Browsing by Subject "Wireless positioning"

Now showing 1 - 3 of 3

Open Access
Enhancements to threshold based range estimation for ultra-wideband systems
(IEEE, 2014-09) Soğancı, Hamza; Gezici, Sinan; Güldoğan, M. B.
Ultra-wideband (UWB) signals have very high time resolution, which makes them a very good candidate for range estimation based wireless positioning. Although the accuracy is the major concern for range estimation, it is also important to have low-complexity algorithms that can be employed in real time. In this study, two low-complexity range estimation algorithms are proposed for UWB signals, which achieve improved performance compared to the state-of-the-art low-complexity ranging algorithms. The proposed algorithms are inspired from two well-known algorithms; 'serial backward search' (SBS) and 'jump back and search forward' (JBSF). Performances of the proposed algorithms are compared with those of the SBS and JBSF algorithms based on real measurements. In addition, theoretical bounds are calculated in order to quantify the statistical performance of the algorithms. © 2014 IEEE.
Open Access
Fundamental limits and improved algorithms for linear least-squares wireless position estimation
(John Wiley & Sons, 2010-09-22) Guvenc, I.; Gezici, Sinan; Sahinoglu Z.
In this paper, theoretical lower bounds on performance of linear least-squares (LLS) position estimators are obtained, and performance differences between LLS and nonlinear least-squares (NLS) position estimators are quantified. In addition, two techniques are proposed in order to improve the performance of the LLS approach. First, a reference selection algorithm is proposed to optimally select the measurement that is used for linearizing the other measurements in an LLS estimator. Then, a maximum likelihood approach is proposed, which takes correlations between different measurements into account in order to reduce average position estimation errors. Simulations are performed to evaluate the theoretical limits and to compare performance of various LLS estimators.
Open Access
On the performance of linear least-squares estimation in wireless positioning systems
(IEEE, 2008-05) Gezici, Sinan; Güvenç, İ.; Sahinoğlu, Z.
A common technique for wireless positioning is to estimate time-of-arrivals (TOAs) of signals traveling between a target node and a number of reference nodes, and then to determine the position of the target node based on those TOA parameters. In determining the position of the target node from TOA parameters, linear or nonlinear least-squares (LS) estimation techniques can be employed. Although the linear LS techniques are suboptimal in general, they facilitate low-complexity position estimation. In this paper, performance of various linear LS techniques are compared, and suboptimality of the linear approach is quantified in terms of the Cramer-Rao lower bound (CRLB). Simulations are performed to compare the performance of the linear LS approaches versus the CRLBs for linear and nonlinear techniques. ©2008 IEEE.