• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1323-1329
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• 2014

In this paper, we analyzed efficient decoding scheme with FTN (Faster than Nyquist) method that is transmission method faster than Nyquist theory and increase the throughput. we proposed viterbi equalizer model to minimize ISI (Inter-Symbol Interference) when FTN signal is transmitted. the proposed model utilized interference as branch information. In this paper, to decode FTN singal, we used turbo equalization algorithms that iteratively exchange probabilistic information between soft Viterbi equalizer (BCJR method) and LDPC decoder. By changing the trellis diagram in order to maximize Euclidean distance, we confirmed that performance was improved compared to conventional methods as increasing throughput of FTN signal.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6A
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• pp.568-576
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• 2011

In this paper, a channel assignment technique to mitigate interferences due to ISI(Inter Symbol Interference) and ICI(Inter Carrier Interference) caused by TDoA(Time Difference of Arrival) among distributed MRs(Mesh Routers) in OFDMA(Orthogonal Frequency Division Multiple Access)-based WMN(Wireless Mesh Network) is proposed. The SINR(Signal to Interference and Noise Ratio) associated with the channel assignment for each MR is defined to minimize the effect of ISI and ICI due to TDoA in WMN, which is then used to propose an channel assignment technique considering fairness constraint. It is verified by computer simulation that the proposed channel assignment technique can improve the performance of BER(Bit Error Rate) in WMNs with compared to the conventional technique.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.2
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• pp.100-106
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• 2007

In this paper, the performance of OFDM(Orthogonal Frequency Division Multiplexing) and FMT(Filtered Multi-tone) Systems is compared under jamming environment. Two systems are multi-carrier systems to improve data rates. Through the comparison of two systems under jamming environment, the characteristics and strong/weak points of each system are analyzed.

• Journal of information and communication convergence engineering
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• v.14 no.2
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• pp.78-83
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• 2016

In underwater acoustic communication, the transmitted signals are severely influenced by the reflections from both the sea surface and the sea bottom. As very large reflection signals from these boundaries cause an inter-symbol interference (ISI) effect, the communication quality worsens. A channel estimation-based equalizer is usually adopted to compensate for the reflected signals under the acoustic communication channel. In this study, a feed-forward equalizer (FFE) with the least mean squares (LMS) algorithm was applied to a quadrature phase-shift keying (QPSK) transmission system. Two different types of equalizers were adopted in the QPSK system, namely a real-coefficient equalizer and a complex-coefficient equalizer. The performance of the complex-coefficient equalizer was better than that of two real-coefficient equalizers. Therefore, a Hilbert transform was applied to the real-coefficient binary phase-shift keying (BPSK) system to obtain a complex-coefficient BPSK system. Consequently, we obtained better results than those of a real-coefficient equalizer.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.112-117
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• 2016

This paper presents a half-rate current-integrating DFE receiver with sub-unit interval (sub-UI) inter-symbol interference (ISI) cancellation. By having a single additional DFE tap in each data path, the proposed DFE receiver can minimize BER degradation due to input pattern dependency and feedback tap latency problems in conventional current-integrating DFE receivers. The proposed DFE receiver was designed and fabricated in a 45 nm CMOS process, whose measurement results indicated that the BER bathtub width is increased from 0.235 UI to 0.315 UI (34% improvement) at $10^{-12}$ BER level.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.6
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• pp.594-607
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• 2013

A new efficient analytical eye-diagram determination technique for coupled interconnect lines is presented. Two coupled lines are decoupled into isolated eigen modes; bit blocks for coupled lines, which are defined as a block of consecutive bits, are then represented with decoupled modes. The crosstalk effects within the bit blocks are taken into account. Thereby, the crucial input bit patterns for the worst case eye-diagram determination are modeled mathematically, including inter-symbol interference (ISI). The proposed technique shows excellent agreement with the SPICE-based simulation. Furthermore, it is very computation-time-efficient in the order of magnitude, compared with the SPICE simulation, which requires numerous pseudo-random bit sequence (PRBS) input signals.

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.367-372
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• 2009

In this paper we propose an electronic domain timing phase selection scheme for the optical communication systems suffering from inter-symbol-interference (ISI) distortion due to chromatic dispersion (CD) or polarization mode dispersion (PMD). In the presence of CD/PMD a proper timing phase selection is important for discrete time domain equalizers, since different timing phases produce different nonlinear ISI channels of different severity. The proposed timing phase recovery scheme based on dispersion minimization (DM) practically approximates the optimal minimum mean squared error (MMSE) timing phase without training signals which reduces overall throughput substantially, especially in time-varying channels such as PMD. The simulation results show that the proposed DM timing agrees with MMSE timing phase, under proper normalization of the received signals, for various dispersion and OSNR.

• ETRI Journal
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• v.37 no.5
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• pp.906-916
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• 2015

High-speed I/O channels require adaptive techniques to optimize the settings for filter tap weights at decision feedback equalization (DFE) read channels to compensate for channel inter-symbol interference (ISI) and crosstalk from multiple adjacent channels. Both ISI and crosstalk tend to vary with channel length, process, and temperature variations. Individually optimizing parameters such as those just mentioned leads to suboptimal solutions. We propose a joint optimization technique for crosstalk cancellation (XTC) at DFE to compensate for both ISI and XTC in high-speed I/O channels. The technique is used to compensate for between 15.7 dB and 19.7 dB of channel loss combined with a variety of crosstalk strengths from $60mV_{p-p}$ to $180mV_{p-p}$ adaptively, where the transmit non-return-to-zero signal amplitude is a constant $500mV_{p-p}$.

• Journal of the Optical Society of Korea
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• v.12 no.4
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• pp.249-254
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• 2008

In this paper we present an electronic domain solution for chromatic dispersion (CD) monitoring algorithm based on the estimated time domain channel in electronic domain using channel estimation methods. The proposed scheme utilizes kurtosis as a CD measurement, directly computed from the estimated inter-symbol-interference (ISI) channel due to the CD distortion. Hence, the proposed scheme exhibits robust performance under OSNR variation, in contrast to the existing electronic domain approach based on minimum mean squared error (MMSE) fractionally-spaced equalizer taps [1]. The simulation results verify the CD monitoring ability of the proposed scheme.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.15-20
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• 2015

Bit patterned media (BPM) is a high capacity storage system and has attracted a great deal of attention as next generation data storage. When BPM is made with high density, the space between the islands narrows, because BPM records one bit in an island. For this reason, BPM has inter-symbol interference in all directions, unlike in current storage systems where it is in only one direction. In this paper, we propose an equation for compensating two-dimensional ISI. We conduct experiments on track misregistration. When using the proposed inter-symbol interference preprocessing, the BER performance is improved, regardless of the amount of track misregistration.