Optimization Of OLSR Routing Protocol For High Dynamic And Low Density UAV Self-organizing Network

With the rapid development of science and technology today,due to the continuous decline in the cost of drones,the continuous increase in endurance,and the continuous increase in the complexity of execution,drones have gradually entered the daily lives of the people.UAV cluster business has also begun to develop.UAVs can efficiently perform information collection and simple action operations in wide areas,dangerous areas and dirty areas by using the high maneuverability and airborne nature of UAVs.But because of the high dynamics and low density of this kind of network,there is no routing protocol that can be perfectly adapted.After research and investigation,based on the OLSR routing protocol,this article optimizes the routing protocol for this type of network.In order to more realistically reflect the flight trajectory and flight mode of the UAV cluster when performing tasks,this article investigates a variety of mobile models used for UAV mobile simulation.Based on the UAV movement trajectory of the PPRZM movement model,the PPRZM-O movement model is obtained by optimization and improvement.The model embodies the various possible motion trajectories of the UAV,the unevenness of the information distribution in the mission area,the regionality of the UAV when performing the mission,and the attractiveness of the high-density information area to the UAV.It can more truly reflect the movement characteristics and movement patterns of the UAV when performing tasks.Using PPRZM-O as a mobile model to simulate the OLSR routing protocol,it is found that the performance of the entire network will decrease significantly when the node speed continues to increase in the original OLSR protocol.The MPR set selection algorithm of the original OLSR routing protocol uses the reachability of network nodes as the evaluation index,so that a smaller set of nodes can be obtained,but it also ignores the stability of the link between nodes and the communication quality of the link.,Which has led to a rapid decline in the performance of the entire network when the network nodes are moving at a high speed.In order to solve this problem,this paper changes the judgment index of the MPR set selection algorithm to a comprehensive evaluation index consisting of the movement tendency of the mobile node,the link communication quality between the nodes and the energy margin of the node as the judgment standard.This improves the stability and communication quality of the entire MPR network topology.The PPRZM-O is used as a mobile model and compared with the original OLSR routing protocol.It is found that the OLSR-O routing protocol is superior to the original OLSR routing protocol in all aspects of network performance except for the routing overhead.In order to reduce the overhead of the OLSR-O routing protocol in terms of control information.This paper reduces the redundancy of the MPR set through secondary screening,and regulates the sending interval of HELLO messages in real time by monitoring the network,so as to reduce the frequency of sending HELLO messages when the local network is stable.From this we have obtained the routing protocol OLSR-OH,which also uses PPRZM-O as a mobile model.Compared with the original OLSR protocol and OLSR-O routing protocol,we find that while the routing overhead of OLSROH is significantly reduced,its other network performance is comparable.Compared with OLSR-O,there is no significant decrease.Finally,this paper transplants the improved routing protocol to the Linux system,and builds the entire UAV self-organizing network,which realizes the self-organizing network communication of the UAV and the collection of network information on the ground.Thus,the topology of the entire UAV network can be displayed on the ground side,and flight instructions can be transmitted from the ground side to realize the flight control of the UAV.