Research On The Application Of Signal Detection Theory To The Target Detection In Wireless Sensor Networks

Based on a series of application needs of the environmental monitoring and targets tracking, WSN( Wireless sensor networks) is proposed. As an emerging wireless self-organizing networks technology, improvement of the targets detection efficiency of the WSN is a very important aspect of the research. Therefore, the problem of WSN signal detection is one of the key issues of its application and research.In this paper, based on the classic method of signal detection theory, combining WSN signal propagation model and the spatial correlation theory, analyzing the ED(Energy Detector) and CD(Covariance Detector) detection performance. In order to analyze and compare the ED and CD detection performance, the paper defines the coverage area and uses the indicator of coverage area, theoretically analyzing the detection performance of the two detectors. Aiming at the problem of WSN’s target detection, from three aspects the paper researched the single-point independent detection, two-point joint detection and three-point joint detection.Researching on single-point independent detection and two-point joint detection,the paper mainly used the indicator of the definition of the coverage area, theoretically analyzed and compared the coverage area obtained from the two testing programs. For ED it can be concluded that, the use of two-point joint detection can obtain better testing results than the single point independent detection. In the study of ED participated in two-points joint detection, mainly focus on studying the performance of the two-points joint detection using ED which participate in two ways of AND &OR.The analysis of the two-point joint detection performance in which ED and CD participated, it can be concluded that, when the distance between nodes is short, using the CD detection you can get better results than using ED detection. However, when the distance between nodes is increased, the better result can obtained using the ED detection in the way of OR. Analysis about coverage areas obtained from the two-points joint detection in which the ED participated, it can be concluded that when the distance between the nodes is shorter than a certain value, two-points joint detection using the ED in the way of AND can obtain a better performance than using the ED in the way of OR; on the contrary, when the distance between nodes exceeds the specified value,two-points joint detection using the ED in the way of OR can obtain a betterperformance than using the ED in the way of AND. About using the ED participating in the two-points joint detection, this article also gives the solving algorithm about the performance point between the way of AND & the way of OR.The paper also theoretically investigated problems about the three-point joint detection, firstly based on the two basic detectors of ED and CD, designing a detector which is fit for the three-point joint detection. In order to compare the detection performance of the three-point joint detection to the detection performance of single-point detection and two-point joint detection, designing an algorithm which can draw detector detection probability distribution of the detection area. Through this method, analyzing performances of the single-point independent detector detection,two-point joint detection and three-point joint detection, it can be concluded that the use of three-point joint detection will make the detector performance degradation. Therefore,the use of two-point joint detection can obtain the best detection result.