• Information and Communications Magazine
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• v.24 no.12
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• pp.14-21
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• 2007

This paper aims to improve the design of iterative detection and decoding(IDD) based on the soft interference cancellation with minimum mean squared error(SC-MMSE) detector, which shows low performance compared to the maximum a posteriori(MAP) detector. By means of extrinsic information transfer(EXIT) chart analysis, such low performance may be attributed to that the "pure"(original) turbo principle is not always best for IDD. Thus, we propose a new IDD architecture based on the SC-MMSE detector which uses new a priori information. Simulation results show that the performance of the proposed IDD is very close to that of IDD based on the MAP detector.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.8
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• pp.3589-3605
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• 2018

In this paper, we investigate an individual channel estimation problem for multiple-input multiple-output (MIMO) two-way amplify-and-forward (AF) relay networks. To avoid self-interference during the estimation of the individual MIMO channels, a novel blind interference cancellation (BIC) approach is proposed based on an orthogonal preceding framework, where a pair of orthogonal precoding matrices is utilized at the source nodes. By designing an optimal decoding scheme, we propose to decompose the bidirectional transmission into a pair of unidirectional transmissions. Unlike most existing approaches, we make the practical assumption that the nonreciprocal MIMO channel and the mutual interference of multiple antennas are both taken into consideration. Under the precoding framework, we employ an orthogonal superimposed training strategy to obtain the individual MIMO channels. However, the AF strategy causes the noise at the terminal to be the sum of the local noise and the relay-propagated noise. To remove the relay-propagated noise during the estimation of the second-hop channel, a partial noise-nulling method is designed. We also derive a closed-form expression for the total mean square error (MSE) of the MIMO channel from which we compute the optimal power allocation. The simulation results demonstrate that the analytical and simulated curves match fully.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.9
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• pp.739-743
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• 2013

In this paper, a two-dimensional (2-D) channel code for magnetic patterned media is proposed. Patterned media records an information bit on a magnetized dot. Since the space between adjacent tracks is narrow in order to increase the storage density, inter-track interference (ITI) and inter-symbol interference (ISI) can be problems. The amplitude of a bit signal can be corrupted by the 2-D ISI. The signal of the bit surrounded by the same value can be especially destructive, i.e. when its value is the same as the values of the eight surrounding bits. The proposed modulation coding scheme improves the decoding performance of patterned media by preventing this worst case and provides a better code rate than conventional channel codes.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.8
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• pp.7-14
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• 2011

In this paper we studied a conventional system and propose a new decoding scheme for Space-time Frequency Code with Interleaved System. We also addressed the quasi orthogonal function with Jacket matrices in modern 3GPP LTE uplinked advance system. We also introduce the Partial Interference Cancellation (PIC) group decoding which provides a framework to adjust the complexity-performance tradeoff by choosing the sizes of the information symbols groups.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.10
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• pp.856-867
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• 2018

This paper presents the applicability of MIMO joint decoding to dual-contact satellite systems in which two LEO satellites using X-band frequency band are transmitting each image data to two ground station antennas, simultaneously. When two satellites are closely positioned within the looking angle of the two antennas, each satellite interferes with each other by the relative antenna gain corresponding to an offset angle and this might cause the performance degradation without interference mitigation. To mitigate the performance degradation, SM MIMO techniques for joint decoding are applied. Especially, the relative antenna gain of ground station depending on the angle difference between two satellites in ground station antenna plays an important role in modelling the dual-contact satellite systems. The condition number of MIMO channel including the antenna gain calculated from the mathematical gain pattern model was primarily analyzed. Simulation results showed that the SM MIMO techniques using detection schemes such as ZF-SIC, MMSE-SIC, and ML can be applicable to dual-contact satellite systems.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.3
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• pp.13-18
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• 2011

Sphere Decoding (SD) is a decoding technique able to achieve the Maximum Likelihood (ML) performance in fading environments; nevertheless, the main disadvantage of this technique is its high complexity, especially in poor channel conditions. In this paper, we present an adaptive hybrid algorithm which reduces the conventional Sphere Decoder's complexity and keeps the ML performance. The system called Adaptive OSIC-SD modifies its operation based on Signal to Noise Ratio (SNR) information and achieves an optimal performance in terms of Bit Error Rate (BER) and complexity. Through simulations, we probe that the proposed system maintains almost the same bit error rate performance of the conventional SD, and exhibits a lower, quasi-constant complexity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.2
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• pp.275-280
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• 2016

In this paper, we propose a novel relay selection technique which utilizes a priori decoding information at relays for buffer-aided successive relaying networks. In the conventional relaying schemes, a single relay pair is selected for receiving data from the source and transmitting data to the destination. In the proposed technique, however, all relays except the relay selected for transmitting data to the destination try to decode the received signal from the source, and they store the data if they succeed decoding. The proposed technique selects the relay such that it can succeed its own transmission and it maximizes the number of relays successfully decoding the data from the source at the same time. It is shown that the proposed relaying technique significantly outperforms the conventional buffer-aided relaying schemes in terms of outage probability through extensive computer simulations.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.41-44
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• 2002

Alamouti proposes a two branch transmit diver-sity scheme that provides the same diversity order as maximal ratio combining at the receiver. It has many advantages of no bandwidth expansion, not requiring channel information at the transmitter and simple maximum likelihood decoding at the receiver. Papadias and Foschini extend this sch-eme to four transmit antennas and suggest several schemes to decrease the interference component and allow the attainment of the open-loop capacity. This paper shows the performance of ZF and MM-SE schemes comparing with ideal case on 4xl sy-stem over BER and 10% outage capacity.

• Proceedings of the IEEK Conference
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• 2000.11a
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• pp.137-140
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• 2000

In this paper. we analyzed the performance of a SFH (slow frequency hopping) system under partial-band jamming, multiple access interference and wide-band random noise. For the correction of burst errors due to channel hit, Reed-Solomon coding followed by block interleaving is employed. Errors-and-erasures decoding with side information is exploited to enhance the correctional capability. We derived a closed-form solution for the BER estimation. Errors resulting from random noise and erasures resulting from burst interference are separately analyzed and finally BER is computed due to these composite noise sources. Estimated BER performance is verified by computer simulation.

• International journal of advanced smart convergence
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• v.9 no.3
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• pp.141-144
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• 2020

Iterative decision feedback equalizer (IDFE) is a recursive equalization technique that can help to achieve an additional performance gain for the system by combining iterative channel decoding and interference cancellation. In a single carrier-based system, the intersymbol interference (ISI) is a critical problem that must be resolved since it causes frequency selective fading. Based on the idea of sharing the estimated information in the process of iteration, IDFE is considered as an efficient solution to improve the robustness of the system performance on the ISI channel. In this paper, the IDFE is applied on single carrier FDMA (SC-FDMA) system to evaluate the performance under ISI channel. The simulation results illustrate that IDFE helps to improve the performance of the SC-FDMA system, especially with long delay spread channels.