Design And Verification Of Channel Access Protocol For Uav Swarm Ad-hoc Network

In recent years,various applications based on UAVs have gradually become a research hotspot.Compared with single UAV systems,the multi-UAV systems can perform various tasks more reliably and efficiently,and it is also developing in the direction of miniaturization,clustering and intelligence.The UAV swarm ad hoc network is a dynamic self-organizing network system composed of a large number of low-cost,lightweight,miniaturized and high mobility UAV nodes.Its characteristics of high mobility and dynamic topology change bring great challenges to MAC protocol design.Under the premise of fully considering the characteristics of UAV swarm ad hoc networks,this thesis studies and designs the channel access protocol suitable for UAV swarm ad hoc networks combined with the actual application requirements.The main research contents are as follows:Firstly,this thesis analyzes the characteristics of UAV swarm ad hoc networks and the difficulties in the design of MAC protocols.The current channel access protocols for UAV ad hoc networks are investigated,and the advantages and disadvantages of each MAC protocol are summarized.It is found that the contention-based MAC protocol is difficult to meet the large scale of the network,and the dynamic TDMA protocol is more suitable for UAV swarm ad hoc networks.Secondly,a distributed reliable slot reservation TDMA protocol(RR-TDMA:Reliable Reserved TDMA)suitable for UAV swarm ad hoc networks is proposed.The RR-TDMA protocol divides time slots into service time slots and communication time slots.The dynamic time slot reservation process is completed in the service time slot,and the transmission of data information is completed in the communication time slot,thereby reducing the probability of time slot collision.The RR-TDMA protocol divides the reservation period and non-reservation period,and uses the slot occupancy state table of nodes to effectively avoid the slot conflict within the range of two hops and solve the hidden terminal problem.Thirdly,in order to verify the performance of the protocol,this thesis presents the software implementation scheme of the RR-TDMA protocol in ns-3 simulation platform.On the basis of the simulation implementation,this thesis conducts comparative experiments between the RR-TDMA protocol and the RR-ALOHA protocol in static and dynamic scenarios.The simulation results show that the RR-TDMA protocol is suitable for environments with large node density,fast moving speed and drastic topology changes.Compared with the RR-ALOHA protocol,the RR-TDMA protocol has obvious improvements in throughput,packet loss rate and channel access delay.In this thesis,a distributed dynamic time slot reservation MAC protocol is designed for the UAV swarm ad hoc network,and the protocol is implemented on the ns-3simulation platform and the performance of the protocol is verified.The experimental results show that the RR-TDMA protocol can apply for time slots faster,and the delivery rate of data packets is higher,so that the UAV swarm ad hoc network has better performance.