Routing Algorithms Based On Social Attributes Of Nodes In Delay Tolerant Networks

Delay Tolerant Network is a new form of distributed Ad-Hoc network,which breaks through the limitation of the traditional network on the all-connected communication links.DTN uses the "store-carry-forward" routing mechanism to forward messages hop-by-hop.And it uses the intermittent links brought by nodes' movement to realize network communication.Compared with the traditional network,DTN has the characteristics of frequent link interruption,weak node storage capacity,prolonged transmission time,and so on,which cause the traditional routing mechanism can not be applied in DTN.But the routing algorithm has a vital impact on the performance of the network.Therefore,the research of DTN routing algorithm has became one of the research hotspots in recent years.In this paper,we first introduce the background and network characteristics of DTN,typical applications and development status of DTN.The routing algorithms in DTN are summarized,and the routing algorithms based on social attributes of nodes are analyzed emphatically.Furthermore,the main ideas of some typical algorithms are clearly described,and their advantages and disadvantages are also analyzed.Secondly,after analysis of the potential social association between nodes,we propose a novel routing protocol based on community division,vitality and energy balance(RCVE)for DTN,which makes use of the positive influence of node social attributes on the routing algorithm.RCVE simultaneously considers the physical and social attr:ibutes of nodes,in which a new community division method is presented.In order to enhance information sharing among community nodes,the dynamic community detection and division model is carried out through the double selection of the node friendship and the similarity,in which the multi-dimensional friendship between nodes is dynamically adjusted by the contact time,the contact frequency and the contact rule.On this basis,with a joint consideration of vitality and energy balance,RCVE always select a node with high vitality and balanced energy level for message relaying to avoid excessive consumption of optimal nodes with high vitality,and prolong their time to participate in relay service.By means of effective community division method,balanced routing strategy,and replica control strategy when the node cache is insufficient,PRPF improves the message delivery ratio,reduces the average overhead,the average delay and the average hop count.Thirdly,in view of the negative social attributes such as selfishness for nodes,we propose a probabilistic routing based on reward and penalty mechanism and forwarding ability of nodes(PRPF)for DTN.In PRPF,the forwarding ability of the nodes is introduced to reflect the relay ability of the nodes and indirectly reflect nodes' selfishness,which takes the quantities of messages successfully forwarded and discarded by nodes into account.In addition,the predictive delivery probability to the destination node is predicted and calculated more accurately,in such manner that the historical delivery probability,the forwarding ability and the resource condition of relay nodes are considered.Meanwhile,in order to reduce the misdirection of high-frequency contact of nodes in short-term to predict the probability of delivery,time-effectiveness control is strengthened to reduce the number of copies forwarded.Moreover,the transitive information is screened according to the energy level of nodes to improve the efficiency of routing.Furthermore,based on the predicted delivery probability,the concept of message value is introduced,which is influenced by such factors as message remaining survival time and message size.And the messages cached in nodes are sorted according to the message value,and the message with high value is forwarded first.When the buffer space is insufficient,the message with lower value is deleted first.The proposed algorithm is motivated by improving the predictive delivery probability of nodes and punished selfish nodes by reducing the forwarding ability and message value.The relay node with high predictive delivery probability and high node forwarding ability is preferred to select as the message forwarder in the proposed algorithm.It is beneficial to improve the average message delivery ratio and reduee the average network oVerhead and message average delay.Finally,the performances of the proposed algorithm are verified through a series of simulation experiments,based on the Opportunistic Network Environment(ONE)simulation platform,and are compared with the existing algorithms in the paper to verify their validity.