• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1869-1876
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• 2006

Recently, 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 Nose the Trellis-Coded Differential Space Time Modulation 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 Viterbi decoder improves BER performance without sacrificing bandwidth and power efficiency.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.117-125
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• 2004

Space-time coding and modulation exploit the presence of multiple transmit antennas to improve performance on multipath Rayleigh fading channels. In this paper, we propose the Trellis-Coded Differential Space Time Modulation-OFDM system with multiple symbol detection. The Trellis-code perform 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 Viterbi decoder improves BER performance without sacrificing bandwidth and power efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1546-1553
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• 1996

The bit error probability of RS/trellis concatenated coded-modualtion system in the mobile radio channel is analyzed. A new upper bound to the symbol error probability of the inner TCM in the mobile radio channel is obtained by exploiting the unequal symbol error probability of the TCM. This bound is applied to the derivation of the upper bound to the bit error probability of the concatenated coded-modulation system. An efficient way of searching distance spectrum of the TCM in mobile radio channel is devised. Our new bounds are tighter than the earlier studied other bounds.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.140-145
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• 2017

A channel is very sever in an underwater acoustic communication. Therefore, a modulation method with high spectrum efficiency is needed in an underwater acoustic communication. PSK(phase shift keying) for transmitting 1 bit or 2 bits is robust to noise, but sensitive to noise about more than 3 bits. CPFSK error performance for transmitting 1 bit or 2 bits is similar to that of PSK and CPFSK decreases high frequency components in modulation signal. In the paper, I analyze the performance of trellis coded 4-CPFSK modulation.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.2
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• pp.105-114
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• 2000

In this paper, we propose a bandwidth-efficient channel coding scheme using the turbo trellis-coded modulation with multiple symbol detection. The turbo code can achieve good bit error rates (BER) at low SNR. That comprises two binary component codes and an interleaver. TCM codes combine modulation and coding by optimizing the euclidean distance between codewords. This can be decoded with the Viterbi or the symbol-by- symbol MAP algorithm. But we present the MAP algorithm with branch metrics of the Euclidean distance of the first phase difference as well as the Lth phase difference. The study shows that the turbo trellis-coded modulation with multiple symbol detection can improve the BER performance at the same SNR.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.121-124
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• 2001

In this paper, we propose a robust trellis coded OFDM(orthogonal frequency division multiplexing) system for wireless communications over frequency selective fading channels. Computer simulations show that the proposed system achieves the better frame error rate(FER) performance as compared with the conventional Space time coded OFDM system in the correlated channel with multiple transmitter antennas.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.3 no.2
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• pp.30-38
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• 1992

In this paper, in order to apply the $\pi$/4 shift QPSK to TCM, we propose the $\pi$/8 shift 8PSK modulation technique and the trellis-coded $\pi$/8 shift 8PSK performing signal set expansion and set partition by phase difference. In addition, the Viterbi decoder with branch metrics of the squared Euclidean distance of the first phase difference as well as the Lth phase difference is introduced in order to improve the bit error rate(BER) performance in differential detection of the trellis-coded $\pi$/8 shift 8 PSK. The proposed Viterbi decoder is conceptually the same as the sliding multiple de- tection by using the branch metric with first and Lth order phase difference. We investigate the performance of the uncoded .pi. /4 shift QPSK and the trellis-coded $\pi$/8 shift 8PSK with or without the Lth phase difference metric in an additive white Gaussian noise (AWGN) and Rayleigh fading channel using the Monte Carlo simulation. The study shows that the $\pi$/4 shift QPSK with the Trellis-code i. e. the trellis-coded $\pi$/8 shift 8PSK is an attractive scheme for power and bandlimited systems and especially, the Viterbi decoder with first and Lth phase difference metrics improves BER performance. Also, the next proposed algorithm can be used in the TC $\pi$/8 shift 8PSK as well as TC MDPSK.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1743-1751
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• 1989

In this paper, we consider trellis-coding techniques with the convolutional encoder R=k/(k+1) for improving the reliability of digital transimission over bandlimited noisy PRS and 49-QPRS channels. Employing the R=k/(k+1) convolutional code for the PRS channel results in over 3 dB of coding gain comparing with the baseline system. The trellis-coded 49-QPRS system can be realized by combining the 9-QPRS system with the R=1/2 convolutiona code, which can be improved by over 2dB coding gain comparing with the 9-QPRS system. In additin, we study a method of avoiding the occurance of unlimited runs of identical output to prevent operation of timing error.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.12
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• pp.1401-1412
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• 1992

On band limited channel like satellite communication and voice communication. TCM(Trellis Coded Modulation) is a communication method that has coding gain which combines modulation with channel coding without bandwidth expansion. In this paper, we apply PAM, PSK, QAM to TCM, and propose the extended path back method decoding algorithm which improved drawback of viterbi decoding algorithm and apply to TCM this decoding algorithm. Using Monte Carlo simulation, we analyze performance of each modulation technique and efficiency of decoding algorithm.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.2071-2074
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• 2002

This paper introduces an encoder design method of Turbo TCM (Trellis Coded Modulation) with symbol puncturing. TTCM consists of two simple trellis codes in parallel and modulator. To obtain an good encoder, we calculate the free distance by the assumption that the punctured symbol is transmitted from the subset that consist of signals with the same systematic bit at random. We develop a search program to find the component encoder which maximize the free distance. Especially, for 8-PSK with code rate 2/3, we search for the component codes. We find a new encoder which has better BER performance than that of Robertson′s encoder. We verify the results through the simulation."