TDOA, Frequency and Phase Offsets Estimation Taking Into Account Carrier Phase of Arrival

Janjic, Milos; Vukmirović, Nenad; Moulines, Éric

doi:10.13164/re.2017.1143

Cited by 3 publications

(8 citation statements)

References 16 publications

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“…These tasks are significantly less demanding than estimating classical CSI. For time shift estimation, we propose a noncoherent ML-type algorithm [6] due to the presence of relative phase offsets in the signals [27]. To estimate the residual constant phase offset, we propose a numerically efficient algorithm based on signal correlation.…”

Section: B the Contributions Of The Papermentioning

confidence: 99%

“…We assume that a m = 1 (∀m), so that the noise variance for a given channel models the propagation attenuation. We recall that a time shift always implies that there is a corresponding phase shift as well, since we deal with RF signals [27].…”

Section: Signal Modelmentioning

confidence: 99%

“…Furthermore, in the case of coherent localization, it necessitates spatial coherence within the scenario and could also benefit from enhanced time offset estimation accuracy. Coherent time estimation, under certain conditions, provides improvements over noncoherent estimation by a factor proportional to f c [27], [28]. As previously mentioned, our procedure utilizes noncoherent algorithms for time shifts due to the presence of relative phase offsets in the signals.…”

Section: Localizationmentioning

confidence: 99%

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Over-the-Air Synchronization of Time, Phase and Frequency in a Distributed Receiving System

Janjić,

Vukmirović,

Erić

et al. 2023

IEEE Access

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This paper addresses over-the-air synchronization of two distributed receivers connected to a fusion center via digital links. We distinguish between received signals' synchronization and receiving channels' synchronization. The applications are digital receive beamforming (BF) and radio source localization, respectively. We introduce the system and signal models and propose a synchronization procedure. The scheme for signal synchronization includes estimating and compensating for the instantaneous phase and time offsets between the received user signals. This is achieved by utilizing wideband and narrowband pilots sent by a beacon transmitter, along with a wideband preamble sent by the user transmitter. Optionally, the scheme allows for equalization of the user signal, employing a narrowband pilot signal sent by the user transmitter. For channel synchronization, the procedure involves estimating and compensating for the instantaneous phase and time offsets between the receiving channels using pilot signals sent by the beacon transmitter. We assume variable frequency and constant time offsets during the observation interval. Additionally, we propose a novel adaptive algorithm for instantaneous phase offset estimation. We demonstrate the performance of the synchronization procedure and the proposed algorithms through Monte Carlo simulations and experiments using USRPs (Universal Software Radio Peripheral). With a 20 dB signal-to-noise ratio and realistic frequency offset amplitude and dynamics, the 0.9-quantiles for time estimation error and instantaneous phase estimation error are one 20th of the sampling interval and 10 degrees, respectively. The total error is reduced almost to the noise-only error.INDEX TERMS Distributed receiving system, instantaneous phase offset estimation, over-theair synchronization, radio source localization, receive digital beamforming, time offset estimation, USRP.

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Section: B the Contributions Of The Papermentioning

confidence: 99%

Section: Signal Modelmentioning

confidence: 99%

Section: Localizationmentioning

confidence: 99%

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Over-the-Air Synchronization of Time, Phase and Frequency in a Distributed Receiving System

Janjić,

Vukmirović,

Erić

et al. 2023

IEEE Access

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“…In [ 21 ], it has been found that the estimation accuracy based on TDoA could significantly be increased by exploiting the carrier phase of arrival. This suggests that the localization accuracy could also considerably benefit from the carrier phases in spatially coherent settings.…”

Section: Introductionmentioning

confidence: 99%

Performance Limits of Direct Wideband Coherent 3D Localization in Distributed Massive MIMO Systems

Vukmirović

Moulines

Djurić

2021

Sensors

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We address the accuracy of wideband direct position estimation of a radio transmitter via a distributed antenna array in 5G cellular systems. Our derivations are based only on the presence of spatially coherent line-of-sight (LoS) signal components, which is a realistic assumption in small cells, especially in the mmWave range. The system model considers collocated time and phase synchronized receiving front-ends with antennas distributed in 3D space at known locations and connected to the front-ends via calibrated coaxial cables or analog radio-frequency-over-fiber links. Furthermore, the signal model assumes spherical wavefronts. We derive the Cramér-Rao bounds (CRBs) for two implementations of the system: with (a) known signals and (b) random Gaussian signals. The results show how the bounds depend on the carrier frequency, number of samples used for estimation, and signal-to-noise ratios. They also show that increasing the number of antennas (such as in massive MIMO systems) considerably improves the accuracy and lowers the signal-to-noise threshold for localization even for non-cooperative transmitters. Finally, our derivations show that the square roots of the bounds are two to three orders of magnitude below the carrier wavelength for realistic system parameters.

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“…In [9,10], it was shown that the accuracy of TDoA estimation could be significantly increased by exploiting the carrier phase of arrival. Since direct localization is implicitly based on TDoAs, this suggests that the localization accuracy could also benefit significantly from exploiting the carrier phases in spatially-coherent scenarios.…”

Section: Introductionmentioning

confidence: 99%

Direct Wideband Coherent Localization by Distributed Antenna Arrays

Vukmirović

Moulines

Janjic

et al. 2019

Sensors

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We address wideband direct coherent localization of a radio transmitter by a distributed antenna array in a multipath scenario with spatially-coherent line-of-sight (LoS) signal components. Such a signal scenario is realistic in small cells, especially indoors in the mmWave range. The system model considers collocated time and phase synchronized receiving front-ends with antennas distributed in 3D space at known locations connected to the front-ends via calibrated coaxial cables or analog radio frequency over fiber links. The signal model assumes spherical wavefronts. We propose two ML-type algorithms (for known and unknown transmitter waveforms) and a subspace-based SCM-MUSIC algorithm for wideband direct coherent position estimation. We demonstrate the performance of the methods by Monte Carlo simulations. The results show that even in multipath environments, it is possible to achieve localization accuracy that is much better (by two to three orders of magnitude) than the carrier wavelength. They also suggest that the methods that do not exploit knowledge of the waveform have mean-squared errors approaching the Cramér–Rao bound.

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TDOA, Frequency and Phase Offsets Estimation Taking Into Account Carrier Phase of Arrival

Abstract: Abstract. This paper deals with estimation of time difference of arrival (TDOA)

Cited by 3 publications

References 16 publications

Over-the-Air Synchronization of Time, Phase and Frequency in a Distributed Receiving System

Over-the-Air Synchronization of Time, Phase and Frequency in a Distributed Receiving System

Performance Limits of Direct Wideband Coherent 3D Localization in Distributed Massive MIMO Systems

Direct Wideband Coherent Localization by Distributed Antenna Arrays

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