Research On Routing Strategy Based On Node Sociality In Disaster Scenarios

Delay Tolerant Networks(DTNs)are used in challenging environments where there is no stable link between the source node and the destination node.DTNs use "storecarry-forward" communication model to forward messages since there isn't a persistent end-to-end path.In an environment where communication links are frequently interrupted after a disaster,the traditional wireless communication networks could not work normally due to severe damage to the infrastructure,especially in remote isolated areas.Compared with traditional wireless communication networks,DTNs can achieve communication under the conditions of intermittent connection,changeable network topology and limited network resources.Although the "storage-carry-forward" transmission mechanism solves the problem of data transmission in a intermittent networks,there are also problems such as low data transmission efficiency and large transmission delay.How to design efficient routing algorithms for different application scenarios is the primary issue of delaytolerant networks research.Based on the post-disaster scenario and the social analysis of the nodes,this thesis focuses on the delay-tolerant network routing strategy suitable for post-disaster scenarios.The specific research content is as follows:1.A routing strategy for selective forwarding of messages based on regional properties.In the case of geographical partition due to disaster,a fixed throwbox is added as the regional central node at each regional gathering point.The regional center node can collect and store the message packets in the region and regularly interact with the UVA ferry node to achieve the large-scale data transmission across the region.Considering the crowd's activity rules and movement characteristics after the disaster.The ferry node and the regional center node can divide the message packets according to the destination address,so that the message packets are directly and accurately delivered to the destination area,and thereby reducing the network overhead rate and improve the data delivery rate.2.A routing strategy based on node sociality.Aiming at the problems of low data delivery rate,large network overhead,and high transmission delay in the existing DTN,a routing strategy based on node sociality is proposed by using improved Spray and Wait routing algorithm.After the disaster,information such as node movement,social attributes,and geographic location has a great influence on the performance of the network.Therefore,the traditional Spray and Wait algorithm need to be improved.In the spraying stage,the node's utility value is defined based on the node's intimacy and similarity,and a more reasonable relay is selected according to the node's utility value.The distribution of the number of nodes and message copies ensures that the number of message copies owned by the node matches the message forwarding capabilities of the node.In the waiting phase,a routing strategy based on the geographic location of the node is proposed,and the node transmission utility value is defined by the speed,angle and distance,and the node with smaller transmission utility value,the message copy is forwarded twice to improve the network performance.Finally,the ONE simulation platform is used to implement the algorithm proposed in this paper.Experiments show that the proposed method is more competitive than the comparison algorithms and the overall performance is better.