The Research On Medium Access Control Protocol Based On Spatial Correlation In Wireless Sensor Networks

In wireless sensor networks(WSN), sensor nodes are usually deployed densely so that the data transmitted by the adjacent nodes show a certain degree of relevance. Mining spatial correlation that exists in WSN and applying it to designing a proper medium access control (MAC) protocol are very significant for improving the performance of the WSN. This paper delves into spatial correlation-based MAC protocol. Its main tasks are the following aspects:Firstly, this paper gives a general overview of the current research about the WSN, such as its architecture, features and typical applications. And then it will continue to give a general overview of the MAC protocol, and summarize the main research contents and the current research focus. What's more, this thesis focuses on the analysis and comparison of two kinds of spatial correlation-based MAC protocol.Secondly, we propose a new node importance and spatial correlation-based MAC protocol(NISC-MAC), which defines the smaller nodes interrelated, i.e., the nodes with great data difference, as the important nodes, and attributes it high priority. Those high priority nodes can send data with highly probability and backoff time shortly so that it is given highly priority in the competition to channel. And they can choose out the important nodes as the representative nodes, make sure those vital data send successfully to the Sink node. It is not only removal of spatial correlation of data, but also to ensure the overall effectiveness of data. The simulation experiment indicates the NISC-MAC ensure the overall effectiveness of data under low energy consumption and transmission delay.Thirdly, we propose a low-latency MAC for spatial correlation and data gathering(SD-MAC). SD-MAC chooses the representative nodes according to the spatial correlation. When these representative nodes send data, other nodes are dormant. All the nodes form into a data gathering tree and then send the data to the Sink node through the staggered scheduling mechanism of the MAC. The selection of the representative nodes and the staggered scheduling mechanism help to reduce the amount of sent data and the collision of them, thus significantly reducing the data transmission delay and network energy consumption. Simulation tests show that the SD-MAC protocol can reduce the latency of the media access more than that of other MAC protocols, it not only can satisfy real time applications, but also has good throughput, low packet loss rate and low average energy consumption.