• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.3
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• pp.405-409
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• 2002

Recently, the FCC commissioners approved limited uses of UWB, and have promised to review the standards to explore the potential of more flexible standards and to address the operation of additional types of UWB operations and technology. In this paper we study performances of UWB communication system according to M-ary schemes with BCH code. And under the AWGN channel, we analysis and compare error probability, the number of M-ary schemes to the two methods that pulse position modulation and pulse amplitude modulation.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.305-308
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• 2000

A technique to suppress the low frequency ripple voltage of the DC output in three phase buck diode rectifiers is presented in this paper. The proposed pulse frequency modulation methods and duty ratio modulation methods are employed to regulate the output voltage of the buck diode rectifiers and guarantee zero-current -switching(ZCS) of the switch over the wide load range The proposed control methods used in this paper provide generally good performance such as low THD of the input line current and unity power factor. IN addition control methods can be effectively used to suppress the low frequency ripple voltage appeared in the dc output voltage. The harmonic injection technique illustrates its validity and effectiveness through the simulations.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.4
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• pp.286-292
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• 2004

This paper presents a polyphase filtered orthogonal frequency division multiplexing (PF-OFDM) technique. The proposed structure uses a modified discrete Fourier transform (MDFT) transmultiplexer to achieve greater spectral efficiency than an OFDM system, while preserving backward compatibility with it. The prototype PF-OFDM filter has excellent time and frequency localization properties, which matte it possible to eliminate a guard interval (or cyclic prefix) and easily suppress interchannel interference (ICI). This modulation technique uses a single DFT structure, in contrast to a MDFT transmultiplexer, which requires two DFT polyphase filter banks. The PF-OFDM modulation is .justified over multipath Rayleigh fading channels.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.1
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• pp.48-55
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• 2017

This paper proposes a new link structure that transmits power, clock, and data through a single optical fiber for a future automotive network. A pulse-position modulation (PPM) technique is adopted to guarantee a DC-balanced signal for robust power transmission regardless of transmitted data pattern. Further, circuit implementations and theoretical analyses for the proposed PPM transceiver are described in this paper. A prototype transceiver fabricated in 65-nm CMOS technology, is used to verify the PPM signaling part of the proposed system. The prototype achieves a $10^{-13}$ bit-error rate and 0.188-UI high frequency jitter tolerance while consuming 14 mW at 800 Mb/s.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.4
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• pp.1954-1971
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• 2017

In this work, first, a multiuser detection (MUD) algorithm based on component-level soft interference cancellation and linear minimum mean square error (CLSIC-LMMSE) is proposed, which can enhance the bit error ratio (BER) performance of the traditional SIC-LMMSE-based MUD by mitigating error propagation. Second, for non-binary low density parity check (NB-LDPC) coded high-order modulation systems, when the proposed algorithm is integrated with partial mapping, the receiver with iterative detection and decoding (IDD) achieves not only better BER performance but also significantly computational complexity reduction over the traditional SIC-LMMSE-based IDD scheme. Extrinsic information transfer chart (EXIT) analysis and numerical simulations are both used to support the conclusions.

• Journal of Communications and Networks
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• v.16 no.3
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• pp.264-269
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• 2014

We consider transmission over body area networks. Due to the difficulty in assessing an accurate statistical model valid for multiple scenarios, we advocate a system design technique favoring robustness. Our approach, which is based on results in [12] and generalizes them, examines the variation of a performance metric when the nominal statistical distribution of fading is replaced by the worst distribution within a given Kullback-Leibler divergence from it. The sensitivity of the performance metric to the divergence from the nominal distribution can be used as an indication of the design robustness. This concept is applied by evaluating the error probability of binary uncoded modulation and the outage probability-the first parameter is useful to assess system performance with no error-control coding, while the second reflects the performance when a near-optimal code is used. The usefulness of channel coding can be assessed by comparing its robustness with that of uncoded transmission.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2529-2533
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• 1999

This paper proposes a modified hysteresis current control method based on space vector modulation. The proposed method differs from former works in that it uses effective voltage vectors instead of zero vectors while not significantly increasing the circuit complexity. The circuit uses outer band that is slightly wider than the usual current limit band (inner band) to detect the phase of current command and thereby the region information. The comparator output signals associated with the inner and outer band are used to determine the proper voltage vector that minimizes the current error and number of switching, with simple logic circuitry. The utilization of effective voltage vector is of particular importance when the ac-side emf is relatively large. Both the simulation and experiment show that the proposed method is more effective than the conventional one that uses zero vectors, in reducing the number of switching over a range of ac-side emf variation.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.475-477
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• 2005

We simulated 3rd order intermodulation distortion (IMD3) induced Carrier-to-Intermodulation Ratio (CIR) of laser diodes over a wide range of optical modulation index, and compared the results with commercial IMD3 induced CIR specification such as Composite Triple Beat (CTB) of DFB laser transmitter for CATV networks. It shows that the simulation results are in good agreement with the CATV CTB specification within 3dB margin. The results can be used to predict IMD3 induced CIR performance for various analog optical transmission systems with given optical modulation index and the number of transmission channels.

• ETRI Journal
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• v.25 no.4
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• pp.231-237
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• 2003

We derive and analyze the exact closed-form expression for the average bit error probability (BEP) of M-ary square quadrature amplitude modulation (QAM) for diversity reception in frequency-nonselective Nakagami fading. A maximal ratio combining (MRC) diversity technique with independent or correlated fading cases are considered. Numerical results demonstrate error performance improvement with the use of MRC diversity reception. The presented new expressions offer a convenient way to evaluate the performance of M-ary square QAM with an MRC diversity combiner for various cases of practical interest.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.4
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• pp.39-46
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• 1994

In this paper, the idea of using a multiple symbol obervation interval to improve error probability performance is applied to differential detection of MTCM(multiple trellis code modulation) with ${\Pi}$/4 shift QPSK, 8DPSK and 16DPSK. We propose two types of sliding multiple symbol differential detection algorithm, type 1 and type 2. The two types of sliding detection scheme are examined and compared with conventional(symbol-by-symbol) detection and bolck detection with these modulation formats in an additive white Gaussian noise(AWGN) using the Monte Carlo simulation. We show that the amount of improvement over conventional and block detection depends on the number of phases and the number of additional symbol intervals added to the observation. Computer simulagtion results are presented for 2,4,8 states in AWGN channel.