Data Aggregation And Delay Controlling In Wireless Sensor Networks

Wireless sensor networks is a new developing technology started in the 1990s last century. Along with technological development, its all kinds of applications are spreaded widely. Having energy constraints, Sensor nodes need use data aggregation technology to reduce the amount of data transmissed, It can reduce energy consumption in communication and increase wireless sensor networks's service life.This thesis discusses the effection and the classification about data aggregation, the relationship of data aggregation and sensor network protocol layers. Focused on routing approachs combined with various data aggregation in the network layer and some kinds data-level data aggregation methods.On routing approachs combined with data aggregation methods in the network layer, thesis discusses a variety of data aggregation methods based on the routing. It analysises a new aggregation method: center aggregation algorithm's defects, and puts forword a improved algorithm. On the data-level data aggregation methods, thesis discusses the D-S evidence reasoning theory and adaptive weighted data aggregation algorithms. In adaptive weighted data aggregation algorithms, it need expert's assessment or do a massive amount of time-domain computing, bringing large inconvenience to wireless sensor networks's applications. Therefore, in this thesis, I put forward a new kind data aggregation method: unit data aggregation method. It use sensor networks node's current values to carry on cluster analysis and classify node's current values, using every cluster of current value to do data aggregation with D-S evidence reasoning theory. and then it use current aggregation results to carry on discriminant analysis, applying Mahalanobis distance to analysis abnomoral value of current aggregation result's vector as weighted estimate algorithm's weight, The final result can be found effective.Finally thesis preliminary discusses the relationship of inquiry accuracy and inquiry delay, and the impact between inquiry accuracy and inquiry delay. under ensuring the inquiry accuracy, thesis puts forword a kind of delay control method.