Study Of Key Issues In Wireless Sensor Networks Based On Mobile Sink

With the development of MEMS, embedded technology, modern network, wireless communications and distributed information processing technology, wireless sensor networks synthesize all the new technologies. The sensor nodes can implement real time monitoring, sensing and collecting the information from the monitored objects. The information will be transmitted inside the network in multi-hop ways until they arrive at the user. Among the different kinds of WSNs, MSWSNs attract the more focuses because of their special characteristics. While mobile sinks wireless sensor networks can balance the energy comsunmption of the nodes and the sinks will be more easily to get all the information. Localization is one of the challenges in the development of the wireless sensor networks among all the research which have been done in recent years. It is a problem to guarantee the precise localization on the premise of the low cost comsumption. Furtheremore, based on that design for the applications, how to design an efficient data collection strategy is a great challenge for such wireless networks.In this thesis, we study the design and evaluation of efficient and localization schemes for mobile sink wireless sensor networks. The main contributions of this dissertation are as follows:Range-boundary aware mobility localization scheme in wireless sensor networks aiming at the localization of the sensor nodes(RAML). The main objective of the algorithm is to predict the sensor nodes with the help of the mobile sink(s). A simple and effective localization scheme was proposed on the premise of the given track of the mobile sink. It is a cost-effective scheme which designed for energy-limited wireless sensor networks. This range-boundary localization scheme was based on the transmission range; we proved the scheme can achieve the acceptable localization errors through simulation results. Compared with other localization schemes, it is appropriate for the requirement of the wireless sensor networks. Dynamic prediction algorithm for mobile sink based on initial locations. The design objective of this prediction algorithm is to predict the location of the mobile sink dynamically so as to achieve the efficient transmissions. In detail design, after receiving 3 initial location information of the mobile sink, the sensor nodes will predict the next locations in certain period. Through simulation results, the dynamic prediction algorithm effectively avoided the flooding inside the sensor network and saved the transmission cost.Efficient data collection in wireless sensor networks by applying network coding (EDC-ANC). It is designed for the insentive data transmissions with ubiquitous mobile sinks. This scheme proposes an efficient data collection in such a wireless networks. To the unstable wireless links in wireless sensor networks, network coding can be applied in efficient data collections. Parts of the sensor nodes will be responsible for data transmissions in ubiquitous collections, through network coding the sensor nodes can combine different incoming packets into linear independent packets. It can improve the throughput in the whole network and through decoding algorithm the original packets can be achieved under the circumstance of enough data collections according to the collected data packets which the mobile sink receives. Network coding can obviously decrease the tranmsmisson numbers and increase the received packets rates in the event of unstable wirless links.Efficient data delivery scheme for mobile wireless sensor networks with ubiquitous mobile data collectors (WFS). With the comparison of the neighbor nodes and itself, the node selects the forwarding node with the maximum possibility to meet with the mobile sinks. This scheme is based on the experience construction and maintainance; the sensor node will save the interaction information with the multiple mobile sinks. Usually this kind of scheme is used in DTN(Delay Tolerant Networks), but our improved scheme can improve the performance of transmission delay in mobile wireless sensor networks.