1. Abstract While many technologies currently available for fixed broadband wireless can only provide line of sight (LOS) coverage, the technology behind WiMAX has been optimized to provide excellent non line of sight (NLOS) coverage. WiMAX’s advanced technology provides the best of both worlds – large coverage distances of up to 50 kilometers under LOS conditions and typical cell radii of up t...

This paper addresses the problem of mobile sensor localization and tracking in an obstructed environment. To solve this problem, a combination of three approaches is proposed: a nonlinear Kalman Filter to estimate the mobile position, a sub filter used jointly with the nonlinear filter to estimate the bias due to the Non-Line Of Sight (NLOS) effect and a low complexity method for Line Of Sight ...

An effective geometrical method which can locate a source based on the time-of-arrival (TOA) measurements and the floor plan information is proposed in simple non-line-of-sight (NLOS) indoor environment where the multiplebound scattering signal paths can be ignored. The novelty of our work resides in converting the NLOS problem into line-of-sight (LOS) problem based on the virtual stations (VSs...

The Non-Line of Sight (NLOS) problem is the major drawback for accurate localization within Ultra-Wideband (UWB) sensor networks. In this article, a comprehensive overview of the existing methods for localization in distributed UWB sensor networks under NLOS conditions is given and a new method is proposed. This method handles the NLOS problem by an NLOS node identification and mitigation appro...

SUMMARY A novel method is proposed to track the position of MS in the mixed line-of-sight/non-line-of-sight (LOS/NLOS) conditions in cellular network. A first-order markov model is employed to describe the dynamic transition of LOS/NLOS conditions, which is hidden in the measurement data. This method firstly uses modified EKF banks to jointly estimate both mobile state (position and velocity) a...

In this paper, a novel method for sensor node localization under mixed line-of-sight/non-line-of-sight (LOS/NLOS) conditions based on second order cone programming (SOCP) is presented. SOCP methods have, hitherto, not been utilized in the node localization under mixed LOS/NLOS conditions. Unlike semidefinite programming (SDP) formulation, SOCP is computationally efficient for resource constrain...

This paper studies the problem of tracking a mobile device in mixed line-of-sight (LOS) and non-line-of-sight (NLOS) conditions. NLOS error is assumed to be Gaussian with unknown mean and variance. An adaptive Rao-Blackwellized particle filter (RBPF) is proposed for mobile tracking in such scenarios. An extended Kalman filter is used to approximately estimate the mobile state, and the particle ...

A major concern of cellular and PCS-based wireless location systems is the effect of the harsh propagation environment, particularly non-line-of-sight (NLOS) propagation. In order to improve location accuracy under such conditions, this paper proposes a novel location technique that estimates the true, or line-of-sight (LOS), ranges based on NLOS range measurements. The algorithms, designed for...

Usually the capacity of multiple-input multiple-output (MIMO) wireless communication channels is evaluated under the assumption of fixed signal to noise (SNR) scenario. In this paper the impact of temporal SNR variation on capacity of MIMO wireless channels in urban microcells is considered. Results based on data measured in line of sight (LOS) and non line of sight (NLOS) propagation scenarios...

Tracking a mobile node using a wireless sensor network under non-line of sight (NLOS) conditions, has been considered in this work, which is of interest to indoor positioning applications. A hybrid of time difference of arrival (TDOA) and angle of arrival (AOA) measurements, suitable for tracking asynchronous targets, is exploited. The NLOS biases of the TDOA measurements and the position and v...