Research On Congestion Control Algorithm Of DTN Network Based On High Altitude Platform

Compared with terrestrial cellular communication network,near space communication based on high altitude platform has the characteristics of large coverage,flexible deployment,easy maintenance and so on.Compared with satellite communication network,it has the advantages of low cost,small delay and small path attenuation.However,the sparsity and mobility of the nodes of the upper platform network can not lead to a stable topology network.The nodes can not guarantee a stable communication link,so the traditional TCP/IP protocol can not meet the requirements.The use of Delay Tolerant Network(DTN)to achieve high altitude platform communication is a solution at present.This thesis analyzes and summarizes the problems in the routing protocol and congestion control strategy in the DTN network based on the requirements of the National Natural Science Foundation's major research project "Analysis and Optimization on Network Capacity of Near Space Communication Network with Dynamic Topology",and proposes a multi copy routing and efficient congestion control strategy suitable for high altitude platform communication.The main work of this thesis is as follows:(1)A Prophet routing protocol PMNC(improved Prophet based on Message Number and Congestion)based on congestion and message number improvement is proposed.On the basis of the Prophet protocol determining that the message forwarding mode is insufficient,the node meeting probability is limited by the number of copy duty of the message and the remaining survival time of the message.The purpose of increasing delivery success rate and reducing network cost is achieved by increasing the purpose of message dissemination.(2)A multi parameter joint congestion control strategy,MPCC(Multiparameter Congestion Control),is proposed.Message weight is defined based on the message feature of the copy duty and the remaining survival time combined with the node encounter probability and it can be the basis of packet loss by redundant message to reduce the probability of the buffer size occupied and the possibility of congestion?(3)Simulate the PMNC routing protocol and MPCC congestion control strategy through the THE ONE simulator.The simulation results of network performance indexes such as network overhead and delivery success rate are compared with other routing protocols and congestion control strategies,and the feasibility of the proposed routing protocol and congestion control strategy is proved.