Study Of Routing Protocols For Delay Tolerant Network Based On Historical Intervals Of Contacts

In Delay Tolerant Networks (DTNs), since network connects intermittently,the network topology changes dynamically and the network delay latency is high,a continuous end-to-end path between a destination and a source may not ever exist. Therefore, the widely used routing protocols such as TCP/IP, can't be used for DTNs.The research of routing protocols has become the core issue of Delay Tolerant Networks, and has become an open and independent field of research.This paper is based on analyzing existing routings and social nature, and designs two different protocols suitable for each scenario.Human social attributes determine that human communicate with familiar friends, relatives and colleagues in specific environment. Thus a specific community is formed. Members of the same community are in frequent contact.As a consequence, the encounter time interval between them is relatively short and the relationship between members of the society is a transitive. According to the characteristics of human society and Delay Tolerant Network, a routing protocol based on historical encounter time interval is proposed in this paper. In view of the disadvantages of the most Delay Tolerant Network routing algorithm in finding end to end links, we proposed a routing protocol based on the historical time intervals of contacts(HIoC). In this algorithm, we take the historical encounter time interval as the utility value to forward the messages so as to improve the resource depletion caused by flooding.The energy and the buffer are limited resources in wireless sensor networks.Due to the lack of energy, the node will lead to a short division of the network. So it is very important to select the relay node reasonably and improve the utilization rate of the battery and the buffer. In this paper, we present the resource-efficient routing protocol based on historical encounter time interval (RRPHETI).RRPHETI aims at considering the energy and buffer capability when selecting relay nodes and limiting replicas. RRPHETI creates a model to capture the resource consumption behaviors in DTN, and utilizes the maximum likelihood method to estimate the parameters of delivery probability. RRPHETI exploits historical encounter time interval to measure social relations between nodes. The more intimate the nodes are, the smaller the encounter time interval becomes. At last, RRPHETI formulates the utility value of a node as a criterion for packet forwarding so as to make the messages flow in the direction of the destination node.Firstly, the background of Delay Tolerant Networks, existing research and research target are given in this paper. Secondly, the advantages and disadvantages of various routes are summarized. Then, routing protocols for Delay Tolerant Network based on historical intervals of contacts are proposed. In the end, the protocols are deployed in a better selection of routing simulation platform---ONE(Opportunistic Network Environment simulator). HIoC, RRPHETI, Epidemic and PRoPHET routings are compared in efficiency in this paper. Experimental data shows that, in the scenario with social attributes, HIoC routing ensures high delivery ratio, small overhead and small delay ratio. So HIoC is suitable for DTN and is an effective routing protocol. In the resource constrained network scenario,RRPHETI achieves higher delivery ratio, better overhead ratio and average delay with minimal energy consumption compared to other protocols.This paper proposes routing protocols for delay tolerant network based on historical time intervals of contacts successfully, and proves the advantages of both routings. The design of the algorithm is innovative and practical. The routing algorithm has a certain reference value for the study of history-based and resource-based Delay Tolerant Network routing algorithm.