Entropy-Based TOA Estimation and SVM-Based Ranging Error Mitigation in UWB Ranging Systems

Abstract

The major challenges for Ultra-wide Band (UWB) indoor ranging systems are the dense multipath and non-line-of-sight (NLOS) problems of the indoor environment. To precisely estimate the time of arrival (TOA) of the first path (FP) in such a poor environment, a novel approach of entropy-based TOA estimation and support vector machine (SVM) regression-based ranging error mitigation is proposed in this paper. The proposed method can estimate the TOA precisely by measuring the randomness of the received signals and mitigate the ranging error without the recognition of the channel conditions. The entropy is used to measure the randomness of the received signals and the FP can be determined by the decision of the sample which is followed by a great entropy decrease. The SVM regression is employed to perform the ranging-error mitigation by the modeling of the regressor between the characteristics of received signals and the ranging error. The presented numerical simulation results show that the proposed approach achieves significant performance improvements in the CM1 to CM4 channels of the IEEE 802.15.4a standard, as compared to conventional approaches.

A New Elliptical Model for Device-Free Localization

“…There are six popular algorithms in DFL systems: (1) the fingerprint (FP) [ 12 , 13 ]; (2) the support vector machine (SVM) [ 14 , 15 ]; (3) radio tomographic imaging (RTI) [ 11 , 16 , 17 , 18 , 19 ]; (4) the particle filter (PF) [ 6 , 20 ]; (5) the Bayesian system [ 16 , 21 ]; and (6) compressed sensing (CS) [ 22 , 23 ]. Of these algorithms, the RTI-based DFL system has seen much research in recent years and is the focus of this paper.…”

WUB-IP: A High-Precision UWB Positioning Scheme for Indoor Multiuser Applications

“…At first, we set a threshold, which ensure that desired signal pulses exceed threshold in most cases, and the noise can rarely exceed. As analyzed in [19], the threshold can be set based on the variance of received noise, which is given by…”

“…Unfortunately, these two approaches are inefficient for UWB pulse-based ranging in a multi-user application, especially in dense multi-path conditions. In this regard, a more efficient scheme for UWB multiple access is proposed in [18] and [19], namely, waveform division multiple access (WDMA). In WDMA-UWB, orthogonal waveforms are used for multiple access by using appropriate waveform design, which releases the limitations to communication and spectrum efficiency.…”

IEEE 802.15.4 ZigBee-Based Time-of-Arrival Estimation for Wireless Sensor Networks

“…The accuracy of distance measurement using wireless network technology is a function of the signal bandwidth; using broad bandwidth is the most fundamental approach for achieving higher accuracy [ 6 ]. Hence, among the above-mentioned communication systems, UWB-based positioning technology with a bandwidth of 500 MHz has seen significant development [ 7 , 8 , 9 , 10 , 11 , 12 ]. According to a recent study, UWB-based positioning technology achieves highly accurate performance down to a few centimeters.…”