An Improved spray-and-wait Routing Algorithm Based on Social Relationship between Nodes in DTN

In delay tolerant networks(DTN), non-social attributes and social attributes relating to nodes have a different effect in designing router algorithms, we can combine these two different attributes to design algorithms. In our paper, we put forward an improved spray-and-wait routing algorithm (NSSAWRouter) based on social relationship between nodes in DTN, which mainly selects relay nodes by adopting two different transmission values and assigns message copies between two nodes dynamically in the spray stage. Specifically, we will first build social circle nodes for each node and record the dynamic social relationship between a node and its social circle nodes. Followed by it, we introduce a concept called social transmission value, which is used to estimate the likelihood of a node comprehensively transmitting a message to the special node that message should be delivered to when the social circle nodes of the node contain the special node. Similarly, we use non-social transmission value to select relay nodes when the two encountered nodes' social circle nodes both do not contain the special node, which consists of node activity and delivery predictability. Finally, we use the proportion of two nodes' non-social transmission value or social transmission value to assign message copies, making nodes that have greater ability to send messages to the special node carry more message copies. The results of the simulation experiment illustrate that the algorithm proposed can increase the delivery rate and keep a relatively lower overload in comparison with DirectDelivery, Epidemic, Prophet, Spray and Wait, MASSRouter.