• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.895-901
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• 2016

The next generation wireless and satellite communications require high transmission efficiency and high reliability to provide various services with subscribers. To satisfied these requirements, incorporated MIMO (Multiple Input Multiple Output) system with FTN (Faster Than Nyquist) techniques based on layered space time coded method are considered in the paper. To improve performance, STTC (Space Time Trellis Code) was employed as an inner code. As the same as SISO (Single Input Single Output) system, the outer codes are turbo codes. In receiver side, BCJR algorithm is used for STTC decoding in order to eliminate interferences induced by FTN transmission. They can yield significantly increased the data rates and improved link reliability without additional bandwidth. Therefore, we proposed a new decoding model for MIMO FTN model and confirmed that performance was improved compared to conventional SISO model according to amount of interference for FTN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4A
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• pp.296-303
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• 2005

In this paper, we evaluate system performance and propose signal separation and detection when a user with one antenna shares the co-channel together with a user with two space-time coded antennas. The proposed technique can identify co-channel users by an interference cancellation method and detect the signals by maximum likelihood method. Simulation results show that the shortcoming of the Minimum Mean-Squared Error technique which can be applied two users with the same number of antenna but can not applied for heterogeneous MIMO users with the different number of antennas. Also, we apply the proposed scheme to OFDM system and evaluate the system performance. By simulations, we identify that the performance of the proposed system is the same as that of the existing single antenna users and improves the performance of the two-antenna MIMO users.

• Journal of Internet Computing and Services
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• v.8 no.4
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• pp.61-70
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• 2007

In this paper, we propose and observe the Adaptive Modulation system with optimal Turbo Coded V-BLAST(Vertical-Bell-lab Layered Space-Time) technique that is applied the extrinsic information from MAP Decoder in decoding Algorithm of V-BLAST: ordering and slicing. And comparing the proposed system with the Adaptive Modulation system using conventional Turbo Coded V-BLAST technique that is simply combined V-BLAST with Turbo Coding scheme, we observe how much throughput performance and SNR has been improved. In addition, we show that the proposed system using STD(Selection Transmit Diversity) scheme results in on improved result, By using simulation and comparing to conventional Turbo Coded V-BLAST technique with the Adaptive Modulation systems, the optimal Turbo Coded V-BLAST technique with the Adaptive Modulation systems has SNR gain over all SNR range and better throughput gain that is about 350Kbps in 11dB SNR range. Also, comparing with the conventional Turbo Coded V-BLAST technique using 2 transmit and 2 receive antennas, the proposed system with STD scheme show that the improvement of maximum throughput is about 1.77Mbps in the same SNR range and the SNR gain is about 5.88dB to satisfy 4Mbps throughput performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.164-167
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• 2005

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 propose 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.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.4
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• pp.64-69
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• 2009

Bit-interleaved coded modulation(BICM) applied to Alamouti's orthogonal space-time block code(OSIBC) has a rate loss problem In this paper, we expand orthogonal space-time block code(OSTBC) and apply bit-interleaved coded modulation (BICM) to expanded OSTBC(XOSIBC) to obtain a diversity gain without a rate loss. Binary phase shift keying(BPSK) design example is presented. Simulation results are also provided.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.10
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• pp.31-40
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• 2013

In this paper, the spatial modulation (SM) multi-input multi-output (MIMO) system is proposed for indoor wireless local area networks (WLANs) with improved spectral efficiency. SM is suitable for high speed WLANs with avoiding the inter channel interference (ICI). Only one transmit antenna is activated in SM at each symbol interval. Therefore, it fails to attain the maximum coding gain of MIMO. The space time block code (STBC)-SM MIMO system can attain the maximum diversity gain at the expense of spectral efficiency. The proposed Golden-SM MIMO system uses the Golden code to improve the coding gain and spectral efficiency at the same time. The Golden code is adapted for STBC-SM and it makes the new code book for transmission symbols. The performance of the proposed system is compared with the conventional systems with computer simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10C
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• pp.923-929
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• 2003

Turbo processing have been known as methods close to Shannon limit in the aspect of wireless multi-input multi-output (MIMO) communications similarly to wireless single antenna communication. The iterative processing can maximize the mutual effect of coding and interference cancellation, but LDPC coding has not been used for turbo processing because of the inherent decoding process delay. This paper suggests a LDPC coded MIMO system with turbo parallel space-time (Turbo-PAST) processing for high-speed wireless communications and proposes a average soft-output syndrome (ASS) check scheme at low signal to noise ratio (SNR) for the Turbo-PAST system to decide the reliability of decoded frame. Simulation results show that the suggested system outperforms conventional system and the proposed ASS scheme effectively reduces the amount of turbo processing iterations without performance degradation from the point of average number of iterations.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.64-66
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• 2010

In this paper, we propose a temporal diversity scheme based on the vector perturbation for a multiuser multipleinput multiple-output (MIMO) broadcasting system. Our method is inspired by the fact that precoding process of the vector perturbation designed to suppress the multiuser interference causes a reduction of the transmitted signal power. In order to boost up the transmit power, we employ a non-integer based vector perturbation together with temporal transmit diversity. We show from the simulation on 10${\times}$10 multiuser MIMO system that the proposed method outperforms the epetition coded vector perturbation scheme as well as the standard vector perturbation.

• Journal of information and communication convergence engineering
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• v.2 no.2
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• pp.61-66
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• 2004

This paper presents a way to maximize transmission efficiency and reception ability through transmission diversity technology, which can be adapted to wireless multimedia Wireless LAN system. The presented method is a comparative analysis between a case where parameter a for time average is 0.3.1 with consideration of channel presumption with two types of rms delayed spread, which is 50nsec. 150nsec, for the performance analysis of STTC (Space-Time Trellis Code) adopting time-space ciphering method appropriate for MIMO channel, and performance in the case where presumed channel value from long training column section is applied to according frame in a single frame. The result showed that BER brought SNR improvement of l.0dB in $10^{-3}$ when a was 0.3 than adopting only the long training column, and showed increase of general performance improvement for the sake of time average rather than the case without.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2493-2508
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• 2012

The performance of a MIMO system with adaptive modulation (AM) and space-time coding over Ricean fading channels for perfect and imperfect channel state information (CSI) is presented. The fading gain value is partitioned into a number of regions by which the modulation is adapted according to the region the fading gain falls in. Under a target bit error rate (BER) constraint, the switching thresholds for AM are given. Based on these results, we derive the calculation formulae of the theoretical spectrum efficiency (SE) and average BER. As a result, closed-form SE expression and accurate BER expression are respectively obtained. Besides, using the approximation of complementary error function, a tightly closed-form approximation of average BER is also derived to simplify the calculation of accurate theoretical BER. Computer simulation shows that the theoretical SE and BER are in good agreement with the corresponding simulation, and the approximate BER is also close to the accurate one. The results show that the AM scheme in Ricean fading channel provides better SE than that in Rayleigh fading channel due to the direct-path propagation, and has performance degradation in SE and BER for imperfect CSI.