Research And Optimization Of OLSR Protocol In Fanets

With the development and popularization of UAVs(Unmanned Aerial Vehicle,UAV),their applications have gradually entered various fields of society and life,and FANETs(Flying Ad hoc Networks,FANETs)has also received more and more attention.The routing protocol,which has always been a key technology for mobile ad hoc networks,is also important in FANETs.However,the rapid changes in the network topology brought about by the high mobility of UAV nodes make the network performance of FANETs more vulnerable.Therefore,the routing protocol in the traditional self-organizing network cannot be well applied to the FANETs.In addition,energy constraints and other factors also pose greater challenges to FANETs routing technology.Therefore,based on the network characteristics of FANETs,this paper mainly studies and optimizes the OLSR(Optimized Link State Routing,OLSR)protocol in a planar topology to improve its performance,making it more suitable for FANETs.The main work of this paper is as follows:First,for the problem of frequent network topology changes caused by the high mobility of UAV nodes,comprehensively considering the link transmission quality and link stability between nodes,an optimized MPR(Multi Point Relay,MPR)set selection algorithm based on node link transmission quality and mobile similarity is proposed,and the weighted comprehensive link evaluation index replaces node connection degree as the MPR set selection criterion.Under the NS-2 simulator,a comparative analysis of PDR,end-to-end delay,and routing control overhead was performed,which verifies the performance improvement of the proposed algorithm in terms of packet delivery rate and average end-to-end delay.Secondly,in view of the adverse effects of the fixed routing packet transmission interval of the OLSR protocol under different network conditions and the problem of increased routing overhead caused by optimizing the MPR set selection algorithm,this paper proposes an adaptive routing control packet transmission optimization algorithm.By monitoring the network topology changes,the transmission interval of HELLO messages and TC packet is adjusted adaptively to reduce the routing control overhead under the premise of ensuring network transmission performance as much as possible.Furthermore,this routing packet transmission optimization algorithm is applied on the basis of optimizing the MPR set selection algorithm,and simulation experiments are conducted with NS-2,which verifies that the proposed algorithm can effectively reduce the routing control overhead and improve the packet delivery rate.Finally,this paper carried out the hardware implementation of the UAVs Ad hoc network system based on the OLSR protocol.Using DJI Matrice 100 drone and Raspberry Pi 3B+,combined with DJI Onboard SDK and ROS system,an ad hoc network with one computer as ground station and two UAV nodes is realized.