Research On Localization And Data Gathering Protocols In Wireless Sensor Networks With Mobile Nodes

Wireless sensor networks are regarded as a new information accessing method and information processing mode, which have linked the logic information world with the objective physical world, changed the way of interaction between human, nature and eventually achieved connectivity among the physical world, the computing world and human society. Node localization is basis of all application for wireless sensor networks, data gathering is a basic application for wireless sensor networks. Nowadays, relative study is mainly aimed at static wireless sensor networks. The static beacon may cause lower localization accuracy, but the mobile beacon can traverse all the area and communicate with all nodes, and then increase localization accuracy. Similarly, the mobile sink can not only transfer high energy consumption area, but also balance node's energy consumption and increase data gathering performance.The major work and innovative achievements can be divided into the following four chapters:(1) An adaptive localization approach for wireless sensor networks based on Gauss-Markov mobility model.In the approach, the perpendicular bisector strategy, the virtual force strategy, and the velocity adjustment strategy are properly combined to enhance localization efficiency. The velocity adjustment strategy causes that the mobile anchor node automatically tunes its velocity. The perpendicular bisector strategy locally adjusts trajectory for the mobile anchor node, which ensures that unknown nodes obtain enough non-collinear anchor coordinates as soon as possible. The virtual force strategy impels that the mobile anchor node rapidly leaves the communication range of location-aware nodes or returns to the surveillance region after the mobile anchor node was out of the boundary. Both theoretical analysis and simulation studies show that this approach can increase localization accuracy, consume less energy, and cover more surveillance region during the same period than virtual beacons-energy ratios localization scheme using the Gauss-Markov mobility model. (2) Four data gathering protocols for wireless sensor networks with mobile sink:EBRP, CRP-FT, IGMM and FCM.EBRP is an data gathering with clustering, random trajectory; CRP-FT is an data gathering with clustering, fixed trajectory; IGMM and FCM is data gathering with non-clustering, random or fixed trajectory.(3) Two event-driven data gathering protocol:EDDGP and ACBP.EDDGP uses the adaptive cluster head evaluating model to elect cluster head. Upon interesting events take place, the member nodes gather them and send to the cluster head. After fusing these data, the cluster head transmit a data collection request packet to the sink. Receiving this packet, the sink moves to the cluster head nearby and gathers data. Both theoretical analysis and simulation studies show that this protocol can prolong to network lifetime efficiently. ACBP is divided into some non-uniform clusters using the adaptive clustering criterion. Upon emergent event take place, the cluster head send a packet to sink. Receiving this packet, the sink moves to the cluster head nearby and gather data.(4) Multi-sinks data gathering protocol is proposed:MSGPMSGP sets some circle cluster head candidate area, fixed member area and public area. Multi-sinks move based on zone division rule and free mobile rule.