Routing Strategies and Cooperation Incentive Mechanisms for Delay Tolerant Networks

Most of conventional routing protocols based on always-existing end-to-end paths, are not applicable in delay tolerant networks (DTNs), in which nodes are intermittently connected. DTNs, as an emergent communication paradigm, enable transfer of messages among intermittently connected nodes. Applications of DTNs include social networks, vehicular networks, pocket switched networks and habitat monitoring sensor networks, which challenge the research of DTNs from aspects of routing, cooperation incentive, security and privacy, etc.;Firstly, this dissertation proposes to use the contact expectation for DTN routing. EER is first proposed including multiple replicas distribution and single replica forwarding. CR is further proposed, which takes advantages of high contact frequency property of community. The simulations demonstrate the effectiveness of the proposed EER and CR protocols.;Secondly, this dissertation proposes a cooperative routing protocol using group feature for DTNs under resource constraints, including cooperative message transfer scheme and buffer management strategy. In cooperative message transfer scheme, the message transfer priorities are designed to maximize the delivery probability. In the buffer management strategy, the cooperative message caching scheme is proposed and the dropping order of the messages is designed to minimize the reduced delivery probability. The simulations are conducted to demonstrate the effectiveness of the proposed group aware routing protocol.;Thirdly, this dissertation considers the noncooperative DTNs, in which nodes may be selfish and reluctant to cooperate with each other. Two credit-based rewarding schemes, called EPSR and EPCR respectively, are proposed to ensure nodes truthfully forward messages. The proposed rewarding schemes are proved to be incentive compatible and the payment for each delivered message is upper bounded. Furthermore, the proposed schemes can prevent selfish nodes from having malicious behaviors. The real-trace based simulations are conducted to illustrate their effectiveness.;Finally, this dissertation proposes to protect the end-to-end location privacy in the delay tolerant event collection systems. Previous research only focuses on location privacy of source or sink independently. In this dissertation, four schemes called FRW, BT, DBT and ZBT respectively are proposed to protect the location privacy of source and sink simultaneously. Simulation results illustrate the effectiveness of the proposed schemes.