Delivery Ability-Aware Message Transmission Mechanism In Opportunity Network

The rapid development and popularization of intelligent terminals which promote the development of mobile communication technology makes many networks,which possess new structures,had been proposed.In these networks,nodes communicate with each other using ?storage-carrying-forwarding? method owing to the links of nodes are intermittently connected,and the delay of message transmission is relatively high and transmission protocol based on end-to-end path in traditional networks can not be directly applied to in this networks.The opportunity network,which is widely used of in such networks,has attracted multitudinous attentions of researchers,and researchers found that the movement of nodes in opportunity network which formed by the human beings carried intelligent terminals is closely related to people's daily social activities and shows some sociological characteristics.It can effectively improve the network performance of message transmission mechanism and provides a new research direction in opportunity network research if using the sociological characteristics of node to design message transmission mechanism.In this thesis,a message transmission mechanism was carried out based on delivery ability which is analyzed through the study of relationship beteen node mobility and node social relations in social network.The specific research contents include the following two aspects:Considering the diversification of node relation influences message transmission performance and the relationship between node relation and node motion,this thesis proposes a node relationship magnanimity aesthesis routing.The encounter information of node motion is uesd to measure node relationship magnanimity and forwarding capability which are used to evaluate the delivery probability of message combining node relationship magnanimity.Finally,selecting the node which will carry message is based on the utility value of delivery probability.The simulation results show that the proposed rouring mechanism can significantly reduce the transmission delay,network overhead and message delivery ratio.Considering the similarity of node mobility can be used to judge whether the node is suitable for messages transmission to influence messages delivery ratio,this thesis proposes a cache management strategy using motion similarity.In this cache management strategy,the probability of message transmission is estamated in the cache by analyzing the diffusion degree of message replicas and the moving characteristics of nodes in the network,and combining node motion similarity and message motion similarity to estimate utility of message storage and forwarding.Then the set of messages that are appropriate for node forwarding and the order in which the message needs to be discarded when the node buffer overflows are selected based on utility value.Finally,the result using simulation platform to realize the strategy shows that the proposed strategy has higher delivery rate,lower cost and transmission delay compared with other cache management strategies.