An Information Search Algorithm Based on Query Delegation and Feedback Delegation in Delay-Tolerant Networks

In this paper, we propose a new three-hop information search algorithm in delay-tolerant networks. In this algorithm, information search is divided into two phases, query and feedback. In the query phase, the query's source user entrusts neighbors as query nodes to reach the purpose community and obtain the relevant information. In the feedback phase, every query node entrusts his neighbors as feedback nodes to give the information feedback to the query's source user. We apply a semi-Markov model to predict the user's future location. In the former phase, we select the nodes with higher query probabilities as the query delegations. Then the concept of first arrival time is defined here. In the latter phase, if the feedback probability of a neighbor node is higher than that of the query node, we will select it as a feedback node. We define this algorithm as query and feedback delegation(QFD). Through simulation, the results show that QFD not only improves the information query ratio but also reduces average delay for information query compared with the existing query schemes.