• Journal of Advanced Navigation Technology
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• v.12 no.4
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• pp.341-349
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• 2008

In this paper the Coefficient Tracking Synchronization Algorithm is proposed for the compensation and the suitability of the fast channel fluctuation OFDM in the WAVE(Wireless Access in Vehicular Environments) system. The in progress of standardization WAVE process, IEEE802.11p's physical layer is considered on the coexistence of fading and Frequency offset of OFDM channel to find the system performance ability and the comparing examination which is taken on the proposed method of Coefficient Tracking Synchronization Algorithm and the performance efficiency. Through the simulation result we also can see that the proposed system improves the channel estimation ability and offers an extra efficiency if compared to the existing method.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.118-125
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• 2008

In this paper, an efficient frequency offset synchronization structure for OFDM(Orthogonal Frequency Division Multiplexing) is proposed. Conventional CORDIC(Coordinate Rotation Digital Computer) algorithm for frequency offset synchronization utilizes two CORDIC hardware i.e., one is vector mode for phase estimation, the other is rotation mode for compensation. But proposed structure utilizes one CORDIC hardware and divider. Through simulation, it is shown that hardware implementation complexity is reduced compared with conventional structures. The Verilog-HDL coding and front-end chip implementation results for the proposed structure show 22.1% gate count reduction comparison with those of the conventional structure.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7C
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• pp.706-712
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• 2006

In this letter, we propose a compact CORDIC processor for implementation of carrier frequency synchronization block in an OFDM (Orthogonal Frequency Division Multiplexing) system. The compact CORDIC processor is proposed by using inherenct properties of an OFDM system for estimation and compensation of carrier frequency offset, and is composed of a compact CORDIC preprocessor and a compact CORDIC processor. The compact CORDIC preprocessor plays a role of normalizing input signal efficiently, and the compact CORDIC processor is proposed to perform the vectoring mode and rotational mode jointly in CORDIC operation for carrier frequency synchronization. It is shown by FPGA implementation that the proposed compact CORDIC processor can achieve better performance with a significantly reduced hardware complexity than the conventional CORDIC approach.

• Journal of Communications and Networks
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• v.12 no.6
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• pp.533-543
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• 2010

This paper proposes an orthogonal frequency division multiplexing (OFDM) waveform for the forward link of a fixed broadband satellite system. We focus on the synchronization tasks in the receiver. Our objective is to minimize the required overhead, in order to improve the spectral efficiency with regard to a single carrier waveform system. A non pilot aided algorithm is used for fine synchronization. It is preceded by a coarse synchronization stage, which relies on a limited overhead (short cyclic prefix associated to some pilots). The performance of the proposed receiver is assessed through simulation results.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1697-1700
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• 2002

In this paper, we propose a new frame structure and frame synchronization algorithm for OFDM burst mode transmission. On the contrary to conventional OFDM symbol based methods, the proposed preamble for symbol frame synchronization is designed independently in time domain in arbitrary length and is placed at the beginning of the frame. The proposed frame synchronization algorithm by using the preamble is working independent of frequency offset and robust to serious channel environment.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.41-44
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• 2000

In this paper, an improved timing synchronization method for OFDM system is proposed. In multipath fading channels, timing offset estimation algorithm based on simple correlation metric can cause inter-symbol interference (ISI). The proposed algorithm promises accurate timing offset estimation, which can be achieved by simple windowing. The estimation errors in several multipath channels are evaluated in computer simulations.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.123-124
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• 2007

In this paper a comparison of several coarse time synchronization(CTS) algorithms for OFDM is presented. The goal of a CTS is to achieve a timing estimate that avoids IST in the receiver. Five coarse timing estimation algorithms are examined and their performances are compared associated with hardware complexity. Simulations has been performed for DVB-T 2K system in thee different channels.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.1
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• pp.69-74
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• 2003

In this paper, we propose the synchronization recovery algorithm which is suitable to wireless Multimedia of wireless channel situation which is being used OFDM signaling method. The basic of the suggested clock synchronization. restoration Algorithm is to getting the shock response of channel or getting the multipath strength profile through IFTT after the getting the frequency, response of deducted channel from channel deducted of receiver and to trace the location in the channel energy concentrated area of timing area. And it also analysis the start point of 64-QAM and 16-QAM if the sampling clock offset has the sample of ${\pm}$ 1-3, and we identified the occurance of performance deterioration when occures more than 2 samples of offset to compare with star point and BER performance in optimum sampling point result of BER performance checking, and we know that the recovery algorithm proposed algorithm also provide excellent synchronization characteries under frequency, selecting fading channel as result of simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.1C
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• pp.92-98
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• 2005

In this paper, blind synchronization algorithm is developed for estimating jointly timing and frequency offset of OFDM system. The proposed estimator exploits the second-order cyclostationarity of received signals, and then uses the information of symbol timing and carrier frequency offset appeared in the cyclic correlation. As a bling estimator, the information of impulse response of channel and training symbols are not required. The performance of the proposed method is consistent in spite of channel conditions in mean squre error sense, and simulation results prove it. For more accurate estimaion, the method that averages cyclic correlation is applied. In this case, the performance of averaging method is better.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.8A
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• pp.815-820
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• 2008

Carrier frequency offset (CFO) is one of the most important problems in an orthogonal frequency division multiplexing (OFDM) system, which seriously degrades the performance of the systems due to its time-variant behavior. In this paper, the performance of a pilot-assisted fine CFO estimator in OFDM-based mobile WiMAX systems is analyzed. Analytical closed-form expression of the mean square error (MSE) of the post-FFT based CFO synchronization scheme is reported for time-variant fading channels. Taking into account the frame structure of the IEEE802.16e standard, simulation results are used to verify the theoretical analysis developed in this paper.