The Spatial Correlation Model And Its Application In Wireless Sensor Networks

Wireless sensor networks (WSN) are characterized by the dense deployment of sensor nodes that continuously observe physical phenomenon. Due to high density in the network topology, sensor observations are highly correlated in the space domain. It can improve network performance drastically to adopt the spatial correlation. So, how to model and exploit the spatial correlation and develop a spatial correlation-base d medium access control (MAC) protocol in WSN are key problems to be solved.The thesis firstly introduces the concept, architecture and character of wireless sensor networks. Then, it introduces the current application of the spatial correlation and some typical MAC protocol in WSN. It also introduces two correlation-based MAC protocols. Last, it introduces the theory of stochastic process in order to provide theoretical and experimental basis for the research in the following chapters.A weigh-based spatial correlation model is proposed the application of WSN in anomaly detection. This model uses the weighs to estimate the information of the event source. Theoretically and experimentally, we show the proposed model is more accurate. It provides a better framework for the development of spatial correlation-based medium access control protocol in WSN.Although the weigh-based spatial correlation model is more accurate, it has some irrationality suppose. This paper proposes a circular spatial correlation model, which is more suitable for the application of WSN in anomaly detection. According to the fact that the observations of nodes, which have the same distance from an event source, are more correlated, we utilize the least square estimation to estimate the information of the event source based on the energy attenuation model. Experimental results show that, for the application of anomaly detection in WSN, our estimation approach is two orders of magnitude accurate than that of the previous model when the number of representative nodes is larger than some small number.We realize an improved spatial correlation-based collaborative medium access control protocol. It selects much less nodes as representation node to send data to the sink, filters out the correlation between sensor observations and reduces the energy consumption effectively. The experiments show that the new MAC has lower medium access delay and energy consumption and so on, embodys the advantages of the spatial correlation-based medium access control protocol better.