• ETRI Journal
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• v.33 no.6
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• pp.849-856
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• 2011

This research introduces three new fractal array configurations that have superior performance over the well-known Sierpinski fractal array. These arrays are based on the fractal shapes Dragon, Twig, and a new shape which will be called Flap fractal. Their superiority comes from the low side lobe level and/or the wide angle between the main lobe and the side lobes, which improves the signal-to-intersymbol interference and signal-to-noise ratio. Their performance is compared to the known array configurations: uniform, random, and Sierpinski fractal arrays.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.61-64
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• 2002

In this paper, various equalizers are considered to improve the performance of Home Phoneline Networking Alliance (HomePNA) 2.0 system under dispersive channel with intersymbol interference. We evaluate and compare the performances of Recursive Least Squares (RLS) and Least Mean Squares (LMS) adaptation algorithms. Computer simulations show that the equalizers utilizing tile RLS algorithm outperforms the LMS algorithm, especially for the system of high symbol rate and complex constellation.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.1 no.2
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• pp.199-207
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• 1997

The Maximum Likelihood Sequence Estimation scheme is modified to improve the error performance of the correlative coding in the Tamed FM. To remove intersymbol interference, the Decision Feedback Equalization scheme with the delayed LMS algorithm and the Viterbi algorithm(10-symbol delay) in the delayed adaptive equalization are proposed for the performance of decision-directed adaptive equalization under the High Frequency channels, and the condition of convergence is analyzed.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.238-241
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• 2003

This paper presents a nonlinear least squares decision feedback equalizer Bilinear systems are attractive because of the ability to approximate a large class of nonlinear systems efficiently. The nonlinearity of channel is modeled using a bilinear system. The algorithms are derived by using the QR decomposition for minimization covariance matrix of prediction error by applying Givens rotation to the bilinear model. Result of computer simulation experiments that compare the performance of the bilinear DFE to two other DFE's in eliminating the intersymbol interference caused by a nonlinear channel are presented In the paper.

• Transactions of the Society of Information Storage Systems
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• v.6 no.2
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• pp.47-51
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• 2010

We investigate misalignment characteristics of 5/8 modulation code for holographic data storage. The 5/8 modulation code does not have any isolated patterns that is the most unwanted problem for holographic data storage. As the results, the 5/8 modulation code showed a strong side of misalignments, and the code has the best performance among uncoded, 5/9, and 6/8 modulation codes when there are large misalignments.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.1-4
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• 2000

In this paper, A useful nonlinear function for the RBF(Radial Basis Function) equalization is proposed. This proposed function need not calculate an exponential function that is generally used for conventional RBF equalizer and uses the only four rules of arithmetic. Therefore the computational requirement for the RBF equalizer with the proposed function is decreased. As a computer simulation result, the equalizer with the proposed function effectively reduce nonlinear intersymbol interference, caused by nonlinear communication channel.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.4
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• pp.262-266
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• 2013

In OFDM system, cyclic prefix (CP) is used to eliminate the inersymbol interference that is caused by the channel dispersion. However, a long CP reduces the data transmission rate. An alternative to a logn CP is the a time domain channel shortening filter at the receiver that shortens the effective channel, thus a short CP is used in spite of a long channel impulse response. In the paper, we compare a various channel shortening techniques; minimum shortened signal to noise ratio (MSSNR), minimum interblock interference (min-IBI), and minimum ISI (min-ISI).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.11C
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• pp.851-859
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• 2008

This paper investigates the effect a guard period (GP) in the form of a cyclic prefix for asynchronous multicarrier-code division multiple access (MC-CDMA) systems. At first, we analyze the performance of asynchronous MC-CDMA systems with a GP, which results in closed-form bit error rate (BER) performance. Furthermore, it confirms that the frequency diversity of MC-CDMA systems is identical to the path diversity. The analytical approach proposed here is extended to the case without a GP. The derived analytical results show that a GP is required for MC-CDMA systems in order to mitigate not only the effect of intersymbol interference (ISI) and intercarrier interference (ICI) but also the desired signal power degradation. In addition, the accuracy of the proposed analysis is verified by simulations.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12C
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• pp.971-976
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• 2010

We introduce an error correcting 4/6 modulation codes for holographic data storage, and simulate under adding mis-alignment noise. The holographic data storage has two-dimensional intersymbol interference. To increase the channel performance, it is necessary to use modulation code. Furthermore, if the modulation code has trellis structure, error correcting capability is added. The error correcting 4/6 modulation code shows better performance than conventional modulation codes with and without mis-alignment noise.