Research On Spray And Wait Routing Algorithm Based On Social Relationship In Mobile Opportunity Network

Different from the traditional Internet usage scenario,Delay Tolerant Network(DTN)is generally used in the more extreme challenging environment.In this case,due to the influence of the node's own factors and external environment,each node does not necessarily have an end-to-end link similar to the traditional Internet,and because of the mobility of nodes,the topology of the whole network presents dynamic changes,making the path in the traditional wireless network Both distance vector routing protocol(DVRP)and link state routing protocol(Isrp)can not be applied to delay tolerant networks.The mobile opportunity network originated from the delay tolerant network,which is generally considered as a wireless ad hoc network with the characteristics of delay tolerant network.It can also be regarded as a DTN routing method,which depends on the chance of meeting between nodes to transmit information.Routing algorithm is the focus and core of opportunistic network technology,and the selection of relay node is one of the key points of routing algorithm.This paper first introduces the concept,characteristics and architecture of mobile opportunity network,and then gives the correlation analysis of some classical routing algorithms in the field of mobile opportunity network.Based on the study of jet waiting routing algorithm,which is one of the classical algorithms,this paper analyzes the characteristics of the two stages of the classical algorithm,combined with the social nodes in the mobile opportunity network Attribute and mobile trajectory,an improved spray waiting routing algorithm based on social relations is proposed.Finally,a large number of experiments are carried out on one simulation platform to evaluate the improved algorithm.Among them,the main improvements are as follows:(1)Aiming at the blindness of Spray and Wait algorithm in selecting relay nodes in the spray phase,a social circle spray strategy based on encounter time interval and encounter probability is proposed.Firstly,the social circle is constructed according to the movement characteristics of the nodes,and the nodes in the whole mobile opportunity network are divided into different social circles.Then,the message delivery mode is divided into the communication within the social circle of the destination node and the communication outside the social circle of the destination node,and the weighted average sum of the average time interval and the number of encounters with the destination node and the destination node are used respectively As the criteria of selecting relay nodes in and out of the loop,the two indexes of the probability of meeting are used to solve the problem of blind selection of relay nodes.(2)Aiming at the limitation of Spray and Wait algorithm to transmit messages in the waiting phase,a social circle waiting strategy based on multi copy strategy is proposed.The details are as follows:different from the waiting stage of S W algorithm,after the social circle is constructed,it is obvious that the nodes in the social circle can be used to have a higher encounter probability.Therefore,this stage can be regarded as another special form of the above-mentioned improved spray stage.However,when the probability of meeting between the node carrying the message and the node it meets to the destination node is relatively small,the multi copy strategy is adopted,that is,according to the buffer occupation of the node The number of nodes carrying the replica message in the whole mobile opportunity network is increased through the multi replica strategy,so as to increase the contact opportunity with the destination node of the replica message.(3)Aiming at the single strategy of Spray and Wait algorithm in the message management of node cache,considering the different attributes of node and message,a cache management scheme based on message scheduling priority is proposed.Specifically,the priority of the message is obtained according to multiple indicators of the message,and the message queue is constructed based on this value.For the weight allocation of each indicator,the analytic hierarchy process commonly used in mathematical modeling is used to solve the problem.After building the message queue of the node,it is mainly used in the following two aspects:the message deletion mechanism is to give priority to deletion when the buffer of the node is insufficient The transmission mechanism of messages is that when delivering messages,messages with high scheduling priority are transmitted first.Finally,based on the one simulation platform,the improved algorithm is used as the experimental group,and other classical algorithms include prophet algorithm,epic algorithm and spray and wait algorithm as the control group.Using different indicators for analysis and comparison,it can be seen that the improved algorithm has a good performance improvement in delivery rate and delay compared with the original algorithm.