Extended Kalman Filter Channel Estimation for Line-of-Sight Detection in WCDMA Mobile Positioning

Abstract

<p/> <p>In mobile positioning, it is very important to estimate correctly the delay between the transmitter and the receiver. When the receiver is in line-of-sight (LOS) condition with the transmitter, the computation of the mobile position in two dimensions becomes straightforward. In this paper, the problem of LOS detection in WCDMA for mobile positioning is considered, together with joint estimation of the delays and channel coefficients. These are very challenging topics in multipath fading channels because LOS component is not always present, and when it is present, it might be severely affected by interfering paths spaced at less than one chip distance (closely spaced paths). The extended Kalman filter (EKF) is used to estimate jointly the delays and complex channel coefficients. The decision whether the LOS component is present or not is based on statistical tests to determine the distribution of the channel coefficient corresponding to the first path. The statistical test-based techniques are practical, simple, and of low computation complexity, which is suitable for WCDMA receivers. These techniques can provide an accurate decision whether LOS component is present or not.</p

Acoustic NLOS Identification Using Acoustic Channel Characteristics for Smartphone Indoor Localization

“…These methods are based on ranging statistics [16,17], consistency among multiple measurements [18], and channel characteristics [19,20,21,22]. However, for acoustic NLOS identification, the research is still in its infancy, and only little pioneering research work has been reported.…”

UKF-based channel estimation and LOS/NLOS classification in UWB wireless networks

“…In previous works, KF channel estimation techniques have efficiently been applied to delay estimation, especially when closely-spaced multipath echoes are present. For example, KF-based algorithms have been used in direct-sequence (DS) spread-spectrum code delay estimation with sub-chip spaced paths (Caffery & Stuber, 2000;Kim & Iltis 2002;Lakhzouri et al, 2003). For UWB systems, different channel estimation approaches for data detection purposes have been proposed in Cheng et al (2012);Fang et al (2012); Cheng et al (2010); Chen & Beaulieu (2010); Thomas et al (2010); Sato & Ohtsuki (2006).…”

NLOS Identification and Mitigation for Mobile Tracking

“…When tracking moving objects the Kalman filter (KF) is widely considered, and different tracking algorithms have been developed. Kalman filtering with consideration of NLOS mitigations has been investigated by many researchers [18][19][20][21][22][23]. In [18] Kalman filtering is used to reconstruct the NLOS-corrupted distance measurements by introducing a bias state variable.…”