Message Delivery In Delay Tolerant Networks Research Articles

Fairness in message delivery in delay tolerant networks

Rare existence of the end-to-end path and intermittent connectivity among the nodes are the key characteristics of delay tolerant networks (DTNs). Such networks are potentially applicable in challenged environment like post-disaster situation, where traditional communication infrastructure is partially or fully absent. Significant research efforts are made to develop data forwarding schemes which are efficient in terms of delivery ratio in DTNs. However, fairness in message delivery is a less investigated topic in DTN routing. In most of the traditional data forwarding schemes, delivery of a message varies depending on its destination. Each destination in the network may not receive its intended messages with the same success rate. But in real-life applications, e.g. post-disaster environment, fair delivery of the messages to each destination is imperative for conducting relief operations properly. In this paper, we address the issue of fairness in message delivery in DTNs. In order to achieve fairness in message delivery, we analyze the influence of important parameters on successful message delivery. Based on this analysis, we design a metric for relay selection and subsequently propose a relay selection scheme for fair message delivery in DTNs. Performance of our proposed scheme is evaluated in ONE simulator considering realistic node-mobility map based on a recent post-disaster situation. Comparative results show that the proposed scheme achieves more impressive fairness in message delivery than the other competing schemes while achieving acceptable delivery ratio and low overhead ratio in the network.

Using Stationary Relay Nodes (Thrown Boxes) to Maximize Message Forwarding Performance in Delay-Tolerant Networks

This paper addresses the efficiency on message forwarding over heterogeneous nodes in DTNs. Among the approaches for routing protocols in DTNs, the strategy of deploying the stationary relay nodes called ＂thrown boxes＂ is considered for increasing network performance efficiently. Till now, few studies have provided routing solutions for thrown-box-based network paradigms in the DTN research field. The technical content of this paper includes three parts. Firstly, this study considers the deployment of thrown boxes that can assist in message delivery in delay-tolerant networks. A utility-based algorithm is applied to make the message forwarding decision between two nodes whenever they are in contact. Secondly, we study where to appropriately deploy thrown boxes under various scenarios. Finally, this study runs simulations to evaluate the proposed scheme in terms of message delivery probability. Performance results show that the proposed algorithm achieves high performances and thrown boxes play an important role in message forwarding performance.

An energy-aware deadline-constrained message delivery in delay-tolerant networks

In order to understand the message dissemination performance in delay-tolerant networks, much analysis work has been proposed in literature. However, existing work shares a common simplification that the pairwise inter-meeting time between any two mobile nodes is exponentially distributed. Not mention the fact that such assumption is only an approximation, it cannot be applied by network planners to directly control the mobile nodes for any network optimization, e.g., energy efficiency. It is quite significant to study the relationship between the network performance with the parameters that can be adjusted directly to tackle the limitations of current exponential distribution assumption based analysis. Therefore, in this paper, we are motivated to jointly consider the transmission range and messages residence time to stochastically analyze deadline-constrained message delivery ratio utilizing a controlled epidemic routing. The message propagation is considered as an age-structure process and described by a susceptible---infectious---recovered model, which is then analyzed using delay differential equations. Since both the transmission range and the message residence time are related to the mobile nodes' energy consumption, we further apply our analysis framework to investigate the tradeoff between the energy consumption and the achievable message delivery ratio. The correctness and accuracy of our analysis are validated by extensive simulations.