Won-Gi Jeon

Chung-Ang University, Seoul, Seoul, South Korea

Are you Won-Gi Jeon?

Claim your profile

Publications (30)20.11 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we propose a detection method for Digital Radio Mondiale (DRM) Plus suitable for hybrid mode broadcasting which services both DRM Plus and analog FM within the same frequency band. The guard-interval correlation method of Orthogonal Frequency Division Multiplexing (OFDM) is good for DRM Plus signal detection, but the possibility for false alarm increases when FM signal is received. The proposed method includes a reference block in the guard-interval correlation which increases the identification rate of weak DRM Plus signals and decreases the possibility of false alarm when analog FM is received. The performance of the proposed method is verified through simulations.
    Journal of Broadcast Engineering. 11/2013; 18(6).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, BER(Bit Error Ratio) performances of the TransferJet system, which is the standard of a close proximity inductive wireless communication system, are presented and analyzed. Comparing to other wireless communication systems, the TransferJet system has some advantages such as short communication range(i.e., high security in the wireless communication environments), fewer effects of multipath distortion, and higher transmission rate. In order to demodulate the received signal, either SC(Soft-decision Combining) or HC(Hard-decision Combining) can apply to the despreader and demodulator of the receiver. When the spreading factor is more than 4, the SC scheme approximately has a minimum signal-to-noise ratio gain of 2 dB over the HC scheme. Moreover, from simulation results, we can conclude that the quantization bits of 3 bits are an optimum value for the SC scheme in the TransferJet system since the 3-bit quantization achieves nearly the performance as that attained by double-precision floating-point.
    The Journal of Korea Navigation Institute. 10/2012; 16(5).
  • [Show abstract] [Hide abstract]
    ABSTRACT: This letter addresses the edge effect on a windowed discrete Fourier transform (WDFT)-based channel estimator for orthogonal frequency division multiplexing (OFDM) systems with virtual carriers in non-sample spaced channels and derives a sufficient condition to reduce the edge effect. Moreover, a modified WDFT-based channel estimator with multi-step linear prediction as an edge effect reduction technique is proposed. Simulation results show that it offers around 5dB signal-to-noise ratio (SNR) gain over the conventional WDFT-based channel estimator at bit error rate (BER) of 10-3.
    IEICE Transactions on Fundamentals of Electronics Communications and Computer Sciences 01/2010; 93-A:1375-1378. · 0.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, the bit-error-ratio (BER) performances of Digital Radio Mondiale Plus (DRM+) system which stand for the European standard to bring analogue FM radio to digital radio in Band-II(30-170 MHz) are evaluated under multipath fading channel models used in Band-II and the adjacent channel interference (ACI) caused by FM signal. From the simulation results, the DRM+ system shows robust performances under time-varying channel environments even though the speed of a vehicle is equal to 300km/h. And it is shown that the frequency diversity, determined by delay spread of multipath fading channel, increases the coding gain of the DRM+ system with an increase of delay spread. In addition, to guarantee the BER performance of 10-4 for DRM+ system with ACI due to FM signal, the simulation results show that the desired signal-to-ACI power ratio must be more than -30 dB when the carrier frequency distance is 150 kHz.
    The Journal of Korea Navigation Institute. 01/2010; 14(1).
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we propose a new digital duplexing scheme, called synchronous digital duplexing (SDD), which can increase data efficiency and flexibility of resource by transmitting uplink signal and downlink signal simultaneously in wireless communication. In order to transmit uplink and downlink signals simultaneously, the proposed SDD obtains mutual information among subscriber stations (SSs) with a mutual ranging symbol. This information is used for selection of transmission time, decision on cyclic suffix (CS) insertion, determination of CS length, and re-establishment of FFT starting point. It is shown that in terms of efficiency and flexibility the proposed SDD is better equipped as a duplexing scheme for indoor wireless environments than conventional time division duplexing (TDD) and frequency division duplexing (FDD).
    Vehicular Technology Conference, 2009. VTC Spring 2009. IEEE 69th; 05/2009
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we propose mitigation techniques using time-domain shortening filter (TSF) and frequency-domain shortening filter (FSF) to overcome inter-block interference (IBn and inter-carrier interference (ICn due to the time difference of arrival (TDoA) and carrier frequency offset (CFO) between downlink and uplink signals from access point (AP) and subscriber station (SS) in synchronous digital duplexing (SDD)/orthogonal frequency division multiple access (OFDMA) systems for indoor wireless communication. The proposed TSF and FSF maximize SIR for shortening in time (SIRST) and SINR for shortening in frequency (SINRSF), respectively, by using channel impulse responses and timing information among stations, obtained from mutual ranging procedure. It is verified by computer simulation that the proposed TSF and FSF reduce effectively the effects of IBI and ICI in the SDD/OFDMA systems.
    The Journal of Korea Information and Communications Society. 01/2009; 34(8C).
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we propose a new digital duplexing scheme, called synchronous digital duplexing (SDD), which can increase data efficiency and flexibility of resource by transmitting uplink signal and downlink signal simultaneously in wireless communication. In order to transmit uplink and downlink signals simultaneously, the proposed SDD obtains mutual information among subscriber stations (SSs) with a mutual ranging symbol. This information is used for selection of transmission time, decision on cyclic suffix (CS) insertion, determination of CS length, and re-establishment of FFT starting point.
    IEICE Transactions on Communications 01/2009; 92-B:2492-2495. · 0.31 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we propose a subcarrier allocation method and a composite linear minimum mean square error (LMMSE) channel estimator to increase spectrum efficiency in orthogonal frequency division multiplexing (OFDM) transmit diversity. The pilot symbols for OFDM transmit (Alamouti) diversity are exclusively allocated in two OFDM symbols in different antennas, which causes serious degradation of spectrum efficiency. To reduce the number of pilot symbols, our subcarrier allocation method uses repetition-coded data symbols, and the proposed channel estimator maintains good bit error rate (BER) performance.
    TIIS. 01/2008; 2:209-221.
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, an enhanced time-domain cancellation method is proposed for inter-carrier interference (ICI) reduction in OFDM systems. The conventional time-domain cancellation does not work well in deep fades. In order to supplement the conventional method, the simple repetition (de-)coding and the modulation order increasing are employed in the time-domain cancellation. The approximated repetition decoding provides reliable symbols in the regeneration operation, and the increased modulation order maintains the spectral efficiency. Simulation results indicate that the proposed method using 16QAM significantly improves the BER performance compared to the conventional method using QPSK, while maintains the spectral efficiency. Moreover, the proposed method using 64QAM concurrently improves both the BER performance and the spectral efficiency.
    Vehicular Technology Conference, 2007. VTC2007-Spring. IEEE 65th; 05/2007
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we investigate the conventional windowed DFT-based channel estimation for OFDM systems with guard bands. The conventional method suffers from the edge effect and the pilot position mismatch. In order to solve the problems, we propose an enhanced DFT-based channel estimation using virtual interpolation with guard bands prediction, where linear minimum mean square error (LMMSE) smoothing/prediction and circular frequency shifting are employed. This technique can efficiently mitigate the edge effect caused by the DFT of the truncated channel impulse response and compensate the pilot position mismatch that pilot symbols are not allocated at the first and the last subcarriers in a useful band. Simulation results show that the proposed method has about 5 dB SNR gain at BER=10<sup>-3</sup> compared to the conventional method and is as good as the frequency-domain LMMSE method
    Personal, Indoor and Mobile Radio Communications, 2006 IEEE 17th International Symposium on; 10/2006
  • Won-Gi Jeon, Hyeok-Koo Jung
    [Show abstract] [Hide abstract]
    ABSTRACT: In this letter, a hybrid selection combining (SC) and maximal ratio receive combining (MRRC) technique is proposed for orthogonal frequency-division multiplexing (OFDM) systems with multiple receive antennas. The proposed technique still uses multiple receive antennas, but it has just a single RF front-end and a single baseband demodulator. In comparison with the OFDM system with no diversity, we can achieve superior gain irrespective of bandwidth efficiency, and also in comparison with the MRRC OFDM, we can achieve better gain under the bandwidth efficiency of 3 bps/Hz at the bit error rate of 10−6.
    01/2006;
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, an enhanced time-domain cancellation method is proposed for inter-carrier interference (ICI) reduction in OFDM systems. The conventional time-domain cancellation neglects the effect of channel variation in cyclic prefix during the time-domain cancellation and does not work well in deep fades. In order to supplement the conventional method, the simple repetition (de-)coding and the modulation order increasing are employed in the time-domain cancellation. The repetition coding provides reliable symbols in the regeneration operation, and the modulation order increasing maintains or increases the spectral efficiency. Simulation results indicate that the proposed method using 16QAM significantly improves the BER performance compared to the conventional method using QPSK, while maintains the spectral efficiency. Moreover, the proposed method using 64QAM concurrently improves both the BER performance and the spectral efficiency.
    Advances in Hybrid Information Technology, First International Conference, ICHIT 2006, Jeju Island, Korea, November 9-11, 2006, Revised Selected Papers; 01/2006
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes the analysis for implementation of a radio frequency (RF) receiver for low-rate wireless personal area networks (LR-WPANs), namely IEEE 802.15.4, for coexistence with various wireless devices in 2.4GHz ISM-band. With IEEE 802.15.4 standard spec-ification, it provides analysis of receiver performance requirements containing the system noise figure (NF), system third-order intercept point (IIP3), local oscillator phase noise and selectivity. With some assumption, it illustrates relation-ship between minimum detectable signal (MDS) and various situations considering for the effects of noise generated from other wireless devices according to communication distance. Here, we can infer the necessity of much tighter specification requirements than standard’s that for various communication field environments.
    Communications, 2005 Asia-Pacific Conference on; 11/2005
  • [Show abstract] [Hide abstract]
    ABSTRACT: This letter derives and computes the detection probability of timing synchronization in a wireless personal area network (WPAN) system encountered with a multipath Rayleigh fading channel. The timing synchronization scheme using CAZAC training symbols and correlation techniques is adopted. For measuring system performance, the sync detection probability derived in the considered system is evaluated in a multipath Rayleigh fading channel.
    IEEE Communications Letters 04/2005; · 1.46 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An orthogonal frequency-division multiplexing (OFDM)-code-division multiple-access (CDMA) system employing various diversity schemes is considered as a possible candidate for broadband wireless access network applications. With an emphasis on a preamble design for multichannel separation, we address a channel estimation based on the time-domain windowing and its imperfectness in the space-time block-coded (STBC) OFDM-CDMA systems, respectively. Also, for a simple construction of the OFDM-CDMA system with the low peak-to-average power ratio (PAR) and reduced transmitter complexity, we investigate a simple PAR reduction scheme and its combination with both decimated selective mapping (SLM) and partial transmit sequence (PTS) methods. Taking into account the false side information introduced by the PAR reduction scheme, the effects of diversity techniques and PAR on the performance of the STBC OFDM-CDMA system are investigated and the maximum achievable diversity gain for a two-path Rayleigh-fading environment is evaluated. From the presented results, we find that the OFDM-CDMA signal with the low PAR is easily constructed by a simple phase transform and its combination version with the SLM and PTS approaches can be implemented to be less complex by decimating the OFDM samples. At the same time, the OFDM-CDMA system applying a space-time-frequency diversity with two and four transmit antennas can give the diversity of D=4 and D=8 for the multiuser case with half user capacity, respectively, even if encountered with the false side information.
    IEEE Transactions on Vehicular Technology 02/2005; · 2.64 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A time-varying multipath channel causes co-channel interference (CCI) as well as inter-carrier interference (ICI) in a space-time block coded orthogonal frequency-division multiplexing (STBC-OFDM) system using two transmit antennas and an conventional simplified decoding scheme (SDS). In this paper, we derive the power of the CCI as a function of normalized channel variation rate. Also, we propose a successive interference cancellation (SIC) technique to improve the performance of the STBC-OFDM by considering the CCI mechanism. The proposed SIC technique can compensate the CCI to some extend with slightly increased complexity compared to the SDS.
    Vehicular Technology Conference, 2005. VTC 2005-Spring. 2005 IEEE 61st; 01/2005
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper proposes an improved discrete Fourier transform-based and pilot-symbol-aided channel estimation (DFT-based PSA CE) for coherent orthogonal frequency division multiplexing (OFDM) systems. Conventional DFT-based PSA CE suffers from the dispersive distortion of an estimated channel impulse response (CIR) caused by virtual carriers. The proposed method estimates an equal-spaced channel frequency response (CFR) in a virtual carrier region by using forward and backward linear prediction (FBLP). Simulation results show that the proposed method outperforms the conventional one with slightly increased complexity and provides a performance similar to the frequency domain linear minimum mean square error (LMMSE) channel estimation with significantly reduced complexity.
    Vehicular Technology Conference, 2005. VTC 2005-Spring. 2005 IEEE 61st; 01/2005
  • IEICE Transactions. 01/2005; 88-B:781-783.
  • IEEE Communications Letters. 01/2005; 9:255-257.
  • [Show abstract] [Hide abstract]
    ABSTRACT: This letter investigates the performance degradation due to the imperfect parameters in orthogonal frequency- and code-division multiplexing (OFCDM) systems with multiple antennas. For the performance evaluation, the average bit error rate (BER) expression is generalized to the multiple-antenna case in the presence of the channel estimation error and frequency offset. Derived results show that the multiple-antenna OFCDM systems experience a severe BER degradation regardless of the number of users.
    IEEE Communications Letters 02/2004; · 1.46 Impact Factor

Publication Stats

171 Citations
20.11 Total Impact Points

Institutions

  • 2009
    • Chung-Ang University
      • School of Electrical and Electronics Engineering
      Seoul, Seoul, South Korea
  • 2008
    • Korea Electronics Technology Institute
      Sŏngnam, Gyeonggi Province, South Korea
  • 2003–2005
    • Sejong University
      • Department of Information and Communication Engineering
      Sŏul, Seoul, South Korea