scholarly journals An Efficient NLOS Errors Mitigation Algorithm for TOA-Based Localization

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1403
Author(s):  
Yanbin Zou ◽  
Huaping Liu
Keyword(s):  
Signal Propagation ◽  
Line Of Sight ◽  
Time Of Arrival ◽  
Error Statistics ◽  
The Core ◽  
Error Mitigation ◽  
Least Squares Optimization ◽  
Better Than ◽  
Localization Systems ◽  
Non Line Of Sight

In time-of-arrival (TOA) localization systems, errors caused by non-line-of-sight (NLOS) signal propagation could significantly degrade the location accuracy. Existing works on NLOS error mitigation commonly assume that NLOS error statistics or the TOA measurement noise variances are known. Such information is generally unavailable in practice. The goal of this paper is to develop an NLOS error mitigation scheme without requiring such information. The core of the proposed algorithm is a constrained least-squares optimization, which is converted into a semidefinite programming (SDP) problem that can be easily solved by using the CVX toolbox. This scheme is then extended for cooperative source localization. Additionally, its performance is better than existing schemes for most of the scenarios, which will be validated via extensive simulation.

scholarly journals Non-Line-of-Sight Error Mitigation in Wireless Communication Systems

2011 ◽  
Vol 1 ◽  
pp. 173-177
Author(s):  
Szu Lin Su ◽  
Yi Wen Su ◽  
Ho Nien Shou ◽  
Chien Sheng Chen
Keyword(s):  
Communication Systems ◽  
Hybrid Methods ◽  
Mobile Station ◽  
Base Stations ◽  
Superior Performance ◽  
Line Of Sight ◽  
Time Of Arrival ◽  
Angle Of Arrival ◽  
Error Statistics ◽  
Non Line Of Sight

When there is non-line-of-sight (NLOS) path between the mobile station (MS) and base stations (BSs), it is possible to integrate many kinds of measurements to achieve more accurate measurements of the MS location. This paper proposed hybrid methods that utilize time of arrival (TOA) at five BSs and angle of arrival (AOA) information at the serving BS to determine the MS location in NLOS environments. The methods mitigate the NLOS effect simply by the weighted sum of the intersections between five TOA circles and the AOA line without requiring priori knowledge of NLOS error statistics. Simulation results show that the proposed methods always give superior performance than Taylor series algorithm (TSA) and the hybrid lines of position algorithm (HLOP).

scholarly journals Target Localization via Integrated and Segregated Ranging Based on RSS and TOA Measurements

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 230 ◽  
Author(s):  
Slavisa Tomic ◽  
Marko Beko
Keyword(s):  
State Of The Art ◽  
Hybrid Approach ◽  
Critical Distance ◽  
Heuristic Approach ◽  
Target Localization ◽  
Line Of Sight ◽  
Time Of Arrival ◽  
Individual Measurement ◽  
New Approach ◽  
Non Line Of Sight

This work addresses the problem of target localization in adverse non-line-of-sight (NLOS) environments by using received signal strength (RSS) and time of arrival (TOA) measurements. It is inspired by a recently published work in which authors discuss about a critical distance below and above which employing combined RSS-TOA measurements is inferior to employing RSS-only and TOA-only measurements, respectively. Here, we revise state-of-the-art estimators for the considered target localization problem and study their performance against their counterparts that employ each individual measurement exclusively. It is shown that the hybrid approach is not the best one by default. Thus, we propose a simple heuristic approach to choose the best measurement for each link, and we show that it can enhance the performance of an estimator. The new approach implicitly relies on the concept of the critical distance, but does not assume certain link parameters as given. Our simulations corroborate with findings available in the literature for line-of-sight (LOS) to a certain extent, but they indicate that more work is required for NLOS environments. Moreover, they show that the heuristic approach works well, matching or even improving the performance of the best fixed choice in all considered scenarios.

scholarly journals Probability Weighting Localization Algorithm Based on NLOS Identification in Wireless Network

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Shixun Wu ◽  
Shengjun Zhang ◽  
Kai Xu ◽  
Darong Huang
Keyword(s):  
Base Station ◽  
Line Of Sight ◽  
Time Of Arrival ◽  
Probability Weighting ◽  
Localization Algorithm ◽  
Angle Of Arrival ◽  
Chi Square ◽  
Home Base ◽  
Angle Measurements ◽  
Non Line Of Sight

In this paper, a localization scenario that the home base station (BS) measures time of arrival (TOA) and angle of arrival (AOA) while the neighboring BSs only measure TOA is investigated. In order to reduce the effect of non-line of sight (NLOS) propagation, the probability weighting localization algorithm based on NLOS identification is proposed. The proposed algorithm divides these range and angle measurements into different combinations. For each combination, a statistic whose distribution is chi-square in LOS propagation is constructed, and the corresponding theoretic threshold is derived to identify each combination whether it is LOS or NLOS propagation. Further, if those combinations are decided as LOS propagation, the corresponding probabilities are derived to weigh the accepted combinations. Simulation results demonstrate that our proposed algorithm can provide better performance than conventional algorithms in different NLOS environments. In addition, computational complexity of our proposed algorithm is analyzed and compared.

scholarly journals NLOS Mitigation for TOA Location Based on a Modified Deterministic Model

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Hong Tang ◽  
Yongwan Park ◽  
Tianshuang Qiu
Keyword(s):  
Numerical Solution ◽  
Deterministic Model ◽  
The Other ◽  
Base Stations ◽  
Line Of Sight ◽  
Time Of Arrival ◽  
Wireless Location ◽  
Scale Factors ◽  
Measured Time ◽  
Non Line Of Sight

Wireless location becomes difficult due to contamination of measured time-of-arrival (TOA) caused by non-line-of-sight. In this letter, TOA measurements seen at base stations are adjusted by scale factors, and a modified deterministic model is built. An effective numerical solution is proposed to resolve the scale factors and mobile position. A simulation comparison of four algorithms indicates that the proposed algorithm outperforms the other three algorithms.

scholarly journals Analisis Performansi Multi User Detection pada Kanal NLOS untuk Sistem NOMA-VLC

2021 ◽  
Vol 9 (2) ◽  
pp. 482
Author(s):  
BIMA SURYA PRATAMA ◽  
NACHWAN MUFTI ADRIANSYAH ◽  
BRIAN PAMUKTI
Keyword(s):  
Wireless Communication ◽  
Visible Light ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Data Rate ◽  
Line Of Sight ◽  
Optical Wireless Communication ◽  
Optical Wireless ◽  
Better Than ◽  
Non Line Of Sight

ABSTRAKNon-orthogonal multiple access (NOMA), mulai diteliti untuk dapat digunakan sebagai teknik multiple access yang efektif pada jaringan 5G karena teknik ini dapat menghemat bandwidth modulasi. Pada penelitian ini, NOMA diterapkan untuk sistem downlink Visible Light Communivation (VLC). Kami telah melakukan analisis performansi Multi-User Detection (MUD) pada kanal propagasi Non-Line of Sight (NLOS) dengan mempertimbangkan efek reflektor dan efek bayangan (shadowing). Kami juga mempertimbangkan teknik MUD yang digunakan pada penelitian ini yaitu Succesive Interference Cancellation (SIC). Setelah simulasi yang ekstensif, kami menemukan bahwa dengan penerapan SIC sebagai MUD pada sistem NOMA-VLC lebih baik dibandingkan dengan tanpa NOMA. Selain itu, kami juga memperoleh peningkatan data rate sebesar 72 %.Kata kunci: VLC, NOMA, NLOS, MUD, Optical Wireless Communication. ABSTRACTNon-orthogonal multiple access (NOMA), began to be studied to be used as an effective multiple access technique on 5G networks because this technique can save modulation bandwidth. In this research, NOMA is applied to the Visible Light Communivation (VLC) downlink system. We have performed a Multi-User Detection (MUD) performance analysis on Non-Line of Sight (NLOS) propagation channels by considering the reflector and shadowing effects. We also consider the MUD technique used in this study, namely Successive Interference Cancellation (SIC). After extensive simulations, we found that the application of SIC as MUD to the NOMA-VLC system is better than without NOMA. In addition, we also achieve an increase in data rate of 72%.Keywords: VLC, NOMA, NLOS, MUD, Optical Wireless Communication.

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