DCAR: DTN Congestion Avoidance Routing Algorithm Based on Tokens in an Urban Environment

When a delay/disruption tolerant network (dtn) is applied in an urban scenario,the network is mainly composed of mobile devices carried by pedestrians,cars,and other vehicles,and the node's movement trajectory is closely related to its social relationships and regular life; thus,most existing dtn routing algorithms cannot show efficient network performance in urban scenarios. in this paper,we propose a routing algorithm,called dcra,which divides the urban map into grids; fixed sink stations are established in specific grids such that the communication range of each fixed sink station can cover a specific number of grids; these grids are defined as a cluster and allocated a number of tokens in each cluster; the tokens in the cluster are controlled by the fixed sink station. a node will transmit messages to a relay node that has a larger remaining buffer size and encounters fixed sink stations or the destination node more frequently after it obtains a message transmit token. simulation experiments are carried out to verify the performance of the dcar under an urban scenario,and results show that the dcar algorithm is superior to existing routing algorithms in terms of delivery ratio,average delay,and network overhead. © 2017 hezhe wang et al.