• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.9
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• pp.514-518
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• 2014

The shingled magnetic recording method has interference between adjacent tracks. Furthermore, when read-head reads the data along the track, the head can be skewed by some physical effects. In this paper, in order to solve this problem, we propose a two-dimensional equalizer that uses two heads. If the head is skewed, it is possible to complement the performance by positioning the two heads at the center of the current track.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.8
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• pp.445-452
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• 2014

In this paper, we define ideal autocorrelation property for balanced quaternary sequence with even period. We also prove that our definition is ideal autocorrelation property for balanced quaternary sequence with even period. Furthermore, we propose a generation method of quaternary sequence with ideal autocorrelation property of period $2{\times}(2^n-1)$ using a binary sequence with ideal autocorrelation of period $2^n-1$ and Gray mapping. We also derive the autocorrelation value distribution of the newly proposed quaternary sequence.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.3
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• pp.121-126
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• 2014

Demand of the data storage becomes more and more growing. This requests the next generation of storage devices to have the dominated storage capability associated with superfast read/write rate. Holographic data storage (HDS) is investigated for a long time and is considered to be a candidate for the future storage system. However, it has two-dimensional intersymbol interference that conventional one-dimensional detection solutions have not yet handled strictly because of the complexity level of system as well as the cost. We propose a new scheme that combines iterative soft output Viterbi algorithm with noise filter for improving the bit error rate performance of HDS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.3
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• pp.158-160
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• 2014

Recently, owing to the development of active array antenna techniques, various sector beams can be applied to the LTE systems with vertical sectorization. In this paper, we evaluate the system performance and suggest an optimum beam combination and parameters by using a system level simulator

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.3
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• pp.140-148
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• 2014

In this paper, We proposed Gaussian function as a basis of hybrid method. Hybrid method is to extrapolate late time and high frequency data using early time and low frequency data. This method takes advantages of both MOT and MOM as well as having shorter running time and smaller error. For this method a better basis function is required. We compared the performance of the result with proposed function and conventional basis including Hermite and Laguerre polynomial.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.5
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• pp.326-328
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• 2014

In this paper we propose an efficient algorithm for LSA(Link State Advertisements) flooding. Link state routing protocols have been widely adopted in wired networks. When link state change occurs, a LSA is flooded into the whole network. The overhead of LSA flooding may be a big problem in wireless networks because their link states can be changed frequently. We propose an efficient flooding method that optimizes the flooding processes in wireless networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.2
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• pp.117-119
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• 2014

In this paper, we shows the simulation result of estimation algorithm for aircraft track which is core engine in MLAT system. The simulation result for 3D position estimation by Chan algorithm based on TDOA and Kalman filter shows that the performance satisfies the requirements of EUROCAE ED-117 over AWGN channel.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.2
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• pp.86-91
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• 2014

Holographic data storage (HDS) has a number of advantages, including a high transmission rate through the use of a charge coupled device array for reading two-dimensional (2D) pixel image data, and a high density capacity. HDS also has disadvantages, including 2d intersymbol interference by neighboring pixels and interpage interference by multiple pages stored in the same holographic volume. These problems can be eliminated by modulation codes. We propose a 7/9 error-correcting modulation code that exploits a Viterbi-trellis algorithm and has a code rate larger (about 0.778) than that of the conventional 6/8 balanced modulation code. We show improved performance of the bit error rate with the proposed scheme compared to that of the simple 7/9 code without the trellis scheme and the 6/8 balanced modulation code.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1C
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• pp.22-27
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• 2011

This paper proposes an efficient user selection algorithm that provides a maximum 셀 용량 based Multi-user MIMO system based on zero-forcing criterion. The proposed scheme forms a primary group of users whose channel power exceeds a predetermined threshold. Through computer simulations, we have found that the proposed method outperforms the conventional scheme yielding a sum rate that is 0.33 bps/Hz higher when the total numbers of users and transmit antennas in the cell are 100 and 4, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1C
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• pp.8-13
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• 2011

In this paper, we show new method to find error locations of 2 eight bit symbol errors for 2 error correcting Reed-Solomon decoder. New design is much faster and has much simpler logic circuit than the former design method. This optimization was possible by partitioning the 8 bit operations into 4 bit arithgmatic and logic operations. This Reed Solomon decoder can be used for data protection of almost all digital communication and consumer electronic devices.