• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.39-44
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• 2012

In this paper, we studied a high speed Trellis Coded Modulation (TCM) system and 8PSK-TCM system, and compare 8PSK-TCM system with QPSK system of BER. We know that 8PSK-TCM had 3 db improvement of BER than QPSK. And we demonstrated the superiority of 8PSK-TCM by simulating with Matlab. Input signal was 2 bits long, and 8PSK-TCM used 3bits long. Results of this simulation said that 8PSK-TCM had 3 db improvement of BER than QPSK.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.11
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• pp.837-842
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• 2017

In this paper, as a basic study for combination of turbo equalizer and 4D-8PSK-TCM(4 Dimensional 8 Phase Shift Keying Trellis Coded Modulation) system, which is recommended for X-band band satellite communication in CCSDS, a system combining 8PSK-TCM system and turbo equalizer has designed and performance evaluation of the system has performed. BER performance of 8PSK and 8PSK-TCM systems has evaluated and analyzed in AWGN, Proakis B and Proakis C channels in detail. As results of simulation, BER performance of 8PSK-TCM system is better than 8PSK system in AWGN environment. Furthermore, it can be confirmed that the system combining the 8PSK-TCM system with the turbo equalizer can further improve the BER performance through iterative equalization in the ISI channel environment. The 8PSK-TCM system combined with the turbo equalizer requires SNR of 5.9 dB for BER performance of $10^{-3}$ with 5 iterative equalization in Proakis B and SNR of 9.1 dB for BER of $10^{-2}$ with 5 iterative equalization in Proakis C.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.17 no.10
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• pp.1147-1156
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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 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 different is introduced in order to improve the bit error rate(BER) performance in differential detection of the trellis-coded $\pi/8$ shift 8PSK. The proposed Viterbi decoder is conceptually the same as the sliding multiple detection 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) 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 nest proposed algorithm can be used in the TC $\pi/8$ shift 8PSK as well as TCMDPSK.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.5B
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• pp.797-808
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• 2000

This paper presents the bit error rate(BER) upper bounds for trellis coded asymmetric 8PSK(TC-A8PSK) system using the Ka-band satellite in the rain fading environment. The probability density function(PDF) for the rain fading random variable can be theoretically derived by assuming that the rain attenuation can be approximated to a long-normal distribution and the rain fading parameters are calculated by using the rain precipitation data from the Crane global model. Furthermore, we analyze the BER upper bounds of TC-A8PSK system according to the number of states in the trellis diagram and the availability of channel state information(CSI). In the past, Divsalar and Simon[9] has analyzed the BER upper bounds of 2-state TCM system in Rician fading channels however this paper is the first to analyze the BER upper bounds of TCM system in the rain fading channels. Finally, we summarize the dominant six factors which are closely related to the BER upper bounds of TC-A8PSK satellite system in the rain fading channel as follows: 1) frequency band, 2) rain intensity, 3) elevation angle, 4) signal to noise ratio, 5) asymmetric angle, and 6) availability of CSI.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.4
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• pp.535-543
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• 2002

In this paper, we propose $\pi$/8 shift 8PSK and trellis-coded $\pi$/8 shift 8PSK-OFDM techniques by applying $\pi$/4 shift QPSK to trellis-coded modulation (TCM), and performing signal set expansion and set partition correspondingly based on phase difference. In our Viterbi decoding algorithm, up to L phase differences from successively received symbols are employed in the new branch metrics. Such sliding multiple symbol detection (SMSD) method provides improved bit-error-rate (BER) performance in the differential detection of the trellis-coded $\pi$/8 shift 8PSK-OFDM signals. The performance improvements are achieved for different communication channels without sacrificing bandwidth and power efficiency. It thus makes the proposed modulation and sliding detection scheme more attractive for power and band-limited systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.399-401
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• 2013

In this paper, we present the method to impove the performance by using iterative decoding in LDPC codes with 8-PSK modulation. Iterative decoding is the technique that improve the performance after the input signals of receiver are re-calculated by using the soft decision output of decoder. DVB-S2 system with 8-PSK modulation based on iterative decoding had a better performance than DVB-S2 with 8-PSK modulation over Gaussian channels.

• The Journal of Korean Institute of Information Technology
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• v.17 no.3
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• pp.31-41
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• 2019

In this paper, we design and implement the simulator for the transmitter and receiver of 4D-8PSK TCM with 2.0, 2.25, 2.5, and 2.75 bits/symbol-channel transmission efficiency recommended by the CCSDS for satellite communications, and then analyze the BER performance of 4D-8PSK TCM system in AWGN channel. The transmitter of 4D-8PSK TCM is designed in accordance with the recommendation in the CCSDS standard. Meanwhile, for the receiver design of 4D-8PSK TCM, we design the differential decoder generalizing the differential encoder/decoder scheme. The trellis decoding algorithm is designed by applying the auxiliary trellis information and the Viterbi algorithm, and an 8-dimensional constellation mapper equation given in the CCSDS standard is deconstructed to design constellation mapper. Especially, we present the optimized receiver for 4D-8PSK TCM system by investigating the BER performances for the traceback lengths in the Viterbi decoder through computer simulations..

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.3
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• pp.301-309
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• 1993

The performance of trellis coded 8-PSK systems over m-distributed fading channel is analyzed. To compensate the performance degradation due to the fading in mobile communication channels, the trellis code which can obtain the coding gain without bandwidth expansion is used. Using the Chernoff bound and generating function techniques for the trellis coded 8-PSK systems with 4-state and 8-state, the upper bound of the bit error probability is derived. The trellis code of 8-state is better than that of 4-state in the capability of error correction. The coded performance is much better under severe fading environment.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8A
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• pp.1133-1140
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• 1999

In order to provide high-speed wide-band multimedia services via Low earth(LEO) mobile satellire, power and bandwidth efficient digital transmission technique should to employed. This paper analyzes the performance of Trellis-soded 16QAM and 8PSK-2AM which can transmit twice as much inforemation as QPSK in nonlinearly amplified LEO mobile satellite channel. In the analysis the nonlinear mobile satellite channel is modelled by Rician fading channel amplified by Fujitsu's GaAs FET HPA. Our simulation result shows that 8PSK-2AM is less sensitive to the satellite channel nonlinear distortion and its BER performance is better than that of 16QAM. The BER performance of 8PSK-2AM is further improved by optimizing its signal constellation. Accocordingly it is found that Trellis-coded 8PSK-2AM could provide multimedia services such as Satellite Internet, DBS, DAB and ISDB more efficiently in the power and bandwidth limited mobile satellite channel.