A Study On OLSR Protocol For Unmanned Aerial Vehicle Ad Hoc Networks

UAV ad hoc networks are developed from traditional mobile ad hoc networks.They are multi-hop,non-centered,and self-organizing.They have better self-adaptation and expansion capabilities than a single drone.As a representative of a priori routing protocol,OLSR(Optimized Link State Routing)protocol is widely used in various aviation ad hoc networks.However,the existing OLSR protocol cannot well adapt to the high-speed movement of the nodes of UAV ad hoc networks,due to the dynamic change of the topology and the high security requirements.In order to meet the performance requirements of UAV ad hoc networks,a routing protocol that can be applied to UAV ad hoc networks is urgently needed.Based on the research of OLSR protocol and the characteristics of UAV ad hoc networks,this paper proposes two improved OLSR protocols for UAV ad hoc networks.The main research contents are as follows:1.In the UAV ad hoc network,nodes move fast,the topology changes quickly,and link interruption is prone to occur during multi-hop communication.Based on the idea of AODV(Ad hoc On-Demand Distance Vector)routing protocol on-demand path finding,an on-demand path finding is proposed,i.e.,reliable OLSR protocol for on-demand pathfinding of drone ad hoc networks(ODR-OLSR).The ODR-OLSR protocol contains three improved mechanisms: First,a neighbor addressing mechanism based on HELLO messages is used to resolve routing loss during the network access phase.To solve the problem of multi-hop link interruption and lack of link maintenance mechanism based on the TC(Topology Control)message-based full-network addressing mechanism,the problem of additional overhead is solved through the dynamic transmission of control messages.The theoretical analysis of the effectiveness of the ODR-OLSR protocol,simulation results show that the protocol can improve the packet sending success rate and throughput without increasing the control overhead.2.Aiming at the problem that the OLSR protocol has no routing mechanism and low channel utilization,a low control overhead optimization routing OLSR protocol for UAV ad hoc networks(LCO-OLSR)is proposed.The LCO-OLSR protocol contains two improved mechanisms: an optimized routing mechanism and an incremental HELLO message mechanism.First of all,the optimization of the routing mechanism is to introduce link stability constraints based on the shortest hop routing criteria,and solves the problem that the OLSR protocol lacks a routing mechanism.Then,the incremental HELLO message mechanism reduces the channel load in high-density scenarios.Simulation experiments show that the LCO-OLSR protocol can significantly reduce the channel load and improve the packet sending success rate in low dynamic scenarios.Finally,the full research work of this thesis is summarized,and the future direction of the OLSR protocol of the UAV ad hoc networks is briefly explained.