Timestamping of IEEE 802.15.4a CSS Signals for Wireless Ranging and Time Synchronization

Dominicis, C. M. De; Pivato, P.; Ferrari, Paolo; Macii, David; Sisinni, Emiliano; Flammini, A.

doi:10.1109/tim.2013.2255988

Cited by 36 publications

(21 citation statements)

References 28 publications

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“…Both contributions can be determined in a straightforward manner by preliminary measurements, as described in [33] and [34], for what concerns the characterization of the timestamping mechanism and in [35] for the propagation delay.…”

Section: A Measurement Noise Covariance Matrix Rmentioning

confidence: 99%

An Event-Based Kalman Filter for Clock Synchronization

Giorgi

2015

IEEE Trans. Instrum. Meas.

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The distribution of a time reference has long been a significant research topic in measurement and different solutions have been proposed over the years. In this context, the design of servo clocks plays an important role to get better performances by smoothing the influence of noise sources affecting a synchronization system. A servo clock is asked to provide an adaptive and conservative measure of the time distance between the local clock and the time reference by minimizing, if possible, the energy consumption. In this paper, we propose a servo clock based on an efficient implementation of the Kalman filter (KF), called in the following event-based KF that allows to overcome drawbacks of existing KF-based servo clocks with furthermore a significant reduction of the computational cost. An in-depth analysis of the synchronization uncertainty has been reported to completely characterize the proposed solution; and finally, some guidelines on how to correctly initialize the KF are provided.Index Terms-Clock modeling, event-based systems, Kalman filtering, synchronization, uncertainty analysis.

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Section: A Measurement Noise Covariance Matrix Rmentioning

confidence: 99%

An Event-Based Kalman Filter for Clock Synchronization

Giorgi

2015

IEEE Trans. Instrum. Meas.

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“…Several enhancements have been studied and implemented in order to improve the overall accuracy in detecting the temporal position of the correlation peaks at the output of the matched filters [9]. The first improvement deals with the fact that uncertainty can be reduced by means of interpolation.…”

Section: A Timestamping Enhancementmentioning

confidence: 99%

“…As proposed in [9], the symbol timestamp is defined as the average of the estimated temporal positions of the correlation peaks of the four subchirps belonging to the same IEEE 802.15.4 symbol. The block diagram of this method is shown in Fig.…”

Section: A Timestamping Enhancementmentioning

confidence: 99%

“…It was shown in [9] that, through an algorithm based on correlation, chirp signals can be finely located on the time axis with uncertainties of the order of a few nanoseconds, which is much better than the basic resolution limit given by the receiver sampling interval. However, potential performances of the correlation approach for the IEEE 802.15.4 CSS physical layer can be jeopardized by interference from other radiofrequency (RF) sources, which may cause undesired random time shifts of correlation peaks, perceived as sudden variations of the time offset.…”

Section: Introductionmentioning

confidence: 99%

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Timestamp Validation Strategy for Wireless Sensor Networks Based on IEEE 802.15.4 CSS

Ferrari

Giorgi

Narduzzi

et al. 2014

IEEE Trans. Instrum. Meas.

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Network time distribution relies on timestamping, which is employed by local nodes to assign a time value to incoming timing packets. Clearly, any error affecting the timestamp has a direct impact on the final synchronization accuracy of the system. In wireless sensor networks (WSNs), impairments affecting the wireless physical layer are the primary cause of such timestamping errors, and it would be advantageous to flag suspect timestamp values before feeding them into a synchronization algorithm. This paper discusses a new strategy for validating timestamps in a WSN based on IEEE 802.15.4 chirp spread spectrum. The considered system employs physical-level timestamping, which generates one timestamp for each symbol belonging to a packet. Such set of timestamps is processed using a Kalman filter (KF) that compares them with predicted values, employing statistical thresholds referred to the KF innovation process. Experimental results obtained over a long observation period shows that even in a noisy environment with several interfering communication sources, the algorithm is able to detect untrusted timestamps

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“…The peak of the sinc-like function can be estimated by a parabolic interpolator since the peak itself has a parabolic-like shape near the maximum [13][14] [15].…”

Section: A Proposed Approachmentioning

confidence: 99%

Time of arrival estimation in power line communication systems for home smart grids

Ferrari

Flammini

Rinaldi

et al. 2013

2013 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication (ISPCS) Proceed

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This paper deals with time synchronization of devices attached to a smart grid, whose accuracy tightly depends on the accurate estimation of the Time of Arrival (ToA) of the synchronization related messages sent over the power line communication systems. Usually smart grids are quite complex "systems of heterogeneous systems": the aim of this paper is to suggest a ToA detection mechanism that can use to forward time synchronization to the "last mile" link and inside the end user home. In particular in this paper, the use of a chirp-based preamble, borrowed from wireless communications (which suffer from multipath and noise like in power line communication) is proposed and tested by means of simulations and real experiments with narrowband PRIME technology. The results show very interesting performance even with narrowband chirps: the standard deviation of the ToA estimation is always in the order of 150 ns, even with loaded electrical grids.

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Timestamping of IEEE 802.15.4a CSS Signals for Wireless Ranging and Time Synchronization

Cited by 36 publications

References 28 publications

An Event-Based Kalman Filter for Clock Synchronization

An Event-Based Kalman Filter for Clock Synchronization

Timestamp Validation Strategy for Wireless Sensor Networks Based on IEEE 802.15.4 CSS

Time of arrival estimation in power line communication systems for home smart grids

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