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In this paper we present a proof-of-concept for an hydro acoustic fish-tag position estimation and tracking system. In our field-tested concept, a formation of Unmanned Surface Vehicles (USV) creates a mobile array of low-cost hydro acoustic fish-tag receivers. The array of receivers is able to estimate fish-tag locations and follow the fish on open waters, significantly increasing capabilities as...
The paper deals with the estimation method of a carrier and time of arrival by chirp-like phase-coded sequence. The developed estimation method of the carrier and time of arrival is suitable for primary synchronization upon signal detection in phase and frequency modulation modems. This method is of less computational complexity relative to the realization of matched filter assembly. To implement...
In this paper, we present the baseband receiver design for IEEE 802.11ah. We study several key receiver algorithms, including coarse frequency offset estimation and coarse timing synchronization, fine frequency offset estimation, fine timing synchronization, channel estimation and MIMO equalization. For channel estimation, we propose to use decoded SIG field to improve its estimation. To further improve...
In this paper, we propose a positioning system using a time-synchronized wireless network that can achieve high positioning accuracy without being dependent on any global positioning system (GPS) devices with cm-level accuracy as the main goal and objective. The proposed system utilizes time of arrival (ToA) method to estimate the target's position. Based on the results, we can achieve time synchronization...
In the paper, operation algorithms of the N-OFDM modem for channels with the Additive White Gaussian Noise (AWGN) are considered. The algorithms are based on the Hartley transform under the optimal demodulation by the estimation of the received signals amplitudes using the Cauchy method. The experimental results for interference immunity estimation are provided for different values of spacing frequencies...
A novel blind time-frequency joint synchronization based on the cyclostationary of orthogonal frequency division multiplexing with offset quadrature amplitude modulation (OFDM/OQAM) systems is conceived in multipath channels conditions. The cyclic cumulants of OFDM/OQAM signals are derived firstly, symbol timing offset (STO) and carrier frequency offset (CFO) are estimated by employing two groups...
In industrial applications synchronized sensor nodes are vital for many tasks like multi parameter sampling of complex machinery behavior. The wirelessly connected nodes are usually synchronized to a base station. Therefore, frequency or period estimation of the reference clock is a key issue for all connected tasks like sampling, localization or applying energy optimized communication protocols....
Although a number of asynchronous physical-layer network coding (PNC) schemes have been proposed, synchronous PNC may still be preferred for its simplicity. In this paper we propose a new symbol-level synchronization scheme which reduces the misalignment to less than one hardware clock cycle period. In addition, we prototype the proposed scheme on the Universal Software Radio Peripheral (USRP) platform...
High-speed, image-sensor visible light communication using rolling shutter has been studied. Symbol synchronization method by sequential estimation is applied to the line scan sampling using the rolling shutter of the image sensor and achievable symbol rate is simulated. Over 1400 symbols per second can be realized by the symbol synchronization at the frame rate of 30 fps with a QVGA screen. Acceptable...
Multi-channel speech enhancement algorithms rely on a synchronous sampling of the microphone signals. This, however, cannot always be guaranteed, especially if the sensors are distributed in an environment. To avoid performance degradation the sampling rate offset needs to be estimated and compensated for. In this contribution we extend the recently proposed coherence drift based method in two important...
Phase-locked loops (PLLs) are doubtless the most popular synchronization technique in the power converters. Almost all proposed PLL structures known in literature are inherently nonlinear and can be linearized as second order linear time invariant system. Nonlinear nature of PLLs degrades their performances, and question arises if there exist an enhanced PLL structure that would have superior performances...
Large scale distributed simulation should be well planned before the execution, since applying unnecessary hardware only wastes our time and money. On the other side, we need enough hardware to achieve an acceptable performance. Thus, it is considerable to estimate the performance of a large scale distributed simulation before the execution. Such an estimation also improves the efficiency of the applied...
A model of input data buffering in measuring systems is developed. The authors obtained the formulae to determine the following time intervals: between two successive transactions to signal source, two successive transactions to signal receiver, between transactions on data receiving and generation, between transactions on data generation and receiving. It is shown that an adequate model of the buffered...
This paper proposes a filter-based distributed protocol to realize time synchronization under time-varying clock parameters. The proposed protocol is derived from a first-order controller and is fully distributed, meaning that by relying merely on its local clock readings and reading announcements from its neighbouring sensor nodes, each node in WSNs can dynamically update its virtual clock and bound...
The proliferation of estimation algorithms for Phasor Measurement Units (PMUs) makes performance analysis and comparison between different techniques a challenging task. This paper presents a testbed conceived to perform a flexible and accurate characterization of different estimation algorithms in various testing conditions reported in the IEEE Standard C37.118.1-2011 and its Amendment C37.118.1a-2014...
Development of synchronized phasor measurements is one of the most significant developments in the area of power systems in recent times. A lot of research is being conducted in their applications and optimal placement as well. However, more efforts are needed to develop models of Phasor Measurement Units (PMUs) which can be directly utilized in power system simulations without the need for spending...
A joint timing offset (TO) and frequency offset (FO) estimation method based on Radon-Wigner transform (RWT) is first proposed for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems. The result shows that the timing and frequency synchronization performance of the proposed method are both better than the Schmidl & Cox method and fractional Fourier transform (FrFT) algorithm...
In this paper a novel method to improve theWireless Sensor Network synchronization process by introducing networkcoded messages is proposed. The presented technique outweighs the effects of the channel’s outage probability by employing the available data to refine the estimates of the pairwise clock offsets. By virtue of the proposed technique, the mean square error of the estimator is significantly...
Microphone array for high-quality audio recording has been realized by dedicated devices. But lack of portability and high cost prevent such system being widely adopted. Today's commercial-off-the-shelf (COTS) smartphones are relatively more convenient for audio recording. However, in order to estimate the target's direction of arrival (DOA), several asynchronous receivers (smartphones) must be precisely...
We present new methods of simultaneously estimating camera geometry and time shift from video sequences from multiple unsynchronized cameras. Algorithms for simultaneous computation of a fundamental matrix or a homography with unknown time shift between images are developed. Our methods use minimal correspondence sets (eight for fundamental matrix and four and a half for homography) and therefore...
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