Research On Routing Techniques In Delay Tolerant Wireless Sensor Networks

The Delay Tolerant Wireless Sensor Network(DTWSN) can work in the place where traditional network cannot cover. Because of the extreme deployment environment, the data transmission, which is the most important function of network, will be challenging. Unlike traditional network, the Delay Tolerant Wireless Sensor Network needs to consider many extreme network scenarios. So the DTWSN routing protocols will be designed according to different application scenarios.Based on the survey of the DTWSN in this thesis, we analyzed network architecture, character, classification and application prospect of the DTWSN detailedly. And then we proposed efficient routing protocol according to different application scenarios.(1) Under multi-copy routing transmission mode, we proposed a comprehensive dynamic dissemination metric Expect Delay(ED), which is a function of remaining hops and remaining time to live. We proposed a backward recursive algorithm to calculate the dissemination metric. Based on this, we proposed the Optimal Delay Copy Dissemination protocol(ODCD). In order to optimize ED of each message which satisfies the certain constant on the number of copies, ODCD modeles copy dissemination question as optimal stopping rule, and minimizes ED of each copy in every discrete time slop.The simulation on real contact data set from Andrews University has been given.(2) Under mobile infrastructure based network scenario, we proposed the Optimizing Sub-Tree Path Length(OSTPL) data collection protocol. The OSTPL makes a distributed optimization on the length of path between child nodes and the aggregation nodes, and decreases the energy consumption of wholly network efficiently. We demonstrated the validity of OSTPL by the mathematical model which utilized Lindburg-Levy central limit theorem. The simulation results show that OSTPL can lower the network energy consumption and extends the network lifetime efficiently, when keep the delay in same level of other hierarchical data collection protocols.In conclusion, meticulous analysis and research has been made in the Delay Tolerant Wireless Sensor Network on multiple network scenarios. And then we proposed two kinds of routing protocol aimed at different application scenarios. The research results will be meaningful in Delay Tolerant Wireless Sensor Network routing protocol design and application.