Title :
Accurate approximation algorithm for TOA-based maximum likelihood mobile location using semidefinite programming
Author :
Cheung, K.W. ; Ma, W.-K. ; So, H.C.
Author_Institution :
Dept. of Comput. Eng. & Inf. Technol., City Univ. of Hong Kong, China
Abstract :
The techniques of using wireless cellular networks to locate mobile stations have recently received considerable interest. The paper addresses the problem of maximum likelihood (ML) location estimation using (uplink) time-of-arrival (TOA) measurements. Under the standard assumption of Gaussian TOA measurement errors, ML location estimation is a nonconvex optimization problem in which the presence of local minima makes the search of the globally optimal solution hard. To circumvent this difficulty, we propose to approximate the ML problem by relaxing it to a convex optimization problem, namely semidefinite programming. Simulation results indicate that this semidefinite relaxation location estimator provides mean square position error performance close to the Cramer-Rao lower bound for a wide range of TOA measurement error levels.
Keywords :
cellular radio; convex programming; maximum likelihood estimation; mean square error methods; measurement errors; relaxation theory; Cramer-Rao lower bound; Gaussian errors; TOA measurements; accurate approximation algorithm; convex optimization problem; maximum likelihood estimation; maximum likelihood location estimation; mean square error; measurement error; mobile station location; nonconvex optimization problem; semidefinite programming; time-of-arrival measurements; wireless cellular networks; Approximation algorithms; Electronic mail; Estimation error; Global Positioning System; Information technology; Land mobile radio cellular systems; Least squares approximation; Maximum likelihood estimation; Measurement errors; Measurement standards;
Conference_Titel :
Acoustics, Speech, and Signal Processing, 2004. Proceedings. (ICASSP '04). IEEE International Conference on
Print_ISBN :
0-7803-8484-9
DOI :
10.1109/ICASSP.2004.1326215