Maximizing timely content advertising in DTNs

Many applications, such as product promotion advertisement and traffic congestion notification, benefit from the opportunistic content exchange in Delay Tolerant Networks (DTNs). An important requirement of such applications is timely delivery. However, the intermittent connectivity of DTNs may significantly delay content exchange and cannot guarantee timely delivery. The state-of-the-arts capture the mobility patterns or social properties of mobile devices. However, there is little optimization in terms of the delivered content. Without such optimization, the content demanded by a large number of subscribers could follow the same forwarding path as the content by only one subscriber. To address the challenge, in this paper, we separate content routing from content forwarding. For content routing, we leverage content properties to derive an optimal routing hop count for each content in order to maximize the number of nodes which receive demanded content. Next, for timely forwarding, we develop node utilities to capture interests and mobility patterns of mobile devices for the selection of content carriers. The distributed greedy relay scheme, Ameba, leverages the optimal routing hop count and developed utilities to timely relay content to the needed nodes as fast as possible. Illustrative results show that Ameba is able to achieve comparable delivery ratio as the Epidemic but with much lower overhead.