• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1777-1786
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• 1996

This paper describes theories and implementation techniques of a digital high-definition television(HDTV) modem based on 32-QAM for terrestrial broadcasting. We proposed a digital demodulation scheme and a symbol timing recovery structure based on the band edge component maximization(BECM) method. The adaptive equalizer has 256 complex taps to remove the multipath of delays ranging from -2.mu.s~+24.mu.s with a new T/2-spaced blind equalization algorithm. computer simulation results reveal that the proposed algorithm outperforms other conventional blind equalization algorithm a digital HDTV modem with 4.91MHz symobol rate is implemented by utilizing the proposed algorithms. All processings for modem operations such as demodulation, estimation of symbol timing phase error, adaptive equalization, and carrier recovery except IF signal processing and sampling phase control part of the AD converter are done in digital domain. Especially, the carrier recovery loop can track a carrier offset of upto .+-.350KHz.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.127-133
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• 2012

In this paper, the concerned CMA (Constant Modulus Algorithm) adaptive equalizer convergence rate and residual inter-symbol interference using cost function in order to improved to the ACMA (Advanced CMA). The CMA method compensates amplitude but does not compensate phase. On the other hand, The RCA (Reduced Constellation Algorithm) method compensates both the amplitude and the phase but it has the convergence rate problem. MCMA method is a way to solve the phase problem of CMA method compensates both the amplitude and the phase after respectively calculating the real and imaginary components. But it is more than poor CMA method in the complexity of hardware and the compensation performance. The cost function can advantages by improving the CMA and a MCMA (Modified CMA) equalizer so that the amplitude and phase retrieval the equalization steady-state to reduce the error by using ISI and faster convergence rate and performance is good SER (Symbol Error Ratio) was confirmed by computer simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.10
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• pp.1147-1154
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• 2016

A faster-than-Nyquist (FTN) transmission scheme has been attracting great attention as a spectral efficient transmission scheme. In the FTN transmission scheme, modulated symbols are transmitted at a rate higher than Nyquist rate and thus, a performance loss due to the inter-symbol interference (ISI) is unavoidable. To minimize the performance loss in the FTN transmission scheme, parameters should be carefully optimized. Unfortunately, simulation-based parameter optimization requires significant amount of time and computing power, especially for 2-dimensional FTN systems. In this paper, we propose a 2-dimensional FTN transmission scheme using the optimized parameters based on numerical analysis and simulation results on the ISI. Compared with the conventional Nyquist system, the proposed 2-dimensional FTN transmission scheme not only offers virtually identical bit error performance but also offers higher spectral efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4A
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• pp.386-393
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• 2010

In this paper, we analyse HARQ scheme that utilizes symbol mapping diversity (SMD) techniques such as MDSM and CORE. The exploitation feasibility of MDSM and CORE is evaluated in the perspective of system complexity and storage capacity as we consider a BICM system based on 3GPP LTE standards and multipath fading channels. Also, a simple method which obtains SMD effects by circularly shifting bit-block in a codeword is proposed. The experimental results performed in BICM-OFDM systems with single antenna as well as multiple antennas show that frame error rate of the proposed method is close to that of CORE while having lower complexity.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.3
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• pp.223-229
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• 2004

Recently, OFDM and STC techniques have been considered to be candidate to support multimedia services in the next generation mobile radio communications and have been developed the many communications systems in order to achieve the high data rates. In this paper, we propose the Trellis-Coded Differential Space Time Modulation-OFDM system with multiple symbol detection. The Trellis-code performs the set partition with unitary group codes. The Viterbi decoder containing new branch metrics is introduced in order to improve the bit error rate (BER) in the differential detection of the unitary differential space time modulation. Also, we describe the Viterbi algorithm in order to use this branch metrics. Our study shows that such a Viterbl decoder improves BER performance without sacrificing bandwidth and power efficiency.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.281-284
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• 2002

Error resilience for image coding is an important component of multimedia communication system. Error resilience schemes address loss recovery from the compression perspective. Multiple description coding (MDC) is one of the error resilience techniques promising for robust video transmission. It is the way to achieve tradeoff description such as scalar quantization, correlating transform and the quantized frame expansion. In this paper, we consider Multiple Description Scalar Quantization (MDSQ) to wavelet domain. Conventional MDSQ schemes considered description with equal weights in each sub-bands. But, we can see that the each sub-bands is unequal contribution to whole image quality. Therefore, we experiment the multiple design MDSQ table to make probability of zero index high, which gives high efficiency in arithmetic symbol coder. We also compare our proposed method with the conventional methods and show improved performance in terms of redundancy-rate-distortion.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.3
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• pp.304-306
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• 2016

In this letter, we investigate the performance of coherent free-space optical(FSO) systems under pulsed noise jamming conditions. In particular, we derive the average bit error probability of the coherent FSO systems with the pulsed noise jamming in a closed-form. Also, we derive the optimal fraction of symbol time of the jammer. We confirm the derived average error probability expressions by the exactly matching Monte-Carlo simulation results.

• ETRI Journal
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• v.38 no.4
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• pp.606-611
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• 2016

This paper presents antenna selection schemes for recently proposed quadrature spatial modulation (QSM) systems. The antenna selection strategy is based on Euclidean distance optimized antenna selection (EDAS). The symbol error rate (SER) performance of these schemes is compared with that of the corresponding algorithm associated with spatial modulation (SM) systems. It is shown through simulations that QSM systems using EDAS offer significant improvement in terms of SER performance over SM systems with EDAS. Their SER performance gains are seen to be about 2 dB-4 dB in $E_s/N_0$ values.

• Proceedings of the Korea Contents Association Conference
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• 2004.11a
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• pp.384-388
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• 2004

In this paper, we analyses transmission performance of synchronization pattern for over the air rekeying in aerial tactical link of LINK16, when it is given by symbol error rate, in respect of pattern detection probability and false alarm probability.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.213-214
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• 2008

In this paper, we analyze the performance of a cooperative communication wireless network over independent and identically distributed (IID) Nakagami-m fading channels. A simple transmission scheme is considered where the relay is operating in amplify-forward (AF) mode. A closed-form expression for symbol error rate (SER) is obtained using the moment generating function (MGF) of the total signal to noise ratio (SNR) of the transmitted signal with binary phase shift keying (BPSK).