• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.826-829
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• 2007

In this paper, we proposed two systems, STTC scheme and STBC based on STTC scheme, to enhance the reliability of HDR-WPAN system and analyzed BER(bit error rate) performance of the proposed systems over the slow fading channel. The proposed systems obtained a diversity gain and coding gain without increasing an additional channel bandwidth. However, in terms of reliability, about 4dB improvement at $BER=10^{-3}$ was obtained by the STBC based on STTC scheme because of the additional diversity gain of STBC. From these results, STBC based on STTC scheme was more appropriate to improve the reliability and channel efficiency of HDR-WPAN system.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.9 no.2
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• pp.96-103
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• 2010

This paper studies the performance of STTC with minimum Hamming distance (MHD) mapping in order to improve the bit error rate (BER) performance. Unfortunately, the MHD mapping used in trellis coded modulation (TCM) or multiple trellis coded modulation (MTCM) cannot be directly applied to STTC because the trellis structure of STTC is generally different from that of TCM or MTCM. Therefore, we need a simple modification to apply the MHD mapping concept in STTC. The core of the modification assigns information bits with a Hamming distance in proportion to the sum of the Euclidean distance to trellis branch of STTC. To the best knowledge, this combination has not been considered yet. The BER performance is examined with simulations and the performance of MHD mapping is compared to that of well known natural mapping and Gray mapping on both fast Rayleigh as well as fast Rician fading channels. It is shown that the performance of MHD mapping is much better than that of natural mapping or Gray mapping over fast Rician fading channels, especially.

• Journal of information and communication convergence engineering
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• v.8 no.4
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• pp.387-392
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• 2010

This study focuses on improving MIMO-OFDM systems by combining a wireless communication architecture known as vertical BLAST(bell laboratories layered space-time) or V-BLAST and STTC(space time trellis coding). In this paper, the combination is done by introducing STTC in each V-BLAST layer. Moreover, this architecture uses multiple antennas that are grouped into small number of antennas which makes it less complex to decode by decoding every group. Whereas, in traditional V-BLAST, all the antennas form one group and they are decoded together at the receiver, therefore, this increases the complexity as the number of antennas is getting high. We compare the bit error rate performance of this system with MIMO-OFDM that uses convolutional coding instead of STTC. Under the same spectral efficiency, the simulation results prove that joining V-BLAST with STTC improves MIMO-OFDM systems performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.5C
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• pp.338-343
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• 2005

MIMO(Multiple Input Multiple Output) systems are considered as one of the most promising systems for next generation mobile communication systems which require efficient frequency resource utilization as well as high data rate transmissions. BLAST-STTC is the MIMO system which transmits information from many of STTC encoder groups with two transmit antennas and cancels the interference from other groups in receiver. In this paper we propose a reverse-ordered iterative decoding scheme for BLAST-STTC systems which achieve full diversity gain for all groups and improve the performance of interference cancellation, and compare the error performance of the proposed scheme with general schemes.

• Journal of Advanced Navigation Technology
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• v.12 no.1
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• pp.54-60
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• 2008

The reliability of conventional wireless communication systems are diminished by multi-path fading, shadowing, propagation delay, pathloss, AWGN and an interference of the symbols. Therefore, we need more reliable system which can stably transmit multimedia datas over the poor communication environments, so, in this paper, we used STBC system based on STTC that allows a maximum space diversity gain of STBC scheme and channel efficiency, coding gain and diversity gain of STTC scheme at the same time. We did then analyzed the performance over the correlated slow fading channel between transmitter and receiver channels.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.8 no.6
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• pp.141-148
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• 2009

Space-time block codes (STBC) have no coding gain but they provide a full diversity gain with relatively low encoder/decoder complexity. Therefore, STBC should be concatenated with an outer code which provides an additional coding gain. In this paper, we consider the concatenation of multiple trellis-coded modulation (MTCM) codes with STBC for achieving significant coding gain with full antenna diversity. Using criteria of equal transmit power, spectral efficiency and the number of trellis states, the performance of concatenated scheme is compared to that of previously known space-time trellis codes (STTC) in terms of frame error rate (FER). Simulation results show that MTCM codes concatenated with STBC offer better performance on fast Rayleigh fading channels, than previously known STTC with two transmit antennas and one receive antenna.

• Journal of Advanced Navigation Technology
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• v.6 no.2
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• pp.130-137
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• 2002

We present Space-Time Trellis Coded Code Division Multiple Access systems, which maintain the full diversity and coding gain of Space-Time Trellis Codes(STTC) and have the immunity to performance degradation caused by multipath fading. These STTC CDMA systems are constructed by adding the spreading and despreading processes of PN codes to STTC systems. In multipath fading channels, delay spreaded signals are detected and combined, then decoded. According to the combining and decoding methods, there are four decoding methods. There are optimum ML decoding without combining, adding multipath signals in each receive antenna before decoding, combining multi path signals in each antenna before decoding, and combining all received signals before decoding. Performance of these methods is proportional to complexity. Besides, all methods are shown to compensate the irreducible error rate which appears in multipath fading channels.

• Journal of Advanced Navigation Technology
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• v.11 no.3
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• pp.288-295
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• 2007

In this paper, we proposed two systems, STTC scheme and STBC-TCM scheme, to enhance the reliability of HDR-WPAN system and analyzed BER(bit error rate) performance of the proposed systems over the slow fading channel. The proposed systems had a diversity gain and coding gain without increasing an additional channel bandwidth. However, in terms of reliability, about 4dB improvement at BER=$10^{-4}$ was obtained by the STBC-TCM scheme. In addition, HDR-WPAN system with STBC-TCM scheme had a linear rise in system complexity of ML(maximum likelihood). From the results, STBC-TCM scheme was more appropriate to improve the reliability and channel efficiency and to reduce complexity of HDR-WPAN system.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.12
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• pp.20-26
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• 2012

The newly introduced model of a STTC-based Distributed Wireless Communication System (DWCS) can provide the capability of joint control of the signals at multiple cells. This paper has considered the virtual cell systems: the Dual Virtual Cell (DVC), and also proposes DVC employment strategy based on DWCS network. The considered system constructs DVC by using antenna selection method. Also, for multi-user high-rate data transmission, the proposed system introduces multiple antenna technology to get a spatial and temporal diversity gain and exploits space-time trellis codes known as STTC to increase a spectral efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.5
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• pp.504-511
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• 2016

In this paper, MIMO system based on turbo equalization techniques which LDPC codes were outer code and space time trellis codes (STTC) were employed as an inner code are studied. LDPC decoder and STTC decoder are connected through the interleaving and de-interleaving that updates each other's information repeatedly. In conventional turbo equalization of MIMO system, BCJR decoder which decodes STTC coded bits required two-bit wise decoding processing. Therefore duo-binary turbo codes are optimal for MIMO system combined with STTC codes. However a LDPC decoder requires bit unit processing, because LDPC codes can't be applied to these system. Therefore this paper proposed turbo equalization for MIMO system based on LDPC codes combined with STTC codes. By the simulation results, we confirmed performance of proposed turbo equalization model was improved about 0.6dB than that of conventional LDPC codes.