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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Communications and Information Sciences
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The Korean Institute of Communications and Information Sciences
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Volume & Issues
Volume 33, Issue 12C - Dec 2008
Volume 33, Issue 12B - Dec 2008
Volume 33, Issue 12A - Dec 2008
Volume 33, Issue 11C - Nov 2008
Volume 33, Issue 11B - Nov 2008
Volume 33, Issue 11A - Nov 2008
Volume 33, Issue 10C - Oct 2008
Volume 33, Issue 10B - Oct 2008
Volume 33, Issue 10A - Oct 2008
Volume 33, Issue 9C - Sep 2008
Volume 33, Issue 9B - Sep 2008
Volume 33, Issue 9A - Sep 2008
Volume 33, Issue 8C - Aug 2008
Volume 33, Issue 8B - Aug 2008
Volume 33, Issue 8A - Aug 2008
Volume 33, Issue 7C - Jul 2008
Volume 33, Issue 7B - Jul 2008
Volume 33, Issue 7A - Jul 2008
Volume 33, Issue 6C - Jun 2008
Volume 33, Issue 6B - Jun 2008
Volume 33, Issue 6A - Jun 2008
Volume 33, Issue 5C - May 2008
Volume 33, Issue 5B - May 2008
Volume 33, Issue 5A - May 2008
Volume 33, Issue 4C - Apr 2008
Volume 33, Issue 4B - Apr 2008
Volume 33, Issue 4A - Apr 2008
Volume 33, Issue 3C - Mar 2008
Volume 33, Issue 3B - Mar 2008
Volume 33, Issue 3A - Mar 2008
Volume 33, Issue 2A - Feb 2008
Volume 33, Issue 2C - Feb 2008
Volume 33, Issue 2B - Feb 2008
Volume 33, Issue 1C - Jan 2008
Volume 33, Issue 1B - Jan 2008
Volume 33, Issue 1A - Jan 2008
Selecting the target year
A Synchronous Digital Duplexing Technique for Wireless Transmission in Indoor Environments
Park, Chang-Hwan ; Ko, Yo-Han ; Park, Kyung-Won ; Jeon, Won-Gi ; Paik, Jong-Ho ; Lee, Seok-Pil ; Cho, Yong-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 971~982
In this paper, we propose a new digital duplexing scheme, called SDD(Synchronous Digital Duplexing), which can increase data efficiency and flexibility of resource by transmitting uplink signal and downlink signal simultaneously. In order to transmit uplink data and downlink data simultaneously, the proposed SDD obtains mutual informations between AP(access point) and each SSs(subscriber station), SS and other SSs by mutual ranging procedure. These informations are used for selection of transmission time, decision of CS insertion, setting of CS length, and FFT duration resetting, etc. It is shown that the proposed SDD is appropriate for duplexing scheme in indoor environments over the conventional TDD(Time Division Duplexing) and FDD(Frequency Division Duplexing).
Error Probability Analysis for the Initial Acquisition Using Sum Differential Correlation Methods
Kim, Sang-Tae ; Kim, Jae-Won ; Chang, Dae-Ig ; Kim, Pan-Soo ; Sung, Won-Jin ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 983~990
In communication systems, initial acquisition is required for the reliable transmission performance, and the analysis of the acquisition performance over various communication environments including different signal-to-noise ratios plays an important role in communication system design. Usage of differential correlation methods in initial synchronization procedure is desired when frequency offsets exist, and additional performance improvement can be achieved through proper modifications of conventional correlation schemes. In this paper, we derive the error probability of the initial acquisition and express it in terms of the Marcum Q-function, via statistical modeling of the differential correlator output. The result is generalized to the error probabilities of the extended differential correlation methods using the complex- and magnitude-sum of the correlator outputs. The derived probabilities can be applied for the acquisition performance verification of various communication systems including the DVB-S2 standard.
Hybrid ARQ for LDPC-coded Systems
Ahn, Seok-Ki ; Myung, Se-Ho ; Yang, Kyeong-Cheol ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 991~996
In this paper, we propose an LDPC-coded hybrid ARQ system using incremental redundancy and retransmission of a part of the transmitted packets. We also present a simple criterion for choosing two methods to support a desired throughput efficiently. Furthermore, we show that the throughput performance can be improved when multi-edge type LDPC codes with the structure of Raptor codes are employed for a hybrid ARQ scheme.
The Study of Hierarchical Transmission Method for Additional Service of Advanced T-DMB
Kim, Min-Hyuk ; Park, Tae-Doo ; Kim, Nam-Soo ; Jung, Ji-Won ; Lee, Seong-Ro ; Choi, Myeong-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 997~1005
In this paper, we proposed advanced T-DMB system which is based on Eureka-147 using UEP coding methods and hiererchical modulation for providing additional services while maintaining BER performance. We simulated the proposed advanced T-DMB system using unequal l6QAM modulation scheme combined with various bit split methods and coding methods such as double binary turbo code of DVB-RCS standard and LDPC code of DVB-S2 standard. In the simulation results, double binary turbo code and LDPC code of proposed advanced T-DMB system have coding gain of 2dB and 3.5dB compared to conventional T-DMB system respectively.
Performance Analysis of CZZ Codes Using Degree-2 Polynomial Interleavers for Fading Channels
Yun, Jeong-Kook ; Yoo, Chul-Hae ; Shin, Dong-Joon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1006~1013
CZZ (Concatenated Zigzag) Code is a class of fast encodable LDPC codes. In the case that LDPC codes including CZZ codes have short length, short cycles seriously affect the code performance. In this paper, we construct CZZ codes using various degree-2 polynomial interleavers which eliminate cycles of length 4 and through simulation, compare the performance of these CZZ codes and turbo codes in many different fading channels. Especially, quasi-static fading channel, block fading channel, uncorrelated fading channel, and correlated fading channel are considered. Since CZZ codes show similar performance as turbo codes, they can be used in the next generation wireless communication systems.
Performance Analysis of Various Coding Schemes for Storage Systems
Kim, Hyung-June ; Kim, Sung-Rae ; Shin, Dong-Joon ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1014~1020
Storage devices such as memories are widely used in various electronic products. They require high-density memory and currently the data has been stored in multi-level format, that results in high error rate. In this paper, we apply error correction schemes that are widely used in communication system to the storage devices for satisfying low bit error rate and high code rate. In A WGN channel with average BER
, we study error correction schemes for 4-1evel cell to achieve target code rate 0.99 and target BER
, respectively. Since block codes may perform better than the concatenated codes for high code rate, and it is important to use less degraded inner code even when many bits are punctured. The performance of concatenated codes using general feedforward systematic convolutional codes are worse than the block code only scheme. The simulation results show that RSC codes must be used as inner codes to achieve good performance of punctured convolutional codes for high code rate.
Mutual Anonymous Authentication Using Smart Cards in Multi-server Environments
Yoo, Hye-Joung ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1021~1028
In a network environment, when a user requests a server's service, a remote user authentication system using smart cards is a very practical solution to validate the eligibility of a user and provide secure communication. In these authentication schemes, due to fast progress of networks and information technology, most of provided services are in multi-server environments. However, there are no studies in multi-server authentication schemes using smart cards providing mutual anonymity so far. In this paper, we propose a novel user authentication scheme using smart cards providing mutual authentication and mutual anonymity for multi-server environments. Our proposed scheme achieves the low-computation requirement for smart cards and a user can use permitted various services in eligible servers by only one registration. Also, this scheme guarantees perfect mutual anonymity of participants.
Compensation Method for Occluded-region of Arbitrary-view Image Synthesized from Multi-view Video
Park, Se-Hwan ; Song, Hyuk ; Jang, Eun-Young ; Hur, Nam-Ho ; Kim, Jin-Woong ; Kim, Jin-Soo ; Lee, Sang-Hun ; Yoo, Ji-Sang ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1029~1038
In this paper, we propose a method for an arbitrary-view image generation in multi-view video and methods for pre- and post-processing to compensate unattended regions in the generated image. To generate an arbitrary-view image, camera geometry is used. Three dimensional coordinates of image pixels can be obtained by using depth information of multi-view video and parameter information of multi-view cameras, and by replacing three dimensional coordinates on a two dimensional image plane of other view, arbitrary-view image can be reconstructed. However, the generated arbitrary-view image contains many unattended regions. In this paper, we also proposed a method for compensating these regions considering temporal redundancy and spatial direction of an image and an error of acquired multi-view image and depth information. Test results show that we could obtain a reliably synthesized view-image with objective measurement of PSNR more than 30dB and subjective estimation of DSCQS(double stimulus continuous quality scale method) more than 3.5 point.
Efficient Intra Prediction Mode Decision Method using Integer Transform Coefficients for the Transcoding of MPEG-2 to H.264 Standard
Kim, Yong-Jae ; Lee, Chang-Woo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1039~1045
The H.264/AVC video coding standard shows extremely higher coding efficiency, but it causes high computational complexity. Especially, the intra mode decision using the rate-distortion method requires many computations. Thus, the efficient intra mode decision methods have been proposed by decreasing the encoding complexity. In this paper, we propose an efficient intra mode decision algorithm using
integer transform coefficients in the conversion of MPEG-2 to H.264 standard. It is shown that the proposed algorithm reduces encoding time and complexity compared to the conventional algorithm, while showing similar PSNR performance.
Intra MB Prediction Mode Decision Method for Fast MPEG-2 to H.264/AVC Transcoding
Liu, Xingang ; Yoo, Kook-Yeol ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1046~1054
Since the high quality digital TV systems are broadly deployed in the market, the digital video contents will be edited and distributed in MPEG-2 MP@HL fonnat. Due to its impressive coding efficiency, the H.264/AVC codec has rapidly replaced the MPEG-4 SP codec for mobile digital video terminal with low quality. For the bro ad distribution of digitial video contents produced in MPEG-2 format, the MPEG-2 to H.264/AVC transcoding is highly necessary nowadays. In this paper, we propose a fast intra MB prediction mode decision method to reduce the computational complexity in the transcoding, which is the main bottleneck in the transcoders. The proposed method is based on the several relationships such as DCT coefficients and edge orientation, correlation between prediction directions in the
modes, correlation between edge-orientations of luminance an d chrominance components. The simulation results show that the proposed method can reduce the computational complexity upto 70% and 40%, compared with the cascaded transcoder and the well-known fast intraframe transc oder, respectively.
Adaptive Intra Fast Algorithm of H.264 for Video Surveillance
Jang, Ki-Young ; Kim, Eung-Tae ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1055~1061
H.264 is the prominent video coding standard in various applications such as real-time streaming and digital multimedia broadcasting, since it provides enhanced compression performance, error resilience tools, and network adaptation. Compression efficiency of H.264 has been improved, however, it requires more computing and memory access than traditional methods. In this paper we proposed adaptive intra fast algorithm for real-time video surveillance system reducing the encoding complexity of H264/A VC. For this aim, temporal interrelationship between macroblock in the previous and the current frame is used to decide the encoding mode of macroblock fast. As a result, though video quality was deteriorated a little, less than 0.04dB, and bit rate was somewhat increased in suggested method, however, proposed method improved encoding time significantly and, in particular, encoding time of an image with little changes of neighboring background such as surveillance video was more shortened than traditional methods.
New Design for Linear Complex Precoding over ABBA Quasi-Orthogonal Space-Time Block Codes
Ran, Rong ; Yang, Jang-Hoon ; An, Chan-Ho ; Kim, Dong-Ku ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1062~1067
ABBA codes, a class of quasi-orthognal space-time block codes (QoSTBC) proposed by Tirkkonen and others, allow full rate and a fast maximum likelihood (ML) decoding, but do not have full diversity. In this paper, a linear complex precoder is proposed for ABBA codes to achieve full rate and full diversity. Moreover, the same diversity produce as that of orthogonal space-time block code with linear complex precoder (OSTBC-LCP) is achieved. Meanwhile, the size of the linear complex precoder can be reduced by half without affecting performance, which means the same complexity of decoding as that of the conventional ABBA code is guaranteed.
Generating the Array of Elemental Image efficiently by using Look-Up Table in Integral Imaging System
Kwon, Young-Man ; Kim, Seung-Chul ; Kim, Eun-Soo ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1068~1074
In this paper, we propose the algorithm for generating the array of elemental image by using look-up table (L UT) in a computer generated integral imaging system. It makes the LUT independently for the projection point of x and y. The algorithm using LUT to the existing ones needs less computing time to generate the array of elemental image. By comparing the computing time of proposed algorithm with that of the existing algorithms e xperimently, we proved the efficiency of proposed algorithm.
An Optical CDMA Code Acquisition Algorithm Using Multiple Thresholds
Chong, Da-Hae ; Lee, Young-Yoon ; Ahn, Sang-Ho ; Lee, Seong-Ro ; Yoon, Seok-Ho ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1075~1081
In this paper, we propose a code acquisition algorithm using optical orthogonal code (OOC) for optical code division multiple access (CDMA) systems. Generally, a good code acquisition algorithm offers short mean acquisition time (MAT). The conventional multiple-shift (MS) algorithm consists of two stages and has shorter MAT than that of well-known serial-search (SS) algorithm. This paper proposes a novel code acquisition algorithm called enhanced multiple-shift (EMS) algorithm. By using multiple thresholds, the proposed EMS algorithm provides shorter MAT compared with that of the MS algorithm. The simulation results show that the EMS algorithm presents shorter MAT compared with the MS algorithm in both single-user and multi-user environments.
Feedback Semi-Definite Relaxation for near-Maximum Likelihood Detection in MIMO Systems
Park, Su-Bin ; Lee, Dong-Jin ; Byun, Youn-Shik ;
The Journal of Korean Institute of Communications and Information Sciences, volume 33, issue 12C, 2008, Pages 1082~1087
Maximum Likelihood (ML) detection is well known to exhibit better bit-error-rate (BER) than many other detectors for multiple-input multiple-output (MIMO) channel. However, ML detection has been shown a difficult problem due to its NP-hard problem. It means that there is no known algorithm which can find the optimal solution in polynomial-time. In this paper, Semi-Definite relaxation (SDR) is iteratively applied to ML detection problem. The probability distribution can be obtained by survival eigenvector out of the dominant eigenvalue term of the optimal solution. The probability distribution which is yielded by SDR is recurred to the received signal. Our approach can reach to nearly ML performance.