering that GPS devices have become the standard configuration of UAV,this paper conducts a targeted research on the routing protocol based on geographical location information represented by GPSR.Aiming at some problems existing in GPSR protocol,a GRDAD routing protocol with distance,position Angle and neighbor node density as routing criteria is obtained.Compared with the traditional GPSR routing protocol,GRDAD protocol has the following four characteristics:1)in the greedy forwarding routing decision-making link,it integrates node mobile information to select next-hop forwarding node,improves the problem of insufficient GPSR routing criteria,and can select a fast and stable transmission path for data packet;2)the link connection time is used to assist the maintenance of neighbor table and solve the failure problem of neighbor node;3)update node position coordinates as required by location prediction algorithm to improve the accuracy of routing decisions;4)when greedy forwarding fails,it shall quickly enter the peripheral forwarding,and use the node to monitor the channel to effectively eliminate redundant paths and hops,so that the data packet can bypass the void area as soon as possible,effectively improve the routing and forwarding efficiency,and reduce the transmission delay.In order to verify the feasibility and applicability of GRDAD protocol,this paper conducted performance tests on the NS2 simulation platform for GPSR,GPSR-R and the improved GRDAD protocol.The results show that:in the high dynamic network environment,the GPSR protocol has advantages in terms of time delay,but the corresponding delivery rate is not ideal.The GPSR-R protocol has a great improvement in delivery rate,but the corresponding delay performance is not ideal.Therefore,GPSR and GPSR-R protocols cannot meet the requirements of low delay and high quality communication of UAV ad-hoc network.However,the GRDAD algorithm takes into account the transmission delay while guaranteeing a certain packet delivery rate,and makes a reasonable compromise and balance between the two,which is in line with the application environment of the UAV ad hoc network.