• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.296-302
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• 2013

The binary offset carrier (BOC) modulation has attracted much attention as a new physical layer implementation for satellite communication and global navigation satellite systems. In this paper, we propose a new correlation function for sine-phased BOC signals. Specifically, we separate a sub-carrier pulse into several rectangular pulses, and then, generate a number of partial correlation functions. Finally we combine the partial correlation functions to yield an unambiguous correlation function with no side-peak. From numerical results, it is demonstrated that the proposed correlation function provides a significant tracking performance improvement over the conventional correlation functions.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.288-295
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• 2013

In this paper, we compare the existing channel estimation technique for 4S (Ship to Ship, Ship to Shore) maritime communications under AWGN channel model, Rician fading channel model, and Rayleigh fading channel model respectively. In general, the received signal is corrupted by multipath and ISI (Inter Symbol Interference). The estimation of a time-varying multipath fading channel is a difficult task for the receiver. Its performance can be improved if an appropriate channel estimation filter is used. The simulation is performed in MATLAB. In this simulation, we use the popular estimation algorithms, LMS (Least Mean Square) and RLS (Recursive Least-Squares) are compared with respect to AWGN, Rician and Rayleigh channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.303-310
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• 2013

Underwater acoustic communication has multipath error because of reflection by sea-level and sea-bottom. The multipath of underwater channel causes signal distortion and error floor. In order to improve the performance, it is necessary to employ an iterative coding scheme. Among the iterative coding scheme, turbo codes and LDPC codes are dominant channel coding schemes in recent. This paper concluded that turbo coding scheme is optimal for underwater communications system in aspect to performance, coded word length, and equalizer combining. Also, we confirmed the performance in the environment of oceanic experimentation using turbo equalizer based on distance 5Km, data rate 1Kbps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.327-333
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• 2013

In this paper, we propose a QoS information collection method at the information server in maritime networks with multi-network interfaces, and a route selection scheme based of the measured predictive QoS information comparing with parameters requested from a mobile node in a ship entering into a harbor from near-shore area. By changing network conditions and applying various application bandwidths, we check the operation of our proposed scheme and measure its performance of the original and proposed schemes in the viewpoints of the received packet traffic and end-to-end delays.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.3
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• pp.318-326
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• 2013

In this paper, a novel WUSB (Wireless USB) over WBAN (Wireless Body Area Networks) MAC protocol is proposed to improve efficiency of sensing the personal information. Furthermore, a localization technique based on that protocol is also proposed for indoor localization in a ship. For this purpose, the proposed localization algorithm minimizes power consumption and estimates location with accuracy. It is executed independently at each sensor node on the basis of WUSB over WBAN protocol. And it minimizes power consumption by estimating locations of sensor nodes without GPS (Global Positioning Systems).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.2
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• pp.146-153
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• 2013

The IR-UWB radar system radiates a pulse whose width is several hundred pico sec at Tx antenna and check the time to receive the pulse that reflected from target to measure the TOA. In this paper, we present a new algorithm which supplement the conventional ranging algorithm for more accurate estimation. We get received signal data using IR-UWB Radar module which equipped a NVA6000 UWB Transceiver and analysis the data of multi-path. Consequently, we found the property of UWB multi-path signal, which best fit a Gamma distribution. so we present a algorithm using Gamma-distribution and compared a performance with conventional ranging algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.5
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• pp.409-415
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• 2013

In this paper, we propose a correlation function using newly designed local signals for cosine-phased binary offset carrier (BOC) signal tracking. First, we divide a sub-carrier pulse over one pseudo random noise code period into multiple rectangular pulses, and subsequently, design novel local signals. Then, we obtain a correlation function with no side-peak based on a combination of correlations between the newly generated local signals and received cosine-phased BOC signal. From numerical results, it is confirmed that the proposed correlation function provides a tracking performance improvement over the conventional correlation functions in terms of the tracking error standard deviation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.5
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• pp.436-442
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• 2013

The diversity-multiplexing tradeoff (DMT) function of a special half-duplex (HD) dynamic decode and forward (DDF) relay protocol with more than two antennas at the source node, two antennas at the relay node, and two antennas at the destination node is derived. This protocol is compared to a HD NAF protocol with the same number of source antennas and a HD DDF relay protocol with two antennas at the source node, more than two antennas at the relay node, and two antennas at the destination node.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.10
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• pp.911-919
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• 2013

Evaluation of the effect of radial distortion for a holographic stereogram demands conducting an experiment which comprises rendering of a 3D obejc, acquisition of perspective images, rearrangement of the acquired images for hogel images and quality assessment of the observing image reconstructed from the holographic stereogram. We propose numerical implementation of this evaluation by a specially developed algorithm for modeling of all required steps. The modeling is done by using a numerical model of an optical engine for generation of radially distorted hogel images at various degrees of distortion. The distorted images are used to form the holographic stereogram and to make the numerically reconstructed images from the holographic stereogram which are observed by an observer at desired location. The reconstructed images are compared by using PSNR.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.10
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• pp.852-857
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• 2013

In this paper we propose a design algorithm for nonbinary LDPC (low-density parity-check) codes with low error-floors. The proposed algorithm determines the nonbinary values of the nonzero entries in the parity-check matrix in order to maximize the binary minimum distance of the designed nonbinary LDPC codes. We verify the performance of the designed nonbinary LDPC codes in the error-floor region by Monte Carlo simulation and importance sampling over BPSK (binary phase-shift keying) modulation.