The Social Routing Protocol In Delay Tolerant Networks Based On Relative Distance Closeness Degree

Due to flexible networking features and high rate of fault tolerance, Delay/Disruption Tolerant Network (DTN) has a very broad application prospects inInterplanetary Networking communications, mobile vehicle network, militarybattlefield communications, disaster relief and many other fields.In social-based DTN network, a mobile node is usually carried and controlled byhuman, thus showing a certain social characteristics. In the current social DTNrouting protocols, the data are converging to the minority of higher social metricsnodes, which causes the extreme imbalance in network resource consumption,forming a so-called “hot spot problem”. This problem not only takes up the node’slimited storage, resulting in network congestion, but also exacerbated energyconsumption of the sink node, which leads node premature death due to depletion ofenergy. Thus, to resolve this imbalance problem of DTN network resourceconsumption, we conducted the following studies:First, through analyzed the social characteristics of social-based DTN nodes inthe network, including community, centrality, similarity, friendship and selfishness,we have performed in-depth study of the positive and negative social DTN routingprotocols.Second, for the sake of the imbalanced hot spot problem of energy consumptionin the network, the DTN social network is modeled, and the concept of Relativedistance Closeness Degree is proposed. Moreover, the average Relative distanceCloseness Degree is derived by calculating. And also, the simulation results show thatthe average Relative distance Closeness Degree reflects the intensity distribution ofthe nodes in the entire network.Then the concept of edge area is introduced within the nodes’ communicationrange. Meanwhile, the state of the neighbor nodes in the edge area is predicted. Andthen, a method of determining the edge area based on the Relative distance ClosenessDegree is proposed, which means the edge threshold is set to compare with theRelative distance Closeness Degree. And simulation results show that when the threshold value of the edge is0.3, message delivery ratio is high, as well as averageenergy consumption is low.Furthermore, the Relative distance Closeness Degree is introduced to SimBetsocial routing, and taking the residual energy of nodes into account, we have come upwith an improved algorithm based on the Relative distance Closeness Degree, namedSRCD routing algorithm. In order to compare these three routing performance ofSimBet routing and SRCD routing, namely message delivery ratio, the averagetransmission latency and average energy consumption, two Simulation experiments isprovided by changing the simulation time and the number of nodes in the network.Finally, to solve the node congestion and save energy further, the congestioncontrol strategy DB (Drop Biggest) is proposed for SRCD routing and the effects ofDB simulation strategy and DO strategy on routing performance are comparedthrough simulation.In conclusion，Simulation results show that compared with SimBet routingprotocol, although the average transmission latency of SRCD routing increases, itsmessage delivery ratio is much higher. More importantly, in the condition of energysupply network being limited, its average energy consumption is much lower thanSimBet routing.