| dc.description.abstract | Designing a message forwarding scheme in delay-tolerant networks (DTNs) is a challenging problem due to intermittent connectivity between nodes. The problem of intermittent connectivity makes a node difficult to find an end-to-end path for any source-destination pair in a network. Therefore, the store-carry-and-forward messaging method is used in DTNs.
Movement behavior of humans in real life is not random. A societal relationship exists among nodes. However, dynamic changes of network topology make it difficult to define the general relationship between nodes in a network. This problem motivates the study of this thesis to design a novel message forwarding scheme with dynamic cluster awareness (MDCA), which exploits the nodes’ aggregation phenomenon caused by an implicit relationship among nodes in a network. Because the aggregation phenomenon of nodes will create some clusters in a network, the delivery probability can be improved if messages can be distributed to each cluster.
To achieve this goal, the MDCA design includes seven functional processes: (1) area estimation, (2) cluster decision, (3) quality value update, (4) determining message density, (5) ranking nodes’ metrics, (6) nodes moving in/out of a cluster, and (7) message transmission. Thus, the main idea of MDCA is as follows. First, the node calculates the expected density of nodes in process 1. Secondly, the node determines whether it is in a cluster or not in process 2. Lastly, the node chooses the appropriate relay nodes to carry messages in a cluster through processes 5 and 6. In addition, the MDCA controls the quantity of message copies by determining the message density, i.e., process 4. Furthermore, this study conducts many simulations with various mobility models, including random waypoint (RWP), time-variant community mobility model (TVCM) as well as real trace Infocm06. Performance results show that the MDCA has better delivery probability in the mobility models related to human behavior. | en_US |