Research On Bulk-data Dissemination Algorithm In Low-duty-cycle Wireless Sensor Networks

Wireless sensor network is a multi-hop and self-organizing network,composed of a large number of sensor nodes which are randomly deployed in the monitoring area to coordinate and transmit the collected data.With a large number of nodes and a complex environment in which staff are often unable to manually collect and reconfigure nodes,bulk data dissemination protocol is used to resolve network update problems.Nowadays researches on bulk data distribution protocols are focused on the non-duty cycle mode,which improves the efficiencies of node transmission and energy.For general Wireless Sensor Networks,the related applications usually work in the low-duty-cycle MAC protocol to reduce the energy consumption.But the low-duty-cycle mode makes it difficult for nodes to know the neighbor information accurately,which results in the failure of dissemination decision,and increases the dormant delay in the dissemination completion time and the complexity of the algorithm design.Since antennas don't always remain in the open position,nodes are often unable to give full play to the broadcast advantage of the Nonduty-cycle work mode.This thesis introduces a study of bulk data dissemination algorithm in low-duty-cycle wireless sensor networks.Main contents:In order to obtain accurate and reliable neighbor information,this thesis first designs and realizes the algorithm of neighbor discovery and link quality evaluation(NDLEP)for lowduty-cycle wireless sensor networks.Based on the predictability of PW-MAC protocol,the NDLEP algorithm uses the rendezvous mechanism and the cooperative neighbor discovery mechanism to accomplish the neighbor discovery,and realizes the link quality evaluation with the aid of the receiving signal strength indicator and the broadcast beacon frame.NDLEP accelerate the discovery process of neighbor nodes,compared with the 4-Bits protocol in the model of n on-duty-cycle,the accuracy of the link quality evaluation of NDLEP is decreased,but the node's low energy consumption is ensured.Secondly,this thesis designs the dissemination protocol BDPS-BASE based on PW-MAC protocol.The BDPS-BASE protocol uses the underlying overhearing policy and the way of transmission.Compared with Deluge,the energy consumption of BDPS-BASE is reduced,but the dissemination time is longer.In order to shorten the dissemination completion time,this thesis puts forward the BDPS protocol based on the BDPS-BASE,the BDPS protocol takes the node's level,link quality,dormant delay and data transmission time into account on the dissemination completion time and establishes the minimum expected completion time dissemination tree(MEDT).Based on the MEDT,the BDPS protocol determines the priority of the neighbor nodes,and uses the data stream switching and merging methods to shorten the dissemination completion time of the key nodes based on the priority.BDPS design the sender strategy,active overhearing and window mechanism,reduce the redundant data transmission,improve the single transmission efficiency and make up for the broadcast disadvantage under the duty ratio mode.Finally,the BDPS protocol is designed and implemented on the TOSSIM,and the validity of the protocol is verified by TOSSIM simulation experiment,and the comparison is made between the Deluge and BDPS-BASE protocols in dissemination completion time,energy efficiency and scalability.The experimental results show that energy consumptions of BDPSBASE and BDPS is close and both of them are much lower than that of Deluge.In addition,the dissemination completion time of BDPS is less than that of Deluge.