Time Reversal In The Study Of Electromagnetic Coexistence Problem In Wireless Sensor

Wireless sensor network(WSN) is an intelligent comprehensive information network system which integrates information acquisition, information transmission, and information processing, it involves sensor technology, micro electro mechanical system, embedded computing, network technology, wireless communication technology, distributed signal processing, etc. It is the international attention, multidisciplinary highly cross and knowledge technology highly integrated cutting-edge technology research field.However, with the rapid development of WSN, because of the limitation of the spectrum resources, many wireless sensor network nodes have to deploy densely, plus the phenomenon of much nets coexist, people pay more and more attention to electromagnetic interference phenomenon of WSN. The electromagnetic interference and multipath interference in the application environment is a challenging technical difficult problem in the development of WSN.Time reversal(TR) technique can make full use of the multipath effect to achieve temporal and spatial focusing simultaneously at the target point. Consequently, TR-UWB communication technology can suppress the electromagnetic interference which is encountered by UWB system, and it has the great potential to improve the performance of communication system.This theory firstly presents the review of UWB interference and anti-interference research, and simply presents the development of TR technique.This paper firstly outlines the advantages of wireless sensor network and the existing electromagnetic interference problems and the Research status of this problem at home and abroad, then simply presents the development of TR technique.Secondly, we introduced the basic knowledge of wireless sensor network, and then mainly expounds the electromagnetic compatibility(EMC) problem in wireless sensor this part includes the introduction of system electromagnetic compatibility, the mechanism of electromagnetic interference in WSN, and the traditional anti-interference methods and their shortcomings. We use time reversal technology to solve the low efficiency problem casued by electromagnetic interference in WSN.Next, we mainly introduce the propagation law of TR electromagnetic wave in free space and complex multipath environment, including SISO(Simple-Input Simple-Output) and MISO(Multiple-Input Simple-Output) this two modes, and in each mode, we use different normalized ways, then, we get the statistical law of propagation, finally, we compare the results and get the conclusion.At last, we give the outlook of work, and put forward some suggestions to improve for the follow-up work.