Optimization And Simulation Of Prophet Routing Algorithm Based On Node Difference

Delay Tolerant Networks(DTN)provides a delay-tolerant network service based on node relay,hosting,and forwarding.It was first used in the Interplanetary Network(IPN)to deal with the intermittent node connection,easy interruption,high bit error rate.However,with the further research and application of DTN in Challenged Networks scenarios such as wildlife tracking networks,battlefield networks,and rural networks,the differences in node performance and status in the network become more apparent,and the data generated by nodes increases and there is a tendency to centralize.The former caused the performance degradation of many classic routing algorithms,and the selected routing nodes were not high-quality,while the latter caused the congestion problem in the challenge network to become more serious.Aiming at these two problems,this paper optimizes the Prophet routing algorithm based on the difference of nodes,and designs a DTN congestion control strategy based on the utility quantification and neighbor agent for the improved algorithm.The main contents are as follows:First of all,this paper designs the improved Prophet routing algorithm Prophet-BSAS based on the difference of nodes for the complex and diversified use environment of nodes.Based on the encounter probability,a consideration is given to the transmission rate of the node,and a node showing a higher rate limit during the transmission process is selected;a consideration of the remaining buffer area of the node is added to select a node with a more abundant remaining buffer area;Considering the average success rate of node transmission,the selected node can effectively avoid the "parking problem" inherent in Prophet routing algorithm.By quantifying the above factors and optimizing the delivery probability formula of Prophet routing algorithm,simulation experiments show that the optimized Prophet-BSAS multiattribute decision routing algorithm has higher message delivery ratio,lower average latency,smaller network overhead ratio,and fewer average hops than Prophet routing algorithm in scenarios where nodes move more randomly or socially.Then,for the Prophet-BSAS routing algorithm,this paper designs a phased and controllable DTN congestion control strategy CUQNA based on utility quantification and neighbor agents.The node congestion state is divided into four states-safe state(SS),normal state(NS),close congestion state(CCS)and congestion state(CS),and congestion control strategies are performed in the CCS and the CS.Screening of messages is performed by quantification of utility,message avoidance is performed in CCS,and buffer is released in CS.At the same time,when the buffer is released,the direct message discarding is reduced by the neighbor agent,and the possible adverse effect of the congestion control strategy on the message delivery ratio is reduced.In the experiment,the value of each weight coefficient in the utility function is determined by the analytic hierarchy process.The final experimental results show that,compared with the classic congestion control strategies such as dropping the earliest message(Drop Front,DF),dropping the last message(Drop Last,DL)and dropping the shortest life time message(Drop Shortest Life Time First,SHLI),CUQNA has higher message delivery ratio,lower average delay and smaller network overhead.Through routing algorithm Prophet-BSAS and congestion control algorithm CUQNA,DTN can provide more efficient,reliable,and low-consumption network services for increasingly complex challenging network environments.