Research On TOA Estimation Technology In Multicarrier Location System

With the development of next-generation location-aware wireless networks and theemergence of more location-based services, positioning tracking technology has becomemore and more important. As one of the ranging positioning methods, location fidingbased on TOA estimation is the most popular method for highly accurate positioningsystems.Meanwhile. A basic problem TOA positioning technology faces is how toaccurately estimate the propagation delay of the radio signal arriving from the directline-of-sight propagation path. In multipath environment, such as indoor or densebuilding areas, TOA positioning precision can’t meet the demand of location servicebecause of the serious multipath effect and the limited accuracy of TOA estimationalgorithm. On the other hand, OFDM technology, because of its stronger resistance tomultipath effects and frequency utilization efficiency high characteristic, is widelyapplied in wireless communication system. Therefore, TOA estimation algorithm inOFDM system research has become the research emphasis in this paper.In this paper, research and analysis of multi-carrier positioning system TOAestimation techniques is carried out, and research work are as follows:1) First, three time-based synchronization TOA estimation algorithms areintroduced and their simulation and performance comparison are implementedrespectively. Then the basic principles of IFFT-TOA algorithm the MUSICsuper-resolution algorithm are illustrated, and their performances are estimated.2) Through to impoving the traditional MUSIC super-resolution algorithm, twoenhanced MUSIC algorithms are proposed: First, channel estimation is improved andcorrelation matrix characteristics analysis of the time-domain sinusoidal signal isapplied to MUSIC algorithm.All of that will generate CB-MUSIC algorithm. What’smore, ICA algorithm, which is often utilized in broadband sound source separation,radar signal processing and so on, is combined with MUSIC. After that, ICA-MUSICwill emerge through separating every signal from all paths. Two improved algorithmsdenoise in different ways, but it is realized in the low SNR case that direct diameterTOA estimation accuracy is improved. 3) Positioning system simulation model is constructed. At the first, estimatonperformance of both CB-MUSIC algorithm and the ICA-MUSIC algorithm is evaluatedand simulation results show that two kinds of enhanced MUSIC algorithms still havehigh resolution and estimation accuracy, compared with the traditional MUSICalgorithm in low SNR. In addition, ICA-MUSIC algorithm is a litttle more accurate thanCB-MUSIC algorithm. Then influences on the accuracy and stability of three kinds ofMUSIC algorithm from the different search window parameters are deeply reffered to.Finally, the multiple sets of TOA estimation results through multilateral localizationalgorithm, are made use of estimating the position of the mobile node, And the resultsshow that the ICA-MUSIC algorithm achives optimal performance, and traditionalMUSIC algorithm is the worst.