• Journal of IKEEE
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• v.24 no.1
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• pp.248-253
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• 2020

This paper proposed PTP(Precision Time Protocol) management node-based time synchronization error detection and recovery system. The proposed system is to maintain the preciseness of time synchronization under time synchronization error situations on IEEE 1588-based network environment. To demonstrate the proposed time synchronization error detection and recovery system, PTP implemented EVM(Evaluation Module)-based experiments were performed. As a results of the experiments, it is shown that the proposed system effectively maintains the preciseness of time synchronization under time synchronization error situations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.2013-2022
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• 1996

Cyclic Codes can be used for burs(or time slot) synchronization as well as error detection as that the overhead bits of the burst, which would be nessary to seperate burst synchronization and error detection systems, may be eliminated. In this paper a new method for combined burst synchronization and error detection is proposed which requires CRC decoding once only, while the previous method which inspects channel error after searching for burst synchronization requeires CRC decoding twice. The proposed method has the advantage of simple implementation and reducing processing time over the previous one, still showing the same detection perfdormance. It may occur that a burst different from the actually transmitted one is falsely accepted in the presence of channel errors. The exact expression for the false acceptance probability is newly presented through a simple derivation basied on the fact that it is determined by channel errors but not by detection methods.

• Journal of electromagnetic engineering and science
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• v.5 no.1
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• pp.26-30
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• 2005

It is important to know phase offsets of PN(Pseudo Noise) sequences in spread spectrum communications since the acquisition is equivalent to making a phase offset between a receiving PN sequence and a PN sequence of local PN generator be identical. In this paper, a phase offset enumeration method for PN sequences with error detection, and its application to the synchronization are proposed. The phase offset enumeration for an n-tuple PN sequence and its error detection are performed when one period of the sequence is received. Once the phase offset of the receiving sequence is calculated, we can easily accomplish the synchronization by initializing shift registers of a local PN generator according to the phase offset value. The mean acquisition time performance of the proposed scheme was derived analytically. Since this synchronization scheme can be realized by using simple circuit and acquires very rapid acquisition in high SNR but shows performance degradation in low SNR, it can be especially useful in indoor and office environments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.2
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• pp.141-154
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• 2013

The technology of precise time-synchronization between signal receive devices for separation distance operation can be a key point for the technology with TDoA-based system. We propose a new method for the higher accuracy of system's time-synchronization in this paper, which uses OCXO and DPLL with high accuracy to achieve phase synchronization at 1 pps (pulse per second) of signal. And the method receive time value from a GPS satellite. Essentially, the performance of GPS with high accuracy refers to long-term frequency stability for its reliability. As per the characteristic, as the GPS timing signals are synchronized continuously, the accuracy of time-synchronization gets improved proportionally. Therefore, if the time synchronization is accomplished, the accuracy of the synchronization can be up to 0.001 ppb (part per billion). Through the improved accuracy of the time-synchronization, the measurement error of TDOA-based location detection technology is evaluated. Consequently, we verify that TDoA-based location measurement error can be greatly improved via using the improved method for time-synchronization error.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.272-274
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• 2005

In this paper, we analyses transmission performance of communication security(COMSEC) bit synchronization information over the single channel found and airborne radion system in variable message format system. Experimental results demonstrate the robust characteristics of the COMSEC bit synchronization information in $10^{-1}\sim10^{-5}$ of bit error channel and the relationship of time duration of bit synchronization and probability of synchronization detection.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.7
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• pp.443-446
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• 2005

In this paper, we analyses transmission performance of communication security(COMSEC) bit synchronization information over the single channel ground and airborne radion system in variable message format system. Experimental results demonstrate the robust characteristics of the COMSEC bit synchronization information in 10-1 $\~$ 10-5 of bit error channel and the relationship of time duration of bit synchronization and probability of synchronization detection.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.582-591
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• 2010

Probabilistic modeling and analysis of correlation metrics have been receiving considerable interest for a long period of time because they can be used to evaluate the performance of communication receivers, including satellite broadcasting receivers. Although differential correlators have a simple structure and practical importance over channels with severe frequency offsets, closedform expressions for the output distribution of differential correlators do not exist. In this paper, we present detection error probability expressions for frame synchronization using differential correlation, and demonstrate their accuracy over channel parameters of practical interest. The derived formulas are presented in terms of the Marcum Q-function, and do not involve numerical integration, unlike the formulas derived in some previous studies. We first determine the distributions and error probabilities for single-span differential correlation metric, and then extend the result to multispan differential correlation metric with certain approximations. The results can be used for the performance analysis of various detection strategies that utilize the differential correlation structure.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.6
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• pp.1487-1495
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• 2013

Time synchronization is a prerequisite in wireless sensor network applications such as object tracking, consistent state update, duplication detection, and temporal order delivery. This paper analyze time synchronization accuracy of pair-wise time synchronization algorithm which is a typical time synchronization model of time synchronization method in wireless sensor networks. In addition, the analyzed results are verified by simulations. These results can be utilized for performance improvement or development of time synchronization in wireless sensor networks.

• KIPS Transactions on Computer and Communication Systems
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• v.2 no.1
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• pp.7-14
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• 2013

Presently, there are many different technologies used for position detection. However, as signal-receiving devices operating in different locations must detect the precise position of objects located at long distances, it is essential to know the precise time at which an object's or a user's terminal device sends a signal. For this purpose, the existing time of arrival (ToA) technology is not sufficiently reliable, and the existing time difference of arrival (TDoA) technology is more suitable. If a TDoA-based electric surveillance system and other tracking devices fail to achieve precise time-synchronization between devices with separation distance operation, it is impossible to obtain correct TDoA values from the signals sent by the signal-receiving devices; this failure to obtain the correct values directly affects the location estimation error. For this reason, the technology for achieving precise time synchronization between signal-receiving devices in separation distance operation, among the technologies previously mentioned, is a core technology for detecting TDoA-based locations. In this paper, the accuracy of the proposed time synchronization and the measurement error in the TDoA-based location detection technology is evaluated. The TDoA-based location measurement error is significantly improved when using the proposed method for time-synchronization error reduction.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.581-584
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• 2003

It is important to know phase offsets of PN (Pseudo Noise) sequences in spread spectrum communications since the acquisition is equivalent to make a phase offset between a receiving PN sequence and a PN sequence of local PN generator be identical. In this paper, a phase offset enumeration method for PN sequences with error detection, and its application to the synchronization are proposed. The phase offset enumeration far an n-tuple PN sequence and its error detection are performed when one period of the sequence is received. Once the phase offset of the receiving sequence is calculated, we can easily accomplish the synchronization by initializing shift registers of a local PN generator according to the phase offset value. The mean acquisition time of the proposed synchronization method is derived analytically, and we see that the method acquires very fast acquisition in the high SNR (Signal-to- Noise Ratio) environment.