tailieunhanh - Báo cáo hóa học: " Research Article Positioning Based on Factor Graphs Christian Mensing and Simon Plass"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Positioning Based on Factor Graphs Christian Mensing and Simon Plass | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2007 Article ID 41348 11 pages doi 2007 41348 Research Article Positioning Based on Factor Graphs Christian Mensing and Simon Plass German Aerospace Center DLR Institute of Communications and Navigation Oberpfaffenhofen 82234 Wessling Germany Received 16 November 2006 Revised 15 March 2007 Accepted 16 April 2007 Recommended by H. Vincent Poor This paper covers location determination in wireless cellular networks based on time difference of arrival TDoA measurements in a factor graphs framework. The resulting nonlinear estimation problem of the localization process for the mobile station cannot be solved analytically. The well-known iterative Gauss-Newton method as standard solution fails to converge for certain geometric constellations and bad initial values and thus it is not suitable for a general solution in cellular networks. Therefore we propose a TDoA positioning algorithm based on factor graphs. Simulation results in terms of root-mean-square errors and cumulative density functions show that this approach achieves very accurate positioning estimates by moderate computational complexity. Copyright 2007 C. Mensing and S. Plass. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. 1. INTRODUCTION Positioning in wireless networks became very important in recent years. Services and applications based on accurate knowledge of the location of the mobile station MS will play a fundamental role in future wireless systems 1-3 . In addition to vehicle navigation fraud detection resource management automated billing and further promising applications it is stated by the United States Federal Communications Commission FCC that all wireless service providers have to deliver the location of all enhanced 911 E911 callers with